## Monday, December 10, 2012

### Calculating Heading Or Bearing Angle Of GPS Coordinates

Heading is the direction you are walking or driving a vehicle or flying, it is using units of degrees with the north as a point of 0 or 360 degrees. East is 90 degrees, south is 180 degrees, and west as 270 degrees. North may use the magnetic north (compass), but can also use an absolute north (North Pole).

In this attached excel sheet, I use the absolute north as a point of north or 0 degree.

Suppose you are walking from point A to point C, or from starting point to a camp as the above picture, through point B or a bridge at north. Start at point A, you move to the north to point B, or the so-called heading 0 degree, as far as 10 km. Arriving at point B, you turn to the right, or the so-called 90-degrees heading and walk towards point C with 10 km distance. Bearing is the angle of the starting point towards the end of the journey or the destination point, or position of an object from the observer. So a bearing, can be composed of several headings. In the example above, bearing from point A to point C is 45 degrees. Bearing is also called azimuth.

GPS coordinate system used on the Excel sheet is a decimal number, because it is more easily calculated. On ‘conversion’ sheet, there are formulas to change decimal number to sexagesimal (degrees minutes seconds).

Please note the sequence of latitude and longitude coordinate, not to reverse. Google Maps uses a system of latitude and longitude (y and x), instead of as usual in mathematics longitude and latitude (x and y).

Heading when start is not always the same as when finish, especially for long distance. If we are near the equator, heading at the beginning and at the end of travel can be almost the same. It is because of our position on the north and south poles are always about the same. For example a flight conducted along the equator toward the east (heading 90 degrees). As long as the aircraft follows the equator and towards the east, in any position, the north pole is always on the left, and the south pole is always on the right of that aircraft.

Likewise, if we fly along the line of latitude. Eg from the south pole to the north pole. During the trip, either at the start or near the destination, north pole position is always in front and the south pole is always in the back. So heading at the start and at the end of flight is almost the same 0 degree.

But if the journey is done over the pole, for example: the north pole, at the beginning of the trip heading 0 or 360 degrees. When passing over the north pole (90,0), the heading will change to 180 degrees.

For example: flights from Pulkovo International Airport, Saint Petersburg, Russia (59.800278, 30.262500) to the Ted Stevens Anchorage International Airport, Alaska, United States of America (61.17417, -149.99833). At Saint Petersburg, Russia after take off; initial heading 0.147 or to the north, when approaching Anchorage just before landing, heading is changed to 179.844 or heading to the south. Even though the flight is following straight line. And the shortest distance between Saint Petersbug to Anchorage is over the north pole.

So to explain the flight path, mid point needs to be calculated, ie the point in the middle of a trip. Saint Petersburg flight towards Anchorage has mid point at (89.309101, 36.265637). Heading at the mid point is 6,130 degrees.

Another example: a flight from Bordeaux Airport, Merignac, France (44.830309, -0.701237) to Toronto Pearson International Airport, Mississauga, Ontario, Canada (43.67768, -79.624958). After takeoff in Bordeaux, flight will be heading to 298.900 degrees. Half way will be at mid point (51.605128, -40.625340) and heading will become 268.540 degrees. Before landing in Toronto, the final heading is 239.258 degrees. So after take off flight heads to approximately north-west, at the mid point heads to the west, while approaching Toronto flight heads to approximately the southwest.

Both cities Bordeaux and Toronto are at nearly the same latitude line, which is about 44 degrees north latitude. But because the shape of the globe, the shortest distance between the two cities does not follow that latitude line. The shortest distance between Bordeaux and Toronto is over the mid point located at 51.6 degrees north latitude, about 8 degrees more to the north of the latitude of Bordeaux and Toronto. If flying from Bordeaux to Toronto follows the line of 44 degrees north latitude, it will always be a constant heading of about 270 degrees. The north pole will always be on the right, and the south pole is always on the left.

Earth radius used is 6,378.14 km and it is radius of the earth at the equator. Earth radius number can be adjusted for better accuracy because the earth is not perfectly round. The average value of earth radius is 6371 km. While the Earth's polar radius is 6,356.7523 km.

If using Google Maps, then the calculation result can be copied and paste in the Search box on Google Maps, then press the Search button. Google Maps will show the intended point on the map.

## Monday, November 19, 2012

### Menghitung Sudut Heading Atau Bearing Dari Koordinat GPS

Heading adalah arah anda atau kendaraan berjalan, menggunakan satuan derajat dengan utara sebagai titik 0 atau 360 derajat. Timur adalah 90 derajat, selatan 180 derajat, dan barat sebagai 270 derajat. Titik utara dapat sebagai utara magnetik (kompas), tapi bisa juga menggunakan utara absolut (kutub utara).

Dalam lembar excel terlampir, saya menggunakan titik utara absolut sebagai titik 0 derajat

Lihat gambar dibawah: misalkan anda berjalan dari titik A menuju titik C (camp), melalui titik B (jembatan di utara). Pada saat start di titik A, anda bergerak ke utara, atau disebut heading 0 derajat, menuju titik B sejauh 10 km. Sesampainya di titik B, anda berbelok ke kanan, atau disebut heading 90 derajat dan berjalan menuju titik C sejauh 10 km.

Bearing adalah sudut dari titik awal menuju titik tujuan atau akhir perjalan, atau posisi suatu objek dari pengamat. Jadi dalam suatu bearing, dapat terdiri dari beberapa heading. Pada contoh diatas, bearing dari titik A menuju titik C adalah 45 derajat. Bearing disebut juga sebagai azimuth.

Sistem koordinat GPS yang digunakan pada lembar Excel tersebut adalah angka desimal, karena lebih mudah dikalkulasi. Pada sheet conversion terdapat rumus yang dapat merubah angka desimal menjadi sexagesimal (derajat menit detik). Program Excel menggunakan sistem desimal Amerika dimana desimal ditandai dengan titik bukan koma. Sedangkan ribuan ditandai dengan koma, bukan titik.

Mohon diperhatikan bahwa koordinat bujur (longitude) dan lintang (latitude) jangan sampai terbalik. Google Maps menggunakan sistem lintang dan bujur (y dan x), bukan sebagaimana biasanya pada matematika bujur dan lintang (x dan y).

Heading di saat start tidak selalu sama dengan di saat finish, terutama untuk jarak jauh. Jika kita berada disekitar khatulistiwa atau equator, heading awal dan akhir bisa hampir sama. Hal ini karena posisi kita terhadap kutub utara maupun Selatan selalu hampir sama. Misal suatu penerbangan dilakukan sepanjang garis khatulistiwa ke arah timur (heading 90 derajat). Maka selama pesawat tersebut berada digaris khatulistiwa dan mengarah ke timur, dimanapun posisinya, kutub utara selalu disebelah kiri, dan kutub Selatan selalu disebelah kanan pesawat.

Demikian juga jika kita terbang dari sepanjang garis lintang. Misal dari kutub selatan menuju kutub utara. Selama perjalanan, baik saat start maupun mendekati tujuan, posisi kutub utara selalu di depan dan kutub selatan selalu di belakang. Jadi heading pada saat start dan pada saat mencapai tujuan, selalu hampir sama yaitu heading 0 derajat.

Tapi jika perjalanan dilakukan melalui kutub, misalnya kutub utara, saat awal perjalanan heading 0 atau 360 derajat. Ketika melewati titik kutub utara (90,0), maka heading akan berubah menjadi 180 derajat.

Misalnya: penerbangan dari Pulkovo International Airport, Saint Petersburg, Russia (59.800278, 30.262500) menuju Ted Stevens Anchorage International Airport, Alaska, United States of America (61.17417, -149.99833). Pada saat awal di Saint Petersburg, Rusia; sesudah lepas landas heading ke arah 0.147 atau ke utara, pada saat akan mendarat maka heading berubah menjadi 179.844 atau ke selatan, walau sebenarnya penerbangan yang dilakukan bergerak di jalur lurus, tidak berbelok. Dan jarak terdekat antara Saint Petersbug dengan Anchorage adalah melalui sekitar kutub utara.

Maka untuk memperjelas jalur yang dilalui, dikalkulasi juga mid point, yaitu titik di pertengahan perjalanan. Titik tengah penerbangan Saint Petersburg menuju Anchorage adalah di titik (89.309101, 36.265637). Heading pada mid point adalah 6.130 derajat.

Contoh lainnya: perjalanan udara dari Bordeaux Airport, Merignac, Perancis (44.830309,-0.701237) menuju Toronto Pearson International Airport, Mississauga, Ontario, Canada (43.67768,-79.624958 ). Sesudah tinggal landas di Bordeaux akan mengarah atau heading ke 298.900 derajat. Saat pertengahan perjalanan akan mencapai mid point (51.605128, -40.625340) dan heading berubah menjadi 268.540 derajat. Saat mendekati Toronto, maka final heading adalah 239.258 derajat. Jadi setelah lepas landas penerbangan mengarah ke sekitar barat laut, di mid point mengarah ke barat, saat sebelum mendarat di Toronto pesawat mengarah ke sekitar barat daya.

Kedua kota Bordeaux dan Toronto berada pada garis lintang yang hampir sama, yaitu sekitar lintang utara 44 derajat. Tapi karena bentuk bola bumi, jarak terdekat antara kedua kota tidak mengikuti garis lintang tersebut. Jarak terdekat diantara Bordeaux dan Toronto adalah melalui titik pertengahan atau mid point yang berada pada lintang utara 51.6 derajat, sekitar 8 derajat lebih ke utara dari garis lintang pada kedua kota Bordeaux dan Toronto. Jika penerbangan dari Bordeaux ke Toronto mengikuti garis lintang utara 44 derajat, maka heading akan selalu konstan sekitar 270 derajat, kutub utara akan selalu di sebelah kanan, dan kutub selatan selalu di sebelah kiri.

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## Saturday, November 17, 2012

### Adjustable Twinkle Light Switch For 200 Watts Lamp

Twinkle light switch which is also often called the flasher, usually use fluorescent lamp starter. But fluorescent starter has irregular twinkle and often do not twinkle at all.

Flasher discussed here can be used with 220 VAC and lamp power ranging from 5 watts to 200 watts. As we can see in the above video, the flasher is being tested with 2 (two) 100-watt lamps, so the total power is 200 watts or equal to 40 of 5 watt bulbs commonly used as decorative lighting.

This flasher is a very efficient switch and consume power less than 0.2 watts for itself to operate.

Wiring connection as below schematic:

The wiring connection is very simple. The blue wire from the flasher is connected to the twinkle bulb (B), another wire from the bulb is connected to the power grid. Red wire from the flasher is connected to a fuse (F) with a maximum size of 1 ampere, and the fuse is connected to the power grid. This way the flasher is protected from large currents directly from the grid, and ensure the best performance.

Twinkling light can be adjusted. This flasher is suitable for twinkling lights for celebration, party, Christmas, New Year, decorative lighting for store, restaurant, entertainment, and others.

For comparison, the following video using fluorescent light starter as a flasher.

Photo below shows a twinkle light switch that is packaged in a box, for the circuit schematic can be read in the article: Adjustable Twinkle Light 200 Watts 220 VAC Schematic.

## Thursday, October 25, 2012

### Saklar Lampu Kedip 200 Watt Yang Dapat Disetel

Saklar lampu kedip yang juga sering disebut sebagai flasher biasanya menggunakan starter lampu neon. Kelemahan starter lampu neon adalah kedipannya tidak beraturan bahkan sering tidak berkedip sama sekali.

Flasher yang dibahas disini dapat digunakan untuk lampu 220 VAC berdaya lampu mulai dari 5 watt sampai dengan 200 watt. Pada video di atas tampak flasher sedang ditest dengan 2 (dua) buah lampu 100 watt, sehingga berdaya total 200 watt atau sama dengan 40 buah lampu 5 watt yang biasa dipakai sebagai lampu hias.

Flasher ini adalah saklar yang sangat effisien, hanya mengkonsumsi daya kurang dari 0,2 watt untuk dirinya sendiri untuk beroperasi.

Penyambungan kabel sebagaimana skema dibawah:

Penyambungan kabel sangat sederhana. Kabel biru dari flasher dikoneksikan dengan lampu (B) yang akan berkedip, kabel lain dari lampu dihubungkan dengan jaringan listrik. Kabel merah dari flasher dihubungkan dengan sekring (F) dengan ukuran maximal 1 ampere, dan sekring terhubung dengan jaringan. Dengan demikian flasher terjaga dari arus yang besar langsung dari jaringan, dan menjamin performa terbaiknya.

Kedipan dapat disetel. Flasher ini cocok digunakan untuk lampu kedip pada perayaan 17-Agustus, Natal, tahun baru, lampu hias toko, restoran, salon, tempat hiburan, dan lain-lain.

Sebagai perbandingan, video berikut menggunakan starter lampu neon sebagai flasher.

Foto dibawah memperlihatkan saklar lampu kedip yang sudah dikemas dalam box, untuk skema rangkaiannya dapat dibaca di artikel: Skema Lampu Kedip 200 Watt 220 VAC Yang Dapat Disetel.

## Sunday, October 14, 2012

### Changing Voltage 220 VAC to 24 VDC Without Transformer

The following schematic is an electronic circuit to convert voltage of 220 VAC to 24 VDC without a transformer. The price can be reduced as we do not need to purchase and install the transformer, and the circuit is also smaller size and lighter weight. Power efficiency can also be higher, because the transformer has power loss with efficiency of about 89% at full load, and about 65% at half load.

For circuit with transformer please read "Power Supply, Battery Charger, With Transformer".

The circuit above is connected directly to the high voltage 220 VAC, so we should install a fuse. I use a 0.5 ampere fuse though slightly oversize. As far as I know the smallest type of glass fuse available on the market is 0.25 amperes, but sometimes it is hard to find. This fuse protects the high voltage section only, the circuit on the left of transistor. While the low voltage circuit is not protected as it produces a very small output current about 20 milliamps, so if that output is shorted it will not brake the fuse.

In principle, this circuit is the voltage stabilization circuit by a zener diode.  The output voltage will not be affected by input voltage fluctuation, as long as the input voltage is greater then zener voltage.

Read also laptop charger can be used to recharge car battery.

Input voltage will affect maximum output current. The higher the input voltage, the greater maximum output current, so if the input voltage decreases the maximum output current decreases. If the load requires current flow under maximum level, then when the input voltage drops will not affect the load voltage, or the output voltage. So, this circuit can work at a voltage of 220 VAC and 110 VAC. For 110 VAC input voltage, if you want to produce the same maximum current as with the input voltage 220 VAC, change the resistor values ​​of RB and RC to be half the value of which are described below.

I use a diode bridge (D), because it was available already in my stock. Actually diodes must be adjusted to the capacity of current and voltage. 4 pieces of 1N4007 diode can do, which is able to transmit current up to 1 ampere and a maximum voltage of 1000 volts.

Condenser 1 (C1) is 1 microfarads capacity and should have a maximum voltage above 220 volts. I use a 350 volts maximum voltage.

Base resistor (RB) will determine current fed to the base of the transistor. I use a 390k resistor at the base, so that the emitter current of transistor will be about 20 milliamps. If that base resistor is reduced, then the emitter current will be greater. If you need bigger emitter current, make sure the transistor is not too hot. If you do not have a thermometer to measure transistor heat, there is a simple way to determine whether the transistor is not too hot, by touching transistor with your finger. Make sure the transistor is not too hot and still can be touched by finger after loaded in about a minute. Before touching the transistor with your finger, make sure the high voltage is disconnected.

Collector resistor (RC) will protect the transistor and the load if the current rise above the limit. I use 10 kilo ohm resistor to limit output or emitter current of about 20 milliamps. This resistor can be reduced to increase the current.

Zener diode (DZ) determines the output voltage of the emitter. I use a 24 volt zener with power 1/2 watt. Note that the output voltage of transistor emitor will be reduced 0.6 volts. So if you use 24 volt zener, then the output voltage will be 23.4 volts. You can change this zener diode according to your output voltage requirement. The voltage produced is quite stable.

Transistor (T) is TIP50. According to the specification can transmit up to 2 watts continuous power. This transistor is able to work with the collector-emitter voltage of 400 volts (Vceo). DC current gain (hFE) transistor in the circuit is about 39. Needs to ensure manufacturer specification of TIP50 transistor that you use. This transistor needs a heatsink. Although for a current of 20 milliamps and voltage output of 24 volts will not make this transistor hot. But since we are working with high voltage, fatal incident will be happened if something goes wrong. Transistor is susceptible to overheating and can burst or explode in less than 1 (one) second, if there is a wrong connection when assembly and causing overload or short circuit. Transistor heatsink is connected to the collector so it has high voltage when circuit is connected to the power grid.

If you need bigger current above 100 milliamps, you can use bigger high voltage transistor 2SC3527 and connected as Darlington pair. Darlington pair is two transistors with paraleled collectors, the base of the larger transistor is supplied by smaller transistor’s emitor, the output is taken from the bigger transistor’s emitter. Darlington pair is activated by supplying a small current to the smaller transistor base. In other words, the Darlington pair is smaller transistor supplying bigger transistor base to generate large current. Output voltage will be reduced by 1.2 volts from zener voltage when using a Darlington pair. Resistor RC value can be lowered.

Output condenser (C2) filters output voltage fluctuations . I use a 50 volt 4.7 microfarads condensor.

Resistor at the output (RI) prevents high voltage spike induced by load which can damage the transistor, when used to supply inductive load. RI value is 10 kilos. This resistor can be omitted if not using an inductive load. This resistor can be replaced with a zener diode. If using a zener, it can protect the equipment if any increase in output voltage of transistor, and only needs a very small leakage current. The minimum voltage of output zener is equal to the zener on transistor’s base, in this case 24 volts. Maximum output zener voltage is 1 volt above the base zener, in this example is 25 volts. Zener installation is unlike normal diode, zener is installed upside down, because it just works or connects when zener voltage is exceeded. Zener cathode (negative) is connected to positive output, and zener anode (positive) is connected to the negative output. I use a resistor because it is more flexible, does not need to be replaced even though the zener on base of the transistor is changed.

WARNING: Do not touch the circuit when connected to high voltage, make sure you are using insulated electrical equipment, make sure the fuse is installed before the circuit is connected to the high voltage.

As the circuit is very simple, it can be assembled on matrix board.

## Thursday, September 13, 2012

### Mengubah Tegangan 220 VAC ke 24 VDC Tanpa Trafo

Skema berikut adalah rangkaian elektronik untuk mengubah tegangan 220 VAC ke 24 VDC tanpa transformator. Sehingga harga dapat ditekan murah karena tidak perlu membeli dan memasang trafo, ukuran lebih kecil dan berat lebih ringan. Juga effisiensi daya bisa lebih tinggi, karena trafo mempunyai borosan daya atau effisiensi sekitar 89% pada beban penuh, dan sekitar 65% pada beban setengah daya.

Untuk rangkaian dengan transformator dapat dibaca di "Power Suplai, Battery Charger, Dengan Trafo".

Rangkaian diatas terhubung langsung dengan tegangan tinggi 220 VAC, sehingga harus memasang sekring. Saya menggunakan sekring 0,5 ampere walau agak kebesaran. Setahu saya sekring terkecil tipe gelas yang tersedia di pasaran adalah 0,25 ampere, tapi kadang sulit didapat. Sekring ini hanya melindungi bagian tegangan tinggi saja, rangkaian di sebelah kiri transistor. Sedangkan bagian tegangan rendah tidak terlindungi sekring karena arus output yang sangat kecil yaitu sekitar 20 miliampere, sehingga jika terhubung singkat tidak akan memutuskan sekring.

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Pada prinsipnya rangkaian ini adalah rangkaian stabilisasi tegangan (voltage stabilizer) dengan dioda zener. Tegangan output tidak terpengaruh tegangan input, selama tegangan input lebih besar dari tegangan zener.

Tegangan input akan mempengaruhi arus maximal output. Semakin tinggi tegangan input maka semakin besar arus maximal yang dikeluarkan, sebaliknya jika tegangan input menurun maka arus maximal output mengecil. Jika beban membutuhkan arus di bawah arus maximal, maka saat tegangan input turun tidak akan mempengaruhi tegangan pada beban, atau tegangan output. Jadi rangkaian ini dapat bekerja pada tegangan 220 VAC dan 110 VAC. Untuk tegangan input 110 VAC, jika ingin menghasilkan arus maximal yang sama dengan tegangan input 220 VAC, maka nilai-nilai resistor RB and RC haruslah setengah dari nilai yang dijelaskan di bawah.

Dioda (D) saya gunakan jembatan dioda, karena sudah tersedia. Sebetulnya dioda-dioda tersebut harus disesuaikan dengan kapasitas arus dan tegangan. Bisa menggunakan 4 buah dioda 1N4007, yang mana mampu mengalirkan arus sampai 1 ampere dan tegangan maximal 1000 volt.

Kondensor 1 (C1) berkapasitas 1 mikrofarad dan harus mempunyai tegangan maximal diatas 220 volt. Saya gunakan yang bertegangan maximal 350 volt.

Resistor untuk basis (RB) menentukan arus yang diumpankan ke basis transistor. Saya gunakan resistor basis sebesar 390K, agar arus yang dikeluarkan dari emitor transistor sekitar 20 miliampere. Jika resistor basis dikecilkan, maka arus emitor akan semakin besar. Jika memperbesar arus emitor, pastikan transistor tidak terlalu panas. Jika tidak mempunyai thermometer untuk mengukur panas transistor, ada cara sederhana untuk mengetahui apakah transistor tidak terlalu panas, yaitu dengan menyentuh transistor dengan jari. Pastikan transistor tidak terlalu panas dan dapat disentuh jari setelah diberi beban satu menit. Sebelum menyentuh transistor dengan jari, pastikan tegangan tinggi sudah terputus.

Resistor untuk kolektor (RC) akan melindungi transistor dan beban jika arus naik melampaui batas. Saya gunakan resistor 10 kilo agar membatasi arus output atau emitor sekitar 20 miliampere. Resistor ini bisa diperkecil untuk memperbesar arus.

Dioda zener (DZ) menentukan tegangan output dari emitor. Saya gunakan zener 24 volt dengan daya 1/2 watt. Perlu diketahui bahwa tegangan output dari emitor transistor akan berkurang 0,6 volt. Sehingga jika menggunakan zener 24 volt, maka tegangan output akan menjadi 23,4 volt. Anda dapat menggunakan dioda zener yang sesuai dengan tegangan output yang dibutuhkan. Tegangan yang dihasilkan cukup stabil.

Transistor (T) adalah TIP50. Menurut spesifikasi dapat mengalirkan daya kontinue sampai 2 watt. Transistor ini mampu bekerja sampai tegangan kolektor-emitor 400 volt (Vceo). Penguatan arus (hFE) transistor ini pada rangkaian ini adalah sekitar 39. Perlu dipastikan spesifikasi dari setiap pabrikan pembuat transistor TIP50 yang anda gunakan. Transistor ini perlu diberi pendingin (heatsink). Walau untuk arus 20 miliampere dan tegangan output 24 volt tidak akan membuat transistor ini panas. Tapi karena bekerja dengan tegangan tinggi beresiko fatal jika terjadi kesalahan. Transistor ini rentan kepanasan (overheating) dan dapat pecah atau meletus dalam waktu kurang dari 1 (satu) detik, jika terjadi kesalahan perakitan yang menyebabkan pembebanan berlebih (overload) ataupun hubungan singkat. Pendingin transistor terhubung dengan kolektor sehingga bertegangan tinggi saat terhubung dengan jaringan listrik.

Jika dibutuhkan arus diatas 100 miliampere, maka dapat memasang transistor tegangan tinggi yang lebih besar seperti 2SC3527 yang dipasangkan secara Darlington. Pasangan Darlington adalah dimana ada dua transistor yang diparalel  kolektornya, basis transistor yang lebih besar disuplai oleh emitor transistor yang lebih kecil, output diambil dari emitor transistor besar. Pasangan Darlington diaktifkan dengan mensuplai arus pada basis transistor kecil. Dengan kata lain pada pasangan Darlington, transistor kecil mensuplai basis transistor besar agar arus yang dihasilkan jadi lebih besar. Tegangan output akan berkurang 1,2 volt dari tegangan zener jika menggunakan pasangan Darlington. Resistor RC dapat dikecilkan atau ditiadakan.

PERINGATAN: jangan menyentuh rangkaian saat terhubung dengan tegangan tinggi, pastikan anda menggunakan peralatan yang berisolasi listrik yang baik, pastikan sekring terpasang sebelum rangkaian dihubungkan dengan tegangan tinggi.

Karena sangat sederhana, rangkaian dapat dirangkai pada papan matrix.

Baca juga cara setrum aki mobil dengan cas laptop, sebagaimana foto berikut memperlihatkan aki mobil yang sudah berkurang tegangannya dan akan dicas dengan charger laptop.

## Tuesday, August 14, 2012

### Morning At The Edge Of Saguling Lake

This photo was taken around 7:00 am in Padalarang, West Java. This lake is part of the Saguling lake. Many dense trees can be seen around the lake. There is a plateau in the distance, it looks like it is Lembang plateau. In this lake there is a dam for an electric power plant that use hydropower renewable energy. This Saguling lake gets its water from Citarum river. The area around the lake is used for fisheries and agriculture. Without trees around the lake, Saguling will lack of water, lowering the production of electricity, and would no longer support the life and economy which are depend on it.

That morning was somewhat cloudy and quite cool, the air feels clean and fresh because of many big trees. Many people exercise on the street near the lake. Foggy air causes soft color and make the photo looks like painting.

In the afternoon a lot of people are sightseeing around the lake. In other parts of the lake, about 500 meters straight distance from this place, there a place for water skiing, which became a spectacle and free entertainment for the surrounding community.

Around the lake there is a real estate being constructed. Will this scene continue to be enjoyed?

Foto ini diambil sekitar jam 7:00 pagi di Padalarang, Jawa Barat. Danau ini adalah bagian dari danau Saguling. Tampak pohon-pohon yang masih rimbun di sekitar danau. Di kejauhan tampak dataran tinggi, sepertinya itu adalah dataran tinggi Lembang. Di danau Saguling terdapat waduk Saguling yang juga berfungsi sebagai pembangkit listrik yang menggunakan energi terbarukan yaitu tenaga air. Danau Saguling mendapat air dari sungai Citarum. Daerah sekitar waduk digunakan untuk perikanan dan pertanian. Tanpa pepohonan di sekitarnya danau Saguling akan kekurangan air, menurunkan produksi listrik, mematikan kehidupan dan ekonomi yang bergantung padanya.

Pagi itu agak berkabut dan cukup sejuk, udaranya terasa bersih dan segar karena banyaknya pepohonan. Banyak orang berolah raga di jalanan di dekat danau. Udara yang berkabut menyebabkan foto berwarna lembut dan seperti lukisan.

Di sore hari banyak yang bertamasya di pinggir danau. Di bagian danau yang lain, sekitar 500 meter jarak lurus dari tempat ini, digunakan untuk olah raga ski air, yang menjadi tontonan dan hiburan gratis bagi masyarakat sekitarnya. Di sekitar danau ini sedang dibangun real estate. Akankah pemandangan ini akan terus bisa dinikmati?

## Monday, July 16, 2012

### Front Brake Bleeding By One Mechanic Only

Procedure with photos and video described here is the work of my innovation and it is easy to apply and designed to be done by only 1 (one) mechanic. Tools needed are combination spanner, hose, and container for used brake fluid. At first glance this brake bleeding procedure is similar to the one that already exist. But by lifting the hose higher than nipple and using grease to prevent air enter the system, this procedure can be done by one person only. No need assistance (helper) to open and close nipple many times. With this procedure, brake air bleeding for one wheel can be done in just 15 minutes if no problems. Jack and remove the wheel can take longer time. On some high ground clearance vehicles such as jeep, this procedure can be performed without removing the wheel. Likewise, if you have car lift, brake air bleeding can be done without removing wheels. Because of easy, one with no experience can do it. You can do it in your garage at home.

See a video about three colorful origami boats are sailing together without: fuel, engine, battery, electric motor, and without wind blow. Boats are powered by chemical reaction to provide hydraulic energy.

Photo below shows a hose filled with new red brake fluid after brake bleeding. Used brake fluid is collected in a plastic bottle of mineral water.

In this article, brake bleeding is done for the front brake. To bleed air from the rear brake can be read in the article: Brake Bleeding Practical Procedure By Only One Mechanic.

There is also a simple procedure that uses a pump to push brake fluid in reservoir to go out from nipple. Also there is a procedure that uses a vacuum pump to suck brake fluid from nipple. Although easy, but both procedures require expensive equipment.

Video at the bottom of this post shows the clear brake fluid with air bubbles and red colored brake fluid that come out from brake nipple and go into the transparent hose. A new red brake fluid will replace the old clear brake fluid.

If you just done any repair on piston or cylinder on the wheel or the brake master cylinder (brake pedal cylinder), for example: replacement of rubber seals, it is necessary to bleed air from brake hydraulic system. Air trapped in the hydraulic system will cause no brake pressure. Brake pedal feel light and can be pressed to bottom, and feels like stepping on a balloon or rubber foam. This occurs because the physical properties of air that can be compressed (compressible) and shrink the volume. While the brake fluid can not be compressed (incompressible) or volume always constant even when under pressure.

The usual procedure is requiring two people. One person in charge of pumping the brake pedal until pressure build up, then hold the pedal in a depressed position. Another person is at the wheel to loosen nipple so the air can go out of the hydraulic brake system, and then immediately close nipple again. Brake pedal is then released and pumped again, and so on until the pressure is building up and normal, and pedal does not feel like stepping on a balloon anymore. This usual procedure is written on many websites.

In the video at the end of this article, the bleeding is performed to replace the old brake fluid with new brake fluid. Usually brake fluid is drained every 2 years, please refer to your vehicle service manual. Replacement of brake fluid needs to be done because of moisture or water entering the hydraulic system, and some other material such as: dirt, rubber seal debris, rust, air.

This procedure can also be used to bleed air after a major overhaul on the brake hydraulic system, such as replacement rubber seals in wheel cylinder or in the master cylinder. And can be applied to almost any vehicle using the hydraulic system for brake, including motorcycles.

Brake bleeding should be started from the wheel farthest from the master cylinder. In order for the air and the old brake fluid can get out in the large volume quickly. For cars with the driver position on the right such as Indonesia, Britain, Australia, Japan, Singapore, Malaysia, Hongkong, India, New Zealand, etc. the farthest wheel is the left rear wheel. On some cars, the position of the brake master cylinder is not right near the foot of the driver, on the right side for Indonesia. There are some European cars have master cylinder positioned on the passenger side. Maybe because those cars were originally designed with the driver's position on the left, but later modified to have the driver's position on the right to expand market share.

The first thing that needs to be done before bleeding the brake: open the brake fluid reservoir cap, check brake fluid level, top up to maximum is necessary. The photo below shows brake fluid reservoir pointed by red arrow. Smaller reservoir is for the clutch.

Clean outside reservoir with water, the reservoir is watertight and can be sprayed with water. Open the reservoir cap, the cap on some vehicles have two parts. In the photo below shows the tank cap is opened and still another cap on the inside.

Open the inside cap and attach to the outer cap. The inside cap prevents brake fluid to spill out but still allow air to enter or ventilation. Below photo shows the inside cap is attached to the outside cap. Note the clear Prestone brake fluid inside reservoir. Clear brake fluid will be replaced with a new red coloured brake fluid. Shown also in the photo the brake fluid is around the maximum level.

Jack and remove the farthest front wheel from the master cylinder, the left front wheel for Indonesia. Make sure the jack is securely positioned. Put the removed wheel under the car and add a block of wood to help jack. As the photos below.

Check for any trace of brake fluid, which indicates a leak and usually happen in piston caliper, nipple, and brake line connection.

Clean the left front brake and wheel well with water for easy and clean job. Shown in the photo below the front brake of disc type. On some vehicles the front brake is drum type, especially on the old car, bus and pickup truck.

The air bleeding valve is designated by red arrow in the picture above. Located on the inner side of the caliper, its rubber dust cap was removed to show the nipple.

Loosen the air bleeding valve with combination spanner. The front brake of this vehicle is using combination spanner of size 10 mm, use the one that suit your vehicle nipple. Avoid using an open end spanner to loosen and tighten the nipple, because open end spanner only holds two corners of nipple bolt head and can cause damage to nipple bolt head. In the photo below we can see how to loosen the nipple with ring part of combination spanner, the ring spanner holds to all corners of the bolt head nipple and prevent to damage bolt head.

No need to remove nipple, only loosen nipple to about 30 to 60 degrees of rotation. Usually there will be a drop of brake fluid if nipple is loosened to about 30 to 60 degrees of rotation. Tighten slightly to stop brake fluid drip as it needs to wait for the preparation and installation of hose and used fluid container.

Connect a transparent hose diameter 3/16 inch or 5 mm to nipple, as shown below. If the hose too small, it can be widened a little bit by heat in order to fit it to nipple. If the hose too big, then use a smaller rubber hose. As far as I know the smallest diameter of transparent hose is 3/16 inches. There are rubber hoses with smaller diameter, and rubber hose is far more flexible then plastic hose. But the rubber hose is not transparent so we cannot see and check if any air bubbles inside the hose. So if the nipple is too small, connect a rubber hose to nipple, and then connect that rubber hose to a transparent plastic hose. This way we can clearly see and check fluid inside the transparent plastic hose.

At a distance of about 50 cm from the end of the hose on nipple, tie a yarn. This yarn attached to the vehicle body with duct tape (adhesive tape) to make a loop The higher hose loop peak, the easier for air to come out of hydraulic system as air in brake fluid try to go up to higher place. The yarn does not block the view when we look at top of the hose where air bubbles are gathered. The other end of the hose is inserted into a container. Make sure the hose is not leaking. Leaking hose will allow air to enter the hydraulic system. A leaky hose can also spray brake fluid and damage car paint. Immediately flush with clean water if the paint sprayed with brake fluid.

In the picture above shows a hose is connected to nipple, hose goes up as it is hung by yarn and duct tape on the car body. The other end of the hose is inserted into a container of mineral water plastic bottle, make sure this hose end reach the bottom of container. As container is filled by used brake fluid, fluid will prevent air to get into transparent hose via container. This will ensure only air from hydraulic system gathered at top hose, this way it will be easier to check if there is still air in hydraulic system. Although air may enter hose via container, it can't reach nipple as air can't go down passing through brake fluid by itself. We can see air bubbles from hydraulic system will be gathered at top of the hose, nothing air from container, then air is pushed by pedal pressure down into container.

That rised hose will help to remove air bubbles from brake hydraulic system. Air, steam and other gases have physical properties that lighter specific gravity then liquids. Air, steam, and other gases in the hose will tend to go up to higher place when enter the hose together with brake fluid. So the air, steam and gases will 'go up by themselves' to get out of the brake hydraulic system.

Actual length of the hose is not necessarily the same length as the photo above. Since I will use that hose for other purposes, then I do not cut the hose.

To prevent outside air to enter the brake hydraulic brake system through some small holes (pores) around nipple, then apply grease around nipple and at the end of the hose that is attached to the nipple. See the photo below, green grease is pointed by green arrow. Seen also clear brake fluid had started out with some air bubbles, because nipple has been already loosened again about 30 to 60 degrees shortly before being photographed.

Clear brake fluid will be drained and replaced with red brake fluid. If there are air bubbles in the hydraulic system, the brake fluid in the hose will appear foamy or bubbly. Air bubbles will also be seen moving up as they try to get to a higher place in the hose. Ensure enough fluid in brake reservoir, top up with new brake fluid. The photo below shows Prestone red brake fluid is added. The red brake fluid is over maximum level. But because it will be drained, then the brake fluid level will be lowered by itself.

Get into the cabin and sit on the driver's seat. Make sure the parking brake is released, so that all brake wheel cylinders will react when you step on the brake pedal, and release the trapped air and dirt in the wheel cylinder. Press or pump the brake pedal 5 times, the pedal stroke is long as brake fluid and air go out of loosened nipple. No need to turn on the engine, as foot pressure is enough to pump the pedal. No need to open and close nipple many times.

If the brake fluid has not come out, loosen nipple again to about 30 degrees. Too loose nipple will cause too much brake fluid draining and emptying the reservoir, also causes the air easily enter from the gap around nipple thread.

After 5 times pumping the pedal, check brake fluid in reservoir tank, top up if it has reached a minimum level. Check nipple, hose and used brake fluid container on the wheel brake. Make sure there is no leak in the hose, especially on the connection between the hose to nipple. Fix hose connection and add grease if there are drops of brake fluid.

If everything is no problem, then move on and pump the brake pedal as much as 10-15 times. Do not do it in a hurry. Too many pumping will cause brake fluid reservoir empty and the master cylinder will suck air. Any air inside master cylinder will cause longer time to bleed the system.

For a sedan, usually 50-100 times pumping brake pedal is enough for each wheel to drain the old brake fluid and replace with new fluid. For air bleeding may need a little more pumping, especialy after major repair to master cylinder. Because air inside master cylinder must travel into all pipes and enter into wheel cylinders before it can get out of the brake hydraulic system.

The photo below shows the brake fluid after brake pedal pumped few times. Visible in the transparent hose, clear brake fluid with air bubbles go out first. Brake fluid and air can not re-enter the nipple and come into the wheel cylinder as there is a valve mechanism in the master cylinder that makes the master cylinder works like piston pump.

Then the brake fluid is changed to red. Different color brake fluid is used to to distinguish the old brake fluid from new brake fluid.

When brake fluid has been replaced with new one, shut nipple off with an open end spanner. Do not too tight as it can damage nipple bolt head.

Remove the hose and retighten nipple with ring part of combination spanner, do not too tight because it gets seized and difficult to be loosen in the future. Brake fluid will seal any small holes (pores) to prevent seepage, after sometime nipple will be more tightened like glued. Photo below shows nipple is tightened with a ring spanner, which is the ring part of spanner is used to tighten the nipple.

Put the dust rubber cap on nipple, clean and wipe all parts and area moistened and dripped by brake fluid. Cleaned and dried area will help to spot any fluid leaks. Reinstall wheel, and lower the jack. Do not forget to tighten wheel nuts criss-cross to ensure wheel is really centrist.

The following video shows brake fluid in the hose. At first clear Prestone brake fluid and many bubbles are going out, followed by Prestone red-colored brake fluid. At the end of the video shows nipple is closed by open end spanner. If you can not open this video, please open it on YouTube: Front Brake Bleeding By Only One Mechanic.

Proceed to the second farthest front wheel from brake master cylinder position, it is the right front wheel for cars in Indonesia. Run test your vehicle and brake suddenly to ensure brakes performance. Pedal will feel higher if the air and the old brake fluid are drained away, and do not feel like stepping on soft foam or baloon.

Used brake fluid should not be recycled, because dirt and water can change the nature of brake fluid, although the visual look is still clean. Because brake fluid also functions to clean the hydraulic system, the brake fluid is made to have same chemical properties as soap. It can dissolve the dirt and water, so it can not be filtered. Old brake fluid can be used as component cleaner, particularly components made of plastic and rubber that are not oil resistant.

Do not dispose carelessly as brake fluid can contaminate the environment, if swallowed in large quantities can be harmful to health.

## Friday, July 13, 2012

### Buang Angin Rem Depan Oleh Satu Orang Mekanik

Prosedur dengan foto dan video yang dijelaskan di sini adalah karya inovasi saya yang mudah digunakan dan didesain untuk dikerjakan oleh hanya 1 (satu) orang mekanik. Alat yang digunakan adalah kunci ring pas (combination spanner), selang, dan penampung minyak rem bekas. Secara sekilas mirip dengan prosedur buang angin rem (brake bleeding) yang sudah ada. Tapi dengan mengangkat selang lebih tinggi dari nipel dan menggunakan gemuk (grease) sebagai pencegah udara masuk, prosedur ini dapat dikerjakan hanya oleh satu orang. Tidak perlu bantuan (helper) untuk membuka dan menutup nipel berkali-kali. Dengan prosedur ini satu roda dapat dibuang angin remya hanya dalam 15 menit jika tanpa masalah, mendongkrak dan melepas roda dapat memakan waktu lebih lama. Pada beberapa kendaraan yang tinggi seperti jip, prosedur ini dapat dilakukan tanpa melepas roda. Demikian juga jika anda memiliki lift untuk mengangkat mobil, angin rem dapat dibuang tanpa melepas roda. Karena mudah, seorang tanpa pengalaman dapat mengerjakannya. Anda dapat mengerjakannya di garasi di rumah anda.

Foto di bawah ini memperlihatkan selang yang terisi minyak rem baru berwarna merah setelah pembuangan angin dilakukan. Minyak rem bekas tertampung di wadah plastik bekas botol air mineral.

Pada artikel ini dibahas pembuangan angin rem di roda depan. Untuk membuang angin rem di roda belakang dapat dibaca di artikel: Cara Praktis Buang Angin Rem Oleh Satu Mekanik

Ada prosedur yang juga mudah yaitu menggunakan pompa untuk menekan minyak rem di reservoir dan keluar dari nipel. Juga ada prosedur yang menggunakan pompa vacuum untuk mengisap minyak rem dari nipel. Walau mudah, tapi kedua prosedur tersebut membutuhkan alat yang mahal.

Gambar video di bagian bawah posting ini memperlihatkan minyak rem berwarna bening dan gelembung yang keluar dari nipel rem dan memasuki selang transparan. Selanjutnya minyak rem yang baru yang berwarna merah memasuki selang menggantikan minyak rem lama yang bening.

Jika baru saja dilakukan perbaikan pada piston atau silinder rem di bagian roda ataupun master cylinder (silinder pedal rem), misalnya penggantian karet seal, maka perlu dilakukan pembuangan angin dari sistem hidrolik rem. Udara atau angin yang terperangkap di dalam sistem hidrolik akan menyebabkan rem tidak pakem. Pedal rem terasa dalam sampai kandas saat diinjak, dan terasa seperti menginjak balon atau menginjak karet busa. Hal ini terjadi karena sifat fisika udara yang dapat ditekan atau dimampatkan (compressible) hingga volumenya mengecil, sedangkan minyak rem tidak dapat dimampatkan (incompressible) atau volumenya selalu tetap walau mendapat tekanan.

Karena sifat cairan seperti minyak rem, air, oli, dan lain-lain yang tidak bisa dimampatkan, maka dimanfaatkan untuk sistem hidrolik dengan tekanan sangat tinggi. Baca juga hidrostatik test bertekanan tinggi mencapai 1500 psi atau sekitar 50 kali tekanan ban, dengan memanfaatkan silinder kopling jip CJ7.

Adapun prosedur yang biasa digunakan, membutuhkan dua orang. Satu orang bertugas memompa pedal rem hingga terasa ada tekanan dan langkahnya jadi agak pendek atau lebih tinggi, lalu pedal ditahan dalam posisi tertekan. Satu orang lagi bertugas mengendurkan nipel rem di roda agar angin dapat keluar dari sistem hidrolik rem, kemudian segera ditutup kembali. Pedal rem dilepas dan dipompa lagi, begitu seterusnya sampai tekanan benar-benar naik dan pedal tidak terasa seperti menginjak balon lagi. Prosedur biasa ini banyak ditulis di situs internet.

Pada video pembuangan angin yang dilakukan dan dijelaskan di sini adalah saat menguras dan mengganti minyak rem lama dengan minyak rem baru. Biasanya minyak rem dikuras setiap 2 tahun sekali, harap merefer ke service manual kendaraan anda. Penggantian minyak rem perlu dilakukan karena adanya embun atau air yang masuk ke dalam sistem hidrolik rem, kotoran, sisa karet seal, karat, udara, sehingga perlu dikuras.

Prosedur ini dapat juga digunakan untuk membuang angin setelah perbaikan besar pada sistem hidrolik rem, misal penggantian karet piston di roda atau karet piston pada master cylinder. Dan dapat diterapkan pada hampir semua kendaraan yang menggunakan sistem hidrolik pada remnya, termasuk sepeda motor.

Membuang angin sebaiknya dimulai dari roda paling jauh dari master cylinder. Agar angin dan minyak rem lama dapat segera keluar dalam jumlah atau volume banyak. Untuk mobil dengan posisi pengendara di sebelah kanan seperti Indonesia, Inggris, Australia, Jepang, Singapura, Malaysia, Hongkong, India, New Zealand, dll. maka roda terjauh adalah roda belakang kiri. Untuk roda depan maka roda terjauh adalah roda depan kiri. Pada beberapa kendaraan, posisi master cylinder rem tidak tepat di dekat kaki pengemudi, yaitu di sebelah kanan untuk Indonesia. Ada mobil Eropa yang posisi master cylindernya di sebelah kiri atau di sebelah penumpang. Mungkin karena mobil tersebut awalnya dirancang dengan posisi pengemudi di sebelah kiri, tapi kemudian dimodifikasi menjadi posisi pengemudi di sebelah kanan untuk memperluas pangsa pasar.

Hal pertama yang perlu dilakukan sebelum rem dibuang anginnya adalah: buka tutup reservoir minyak rem atau tanki rem, periksa tinggi permukaan minyak rem, jika kurang maka tambah sampai maximal. Pada foto dibawah tampak tangki minyak rem adalah yang ditunjuk oleh panah merah. Tangki yang lebih kecil adalah reservoir minyak kopling.

Bersihkan tanki reservoir dengan air, tangki ini kedap air dan bisa disemprot air. Buka tutup reservoir, pada beberapa kendaraan tutupnya ada dua bagian. Pada foto di bawah memperlihatkan tangki yang terbuka dan masih ada tutup lain di bagian dalamnya.

Buka tutup yang di bagian dalam lalu pasangkan ke dalam tutup luar. Tutup di bagian dalam ini berfungsi mencegah minyak rem melimpah keluar reservoir tapi tetap melewatkan udara masuk atau ventilasi. Tampak di foto bawah tutup dalam yang terpasang pada tutup luar. Terlihat juga minyak rem Prestone yang berwarna bening. Minyak rem bening tersebut akan diganti dengan minyak rem berwarna merah. Tampak pada foto minyak rem masih pada sekitar level maximum.

Dongkrak dan buka roda depan yang paling jauh dari posisi pengendara, yaitu roda depan kiri untuk Indonesia. Pastikan posisi dongkrak yang aman. Masukkan roda yang terlepas ke kolong mobil dan tambahkan balok kayu untuk membantu dongkrak. Seperti foto di bawah.

Check jika ada jejak lelehan minyak rem yang menandakan adanya kebocoran, yang biasa terjadi pada piston caliper, nipel, dan sambungan saluran minyak rem.

Bersihkan rem dan spakbor roda depan kiri dengan air agar pekerjaan mudah dan bersih. Tampak pada foto di bawah rem depan dari tipe cakram. Pada beberapa kendaraan rem depannya dari tipe tromol, terutama pada kendaraan bus atau pickup dan kendaraan produk lama.

Katup buang angin (air bleeding valve) adalah yang ditunjuk oleh panah merah pada gambar di atas. Terletak di sebelah dalam caliper (klip, penjepit, cengkam), terlihat karet abunya sudah dilepas agar tampak nipelnya (nipple, puting).

Kendurkan dengan kunci ring pas. Pada rem roda depan mobil ini digunakan kunci ring pas (combination spanner) ukuran 10 mm, sesuaikan dengan nipel kendaraan anda. Hindari menggunakan kunci pas saat mengendurkan dan mengencangkan, karena kunci pas hanya memegang 2 sudut dari kepala baut nipel dan dapat menyebabkan kepala baut nipel rusak. Pada foto di bawah terlihat cara mengendurkan nipel dengan bagian kunci ring dari kunci ring pas, agar kunci memegang semua sudut dari kepala baut nipel dan mencegah kepala baut tersebut rusak.

Tidak perlu sampai melepas nipel, cukup dikendurkan sekitar 30 sampai 60 derajat putaran. Biasanya akan ada tetesan minyak rem keluar jika dikendurkan antara 30 sampai 60 derajat putaran. Kencangkan sedikit agar minyak rem tidak terus menetes karena akan menunggu persiapan dan pemasangan selang dan penampung minyak.

Pasang selang transparan diameter 3/16 inchi atau 5 mm pada nipel, sebagaimana gambar di bawah. Jika selang kekecilan bisa diperbesar sedikit dengan dipanasi agar melebar dan nipel bisa masuk. Jika selang kebesaran, maka gunakan selang karet yang lebih kecil. Setahu saya selang transparan tidak ada yang lebih kecil diameternya dari 3/16 inchi. Selang karet ada yang berdiameter lebih kecil, dan selang karet jauh lebih flexibel dari selang plastik. Tapi selang karet tidak transparan sehingga tidak kelihatan jika ada gelembung udara. Maka jika nipelnya terlalu kecil, pasang selang karet pada nipel lalu selang karet tersebut disambung dengan selang plastik transparan agar bisa dilakukan visual check pada minyak rem.

Pada jarak sekitar 50 cm dari ujung selang di nipel, ikatkan benang. Benang ini ditempelkan ke bodi kendaraan dengan lakban (adhesive tape). Semakin tinggi puncak selang maka semakin mudah angin keluar dari sistem hidraulik, karena angin di dalam minyak rem berusaha mencapai tempat lebih tinggi. Penggunaan benang dimaksudkan agar tidak mengganggu jika melihat ke dalam puncak selang di mana busa atau gelembung udara berkumpul. Ujung selang yang lain dimasukkan ke dalam penampung minyak rem. Pastikan tidak ada bagian selang yang bocor. Selang yang bocor dapat memasukkan udara ke dalam sistem hidrolik rem. Selang yang bocor juga dapat menyemprotkan minyak rem yang dapat merusak cat mobil. Segera siram dengan air bersih jika cat terkena minyak rem.

Pada gambar di atas terlihat selang yang terpasang pada nipel, selang naik ke atas karena digantung dengan benang dan lakban pada bodi mobil. Ujung selang lainnya dimasukkan ke dalam kontainer penampung dari botol plastik bekas air mineral. Ujung selang yang ini sebaiknya menyentuh dasar kontainer. Ketika kontainer terisi minyak rem bekas, maka ujung selang akan tertutup dari udara luar. Sehingga hanya angin dari sistem hidrolik yang terkumpul di bagian atas kontainer, dengan cara ini akan mudah dicheck apakah masih ada angin di dalam sistem hidraulik. Walaupun udara dari kontainer dapat masuk ke dalam selang yang terisi minyak rem, tapi tidak bisa masuk ke dalam nipel karena udara tidak bisa turun sendiri melewati minyak rem. Kita dapat melihat angin dari nipel berkumpul di bagian atas selang, tidak ada udara dari kontainer, lalu angin terdorong ke dalam kontainer oleh tekanan pedal.

Selang yang naik ke atas akan membantu mengeluarkan udara dari sistem hidrolik rem. Udara, uap, dan gas lainnya mempunyai sifat fisika berat jenis yang lebih ringan dari cairan. Udara, uap, dan gas-gas di dalam selang akan berusaha naik ke tempat yang lebih tinggi saat selang dimasuki oleh minyak rem. Maka udara, uap dan gas-gas tersebut akan 'berusaha sendiri' untuk keluar dari sistem hidrolik rem.

Sebenarnya panjang selang tidak perlu sepanjang seperti pada foto di atas. Karena saya masih akan memakai selang tersebut untuk keperluan lain, maka selang tidak saya potong.

Untuk mencegah udara luar masuk ke dalam sistem hidrolik rem melalui celah-celah nipel, maka oleskan gemuk (grease) di sekitar nipel dan ujung selang yang terpasang pada nipel. Lihat foto di bawah, gemuk berwarna hijau. Terlihat juga minyak rem berwarna transparan sudah mulai keluar dengan beberapa gelembung udara, karena nipel sudah dikendurkan kembali sekitar 30 sampai 60 derajat sesaat sebelum difoto.

Minyak rem yang berwarna bening akan dikuras dan diganti dengan minyak rem berwarna merah. Jika terdapat gelembung udara pada sistem hidrolik, maka minyak rem di dalam selang akan tampak berbusa atau berbuih. Gelembung udara juga akan tampak bergerak naik karena berusaha mencapai tempat yang lebih tinggi di dalam selang.

Pastikan tinggi minyak rem di dalam tanki reservoir, tambah minyak rem dengan yang baru. Di foto di bawah tampak minyak rem Prestone berwarna merah ditambahkan. Sebenarnya tinggi minyak rem merah sudah melebihi dari tinggi maximal. Tapi karena akan dikuras, maka minyak rem akan berkurang sendiri nantinya.

Masuk ke kabin dan duduk di kursi pengemudi. Pastikan rem parkir tidak bekerja, agar semua silinder rem pada roda dapat bereaksi saat pedal rem diinjak, dan melepaskan udara dan kotoran yang terjebak di dalam silinder roda. Injak atau pompa pedal rem 5 kali, pedal akan terasa dalam karena minyak rem keluar dari nipel yang kendur. Tidak perlu menyalakan engine, karena tekanan kaki sudah cukup untuk memompa pedal. Tidak perlu membuka dan menutup nipel berkali-kali.

Jika minyak rem belum keluar, kendurkan lagi nipel sekitar 30 derajat. Nipel yang terlalu kendur akan menyebabkan minyak rem mengucur terlalu banyak dan cepat mengosongkan tanki, juga menyebabkan udara mudah masuk dari sela-sela ulir nipel.

Setelah 5 kali pedal dipompa, periksa minyak rem dalam tanki reservoir, tambah jika sudah sampai level minimal. Periksa nipel, selang dan penampung minyak rem di roda yang dikuras minyak remnya. Pastikan tidak ada kebocoran pada selang, terutama pada sambungan antara selang dengan nipel. Perbaiki sambungan selang dan tambahkan grease jika ada tetesan minyak rem.

Jika semuanya tidak ada masalah, maka lanjutkan menginjak pedal rem dan pompa sebanyak 10-15 kali. Jangan lakukan tergesa-gesa. Jika terlalu banyak memompa, minyak rem di tanki reservoir bisa habis dan master cylinder akan mengisap udara. Jika master cylinder mengisap udara maka pembuangan angin akan lebih lama dilakukan.

Untuk mobil sedan biasanya memompa atau menginjak pedal rem 50-100 kali untuk setiap roda sudah dapat menguras minyak rem lama dan terganti dengan yang baru. Untuk pembuangan angin bisa agak lebih banyak memompanya, terutama setelah perbaikan besar pada master cylinder. Karena angin yang masuk ke dalam master cylinder harus berjalan ke semua pipa dan menuju silinder di roda-roda sebelum dapat keluar dari sistem hidrolik rem.

Foto di bawah memperlihatkan minyak rem yang dipompa dengan menginjak pedal rem berulang-ulang. Di dalam selang transparan, mula-mula keluar minyak rem berwarna bening bersama gelembung udara. Minyak rem dan udara tidak bisa kembali masuk ke nipel dan ke dalam silinder roda ataupun sistem hidrolik rem karena ada mekanisme katup pada master cylinder yang membuat master cylinder bekerja seperti pompa piston.

Lalu minyak rem berganti menjadi berwarna merah. Warna minyak rem yang berbeda berguna sebagai tanda untuk membedakan minyak rem baru dan minyak rem lama. Minyak rem berwarna merah tampak di foto di atas mengisi selang.

Jika minyak rem sudah berganti dengan yang baru dan tidak ada lagi gelembung udara dari nipel, tutup nipel dengan kunci pas. Jangan tutup terlalu kuat karena kunci pas dapat merusak kepala baut nipel. Kunci pas dapat memegang kepala baut nipel walau selang masih terpasang pada nipel.

Lepaskan selang dan kencangkan nipel dengan kunci ring, jangan terlalu kencang karena akan macet dan sulit membukanya di kemudian hari. Minyak rem akan menutup setiap sela dan lubang kecil (pori-pori) guna mencegah rembesan, dengan berjalannya waktu nipel akan semakin kuat terpasang seperti lengket atau dilem. Foto di bawah memperlihatkan nipel dikencangkan dengan kunci pas ring, yang mana bagian kunci ring yang digunakan untuk mengencangkan nipel.

Pasang kembali karet abu pada nipel, bersihkan dan lap semua komponen yang terkena minyak rem. Dengan bersih dan keringnya area yang terkena minyak rem maka akan mudah terlihat jika ada minyak rem yang menetes. Pasang roda, dan turunkan dongkrak. Jangan lupa untuk mengencangkan baut roda secara silang agar roda benar-benar sentris.

Video berikut memperlihatkan minyak rem di dalam selang. Mula-mula tampak keluar minyak rem Prestone berwarna bening dan banyak gelembung udara, lalu diikuti dengan minyak rem Prestone berwarna merah. Pada akhir video terlihat nipel ditutup dengan kunci pas. Jika anda tidak bisa membuka video ini, harap membuka di YouTube: Buang angin rem depan oleh satu mekanik.

Lanjutkan ke roda depan terjauh kedua dari posisi master cylinder, yaitu roda depan kanan untuk posisi sopir di kanan seperti pada mobil di Indonesia. Uji kendaraan anda dengan menjalankan dan rem mendadak untuk memastikan kinerja rem. Pedal akan terasa lebih tinggi jika udara dan minyak rem lama sudah terkuras habis, dan tidak terasa lunak seperti menginjak busa atau balon.

Minyak rem bekas jangan didaur-ulang, karena kotoran dan air dapat mengubah sifat minyak rem, walau secara visual terlihat masih bersih. Karena minyak rem harus membersihkan sistem hidrolik rem, maka minyak rem dibuat mempunyai sifat kimia seperti sabun, dapat melarutkan kotoran dan air, sehingga tidak dapat disaring. Minyak rem bekas dapat digunakan sebagai pembersih komponen, terutama komponen yang terbuat dari plastik dan karet yang tidak tahan minyak.

Jangan membuang minyak rem sembarangan karena dapat mencemari lingkungan, jika terminum dalam jumlah banyak dapat membahayakan kesehatan.

## Saturday, July 7, 2012

### Rain Tree Overshadows Various People To Earn A Living

Rain tree (Albizia saman, Samanea Saman) the world's largest oxygen producer, overshadows many people to earn a living, such as: motorcyclist, tire repair shop, shop, cafe, restaurant, minimart. There is an orange and white minibus of Pos Indonesia parks and serves there. Photographed during lunch time, seen the writings of 'POS' at the closed back door of minibus. When busy people get together and lining up around the minibus, if photographed it does not appear that the minibus is a mobile post office.

Someone with blue shirt is repairing motorcycle tire on the right of post office minibust. At dawn many taxi-cab are parked and waiting for passengers to Jakarta from Cinere, Depok, Pondok Cabe, and surrounding areas. Some taxi drivers say that they spend the night under that rain tree as they are late to go home, and hope for the passengers in the morning. When scorcher, a lot of people take shelter under this tree while waiting for public transport.

Under this tree, It used to be a terminal for bus Patas P-18A Pondok Labu - Grogol. Before 6:00 am, many people were waiting bus under the tree. The first bus left at 6:00 and always full. There were no permanent buildings under this tree. There are only simple food stalls for students and employees of the Universitas Pembangunan Nasional, banks, hospital, private office, and Armed Forces from the surrounding neighborhood.

As far as I know there has never been a broken branch, although the tree grows to the side and sheltering a large area. Hopefully it will not happen.

May be the tree needs to be trimmed, but not to be cut. It's good to clean the area around the tree and laid out to avoid to become a slum area and continue as a shelter for various people, continue to produce oxygen, and helping turn the economy. Development does not have to sacrifice nature.

Pohon Trembesi (Albizia Saman, Samanea Saman) produsen oksigen terbesar dunia menaungi berbagai kalangan mencari nafkah, seperti: ojek, bengkel ban, warung, warnet, restoran, minimart. Ada minibus putih oranye Pos Indonesia diparkir dan melayani di situ. Difoto saat jam istirahat, terlihat tulisan ‘POS’ dan ‘bayardi’ di pintu belakang minibus yang tertutup. Saat sibuk orang-orang berkumpul dan antri di sekitarnya, jika difoto tidak kelihatan bahwa minibus tersebut adalah kantor pos berjalan.

Seseorang berbaju biru memperbaiki ban sepeda motor di kanan mobil pos. Saat subuh taxi-taxi mangkal menunggu penumpang tujuan Jakarta dari Cinere, Depok, Pondok Cabe, dan sekitarnya. Beberapa sopir taxi mengaku bermalam di bawah pohon ini karena telat pulang, dan berharap mendapat penumpang esok paginya. Saat panas terik banyak orang berteduh di bawah pohon ini sambil menunggu kendaraan umum.

Dulu di bawah pohon ini dijadikan terminal bus Patas P-18A Pondok Labu - Grogol. Sebelum jam 6:00 pagi, sudah ramai orang menunggu bus di bawah pohon. Bus pertama berangkat jam 6:00 selalu penuh sesak sampai berdiri. Dulu tidak ada bangunan permanen di bawah pohon ini. Hanya ada warung-warung sederhana untuk mahasiswa dan karyawan dari Universitas Pembangunan Nasional, bank, rumah sakit, swasta, dan Hankam/TNI di sekitarnya.

Setahu saya belum pernah ada dahan yang patah, walau tumbuhnya melebar ke samping menaungi wilayah yang luas. Semoga tidak akan terjadi.

Mungkin perlu dipangkas, tapi semoga tidak perlu ditebang. Ada baiknya area sekitar pohon dibersihkan dan ditata agar tidak kumuh dan tetap menjadi tempat bernaung berbagai kalangan, terus memproduksi oksigen, dan membantu memutar ekonomi. Pembangunan tidak harus korbankan alam.

## Friday, July 6, 2012

### Guide Choosing And Buying Digital Camera

Photo cameras are still popular although high-tech video cameras are already available at affordable prices. Strange phenomenon if we consider the logic. But when viewed from the side of art, this phenomenon is still acceptable. Art of photography can not be replaced by video, although video is very similar to the original event as it has moving images and sound.

I have learned photography as my hobby since I was in high school. Some of my photos are published in this blog with label "intermezzo".

How do we choose the right camera? First of all consider your needs. Do you need moving images and sound or video image, or simply capture the moment with a photo camera.

I prefer to use a video camera, especially when capturing events or moments that take place continuously, such as weddings, birthdays, sporting events, and others. Those moments take place quickly and continuously, and we can not capture one by one. So by using a video camera, we can record every moment continuously. And then replay to see which moments are the best. By seeking out the best moments of recorded event, then we can get best frames to become photos. Some digital photo camera can also record video with excellent quality and length up to several hours.

Currently various types of digital cameras available on the market at very affordable prices. Even the digital camera is bundled with other devices such as mobile phones and tablet computers.

Types of Photo Camera
There are three types of photo camera, that are: pocket, prosumer and DSLR (Digital Single Lens Reflex). If you intend to carry the camera with ease wherever you go, then pocket type camera is suitable for you. Pocket-sized camera is small and easily stored in the pocket. It is lightweight and does not feel heavy in your pocket. The price also will not make you feel heavy to your pocket. That is why so-called pocket camera.

If you want to create a sophisticated picture with high technique, DSLR camera is suitable for you. You can replace the camera lens with different type of lenses to suit every moment to be captured. The resulting image has a high resolution level reached 36.3 megapixels, so it can be enlarged to poster size, even can be printed for wallpaper size. DSLR camera can have different features and settings that can be tailored to your needs, such as setting: shutter speed, aperture diaphragm , ISO, and others. Various accessories for digital SLR cameras available for every shooting needs, to enable to produce the best image.

The term Single Lens Reflex is to explain that the viewfinder is looking through the same lens with the lens used to take picture or so-called Single Lens. This allows the image is produced with the exact same scene viewed when aiming the camera. Viewfinder of SLR camera use a mirror to reflect light from lens to view through that lens. The mirror will quickly folded up when the photo is taken, this to allow the light from the object comes into the lens and to the film, the mirror movement is like a reflex movement. This is why it is popularly called Single Lens Reflex. And because the film is changed with digital system, then added the word and become Digital Single Lens Reflect or DSLR. Lens of SLR camera can be replaced easily with many different types, and the viewfinder is always seeing through the same lens with shooting lens. Now the digital SLR no longer use a reflector mirror that can move quickly. There is only a viewfinder screen and large additional screen that receives the image through the shooting lens. Just an opinion: maybe the name can be changed to ‘Digital Interchangeable Lens camera’. The figure below are DSLR cameras available at Amazon.

The prosumer camera is the type of camera which has ability between pocket camera and DSLR. The price is affordable and comes with a fairly sophisticated zoom lens and features that exceed the pocket camera. Below are digital cameras from Amazon with affordable price.

There is a type of camera called the Compact System Camera (CSC). This type combines a pocket camera with a DSLR, may be included in the prosumer class. CSC camera lens can be replaced like a DSLR camera. Another name for CSC camera is mirrorless camera, because this camera has no longer used a mirror to see from the viewfinder like DSLR. Because it combines compact camera and DSLR, the CSC camera is also called hybrid camera. CSC camera can record images with almost equal quality with a DSLR camera. Some photographers say that CSC can replace DSLR camera in the future. But currently CSC lenses availability are not as many as for DSLR. And because of different lens mounting, DSLR lenses can not be used for CSC.

Flash
Photo camera does have more facilities than the video to produce better still image. The main facility is the flash, which obviously can not be rivaled by the video. With flash we can make good photographs with less light or even dark.

Some camera have the red-eye reduction capability by turning on the flash before the photo is taken, and then turn on the flash again when the photo is taken. Light from flash is reflected by open wide eyes pupil causing eyes appear red when photographed. Light entering eyes through wide open pupils, light is reflected and passed through blood vessels makes eyes look red. By turning on the flash before the photo was taken to make eyes to adapt with the flash light and smaller pupils to minimize flash light reflection.

If you need to take pictures in low light without flash, then you need to test the camera before you purchase it by pointing to a dark place, for example in a dark corner of the camera store. There are cameras that can be tuned its ability to capture light, called ISO. The higher the ISO the more sensitive to the light. But the higher the ISO value, the lower the sharpness of the image due to the reduced number of pixels.
Some video cameras can be used to record with only starlight, but the picture quality is not very good. Usually the video image is green, when used with low light recording. You can make photo in the dark without flash with this video camera.

There are trail cameras available today that can be used to shoot automatically if there are objects, humans, or animals are passing in front of the camera. Trail camera usually is used to monitor security, photographing wild animals, and others. Trail camera is equipped with the ability to record at night. Also equipped with an infrared lamp as a light for night vision, the light is invisible to the human eye but visible to the camera. Trail cameras have very affordable prices, please check to Amazon stock below.

Zoom lens
Zoom lens is an adjustable focal length lens, in other words can be used as a telephoto lens to zoom in or to make objects look closer, and can also be used with normal focal length to view like real distance to objects. If set at telephoto position, the zoom lens will make distant objects closer, and narrow angle of view. If set to a normal focal length, the zoom lens will capture the scene or object like our eyes see the scene or objects, that is the normal angle of view. Some of the zoom lens can be set for a wide viewing angle (wide angle) and can be used to photograph the vast landscapes, but the resulting picture is somewhat curved, for example: the horizon line does not look straight but curved.

If a still camera equipped with zoom lenses that can be operated manually, not electronically with button, then we can make a photo with zooming effect. The resulting image looks like brush strokes from the center to the outside, it looks as if the object explodes when photographed.

There are two types of zoom capability: optical zoom and digital zoom, total zoom is a combination of both. Usually the seller describes only the total zoom. Actually we do not really need digital zoom, it is performed by an electronic or digital, and it can be done with the computer when we do digital editing. Weakness of digital zoom that it will lower the image quality when the zoom is too big. So we better rely to the optical zoom, the zoom that can be done by the lens, optical zoom doesnt lower image quality.

It should be noted that the camera with high zoom ability is sensitive to camera shaking. The recorded image will appear bluring when using high zoom and camera was shaking. These are effects that occur in telephoto lenses, where the point of view so narrow, and the distant objects looks closer. Little movement on the camera, eg a few millimeters, will create an object in distant move a lot, like moving a few meters as magnified by tele lens. So to prevent this you need to practice how to hold the camera zoom lens. The use of support such as tripod and monopod would be helpful. Tripod and monopod used by cameramen who are covering sports such as football matches. They have to capture moments from a distance of tens of meters and had to be enlarged with a telephoto lens or zoom, so monopod or tripod will prevent image shaking. Some cameras with powerful zoom lens, have digital feature to reduce the effect of camera shaking.

Some cameras are designed with a pistol grip model as the photo below, such as Sanyo, Panasonic, Polaroid, Aiptek, DXG, Spectra, SVP, and others. Cameras of this type are proofen to have less shaking as better grip by the hand. Suitable for use for outdoor activities such as sporting events, camping, and others. Some cameras are not designed with a pistol grip, but can be attached with a pistol grip handle that can be purchased separately.

Screen
The screen on the camera helps to manage the composition while shooting. Some cameras are equipped with a viewfinder in addition to having the screen, because the screen use much battery power. So if you need to save battery power, then use the viewfinder.

I prefer the screen with flip type as it can be positioned to help us to look at the screen. There is a flip screen that can be directed to the front of the camera, so you can photograph yourself and adjust the composition by looking at the screen from the front of the camera. Photo above shows the type of camera with flip screen is rotated to front, photographed facing the mirror, note the same hand and the same camera on the screen.

The screen also helps to see the results of shooting so we can retake the photo if the results are no good. With screen you can review and delete wrong photos in order to save memory. Some cameras have a photo editing features, you can edit photo with the help of this screen.

Resolution
Sharpness or resolution of the image depends on dots or pixels that were recorded by camera software. The more pixels the better, but it will creat big image file and needs large memory. For a postcard-sized photographs measuring 3.5 x 5 inches or 89 x 127 mm, and it is called the 3R size, 3 megapixel camera is good enough. Today they are pocket cameras with more than 10 megapixels sharpness.

If you intend to make a detailed documentation for a natural scenery that can be enlarged, for example: you have to take picture of a hill with a variety of fruit trees. Later that photo will be used as documentation, and viewers can magnify images of that photo to see detail of trees on the hill and then enlarged again to see detail fruits on those trees. Then you need a camera with a very high resolution. Likewise, if you have to make landscape photos, model girl photos, etc., which will be printed very large, for example: to be affixed to a wall as wallpaper.

Battery
Some cameras can use common dry batteries that are available on the market, this type can also use rechargeable batteries that are available on the market. Some other camera use a special battery that can be recharged, these type of cameras can only use batteries designed for them. Choose the safest camera for you for long term use, do not rely on a cheap one but then you can not buy new battery.

Other Tips
Choose a digital camera that uses a storage container such as memory cards which are common in the market where you are. So you do not have trouble to add storage capacity. Choose a camera that uses a popular system to make it easy to share and print photos. You also need to ensure that the camera system does not conflict with your computer system. So you can store, display, edit, and print photos by your computer and your printer. Make sure the cable connections, such as USB, can be connected to your computer.

Today there is waterproof camera that can be brought to dive to depths of 12 meters or more. This waterproof camera is available with pocket type at a price slightly more expensive than ordinary pocket camera. This camera is also designed for shock resistant (shockproof). Suitable for covering activities in the wild.

And lastly, of course you have to choose a digital camera that suits your financial capabilities. Do not buy a sophisticated and expensive one as it’s technology could be obsolete within a few months, unless you really need the technology. You better buy the popular and not too expensive one. Because if many people are using it, it will be easy to share pictures, discuss with other camera users, easy to get accessories, and easily be repaired if damaged. If you want to resell it, the demand is hight so the price is not down too much. Popular products are usually have an easy and good warranty service.