How to make use of old PC power supply

I have 3 of those old power supply. At least 2 of them still works.Here is how to make use of the thing for power supply for other purposes.

This power supply has 5volts, 3volts, 11 (or 12?) volts and -11volts power. This is nice for electronics projects. For example, some IC's like the DAC requires negative voltage. It is available here without having to buy negative voltage generator.

Best of all, electronics dedicated power supplies costs at least RM100 or usually more. But in this case it is much cheaper. RM50?

The trouble is when you simply hookup this power supply to the 230volt supply,it will not work. Here is the trick that would make it work.

The black wire is ground. Using a multimeter, check each connectors and you'll find at least one wire with 3V and one with 5 V.

Most of the wires are red, black or orange. The other colours are one each.

Using 1kohm resistor, connect the 3V line to the other wires (not the red or black)one by one while monitoring the voltage across the black and redwire. Best to try connect the unique colour wires first to the 3 volt line. When you register 5 volts(or 12volts) across the black and red wires,the power supply unit is ready to go.

In my case, the 3 volt wire is green, and need to be connected to white wire for the power supply to work. Now I am off to do some projects..

Racial Relation

Baru-baru ini Negara digegarkan dengan tuntutan untuk kesamarataan antara kaum. Ini diikuti oleh tuntutan balas untuk ketuanan Melayu dan memperthankan perlembagaan Negara. Buat kesekian kalinya artikel 153 perlembagaan itu disentuh banyak pihak. Mujurlah ada Raja-Raja Melayu yang bersuara menegur rakyat agar tidak berlebihan dalam membincangkan isu yang tentunya amat sensitive ini. Peranan Raja yang beginilah yang akan mengangkat martabat institusi raja di Negara ini. Selepas teguran Baginda, nampaknya tiada siapa yang berani menyentuh isu ini lagi.

Namun aku rasa perkara ini perlu terus dibincangkan tetapi secara tertib dan objektif. Aku boleh faham dengan ketidakpuasan hati masyarakat bukan melayu terhadap ‘preferential treatment’ terhadap kaum melayu. Kalau kita lihat generasi baru bukan Melayu mereka bukan sahaja merupakan anak kelahiran Negara ini, tetapi yang entah telah beberapa generasi lahir di sini . Yang mereka tahu inilah satu-satunya tanah tumpah darah mereka. Dan disinilah juga kasih merreka akan tertumpah. Walaupun mungkin ada segilintir yang terlampau kecewa dan mahu berhijrah, tapiaku rasa lebih ramai yang akan setia dengan Negara ini. Sebahagian besarnya tidak pernah pun menjejakkan kaki ke tanah asal nenek moyang mereka itu.

Apabila mereka rasa mereka telah dilayan sebagai rakyat kelas kedua, tentunya ini akan menimbulkan rasa tidak puashati. Namun apakah benar wujud layanan kelas kedua ini? Ini perlu kepada penilaian yang objektif. Apakah falsafah yang mendasari ‘preferential treatment”ini? Kenapakah dasar ini menyebabkan rasa layanan kelas kedua ini wujud? Apakah dasar ini yang perlu dipersalahkan atau perlaksanaannya?

Aku seorang Melayu. Walaupun mungkin ada yang pernah menyangka aku mamak restoran MegahMaju di Nilai ini. Namun aku Melayu.. Sebagai Melayu aku juga ingin supaya bangsa aku mampu bersaing dengan yang lain.Aku juga tidak mahu melihat bangsa aku selamanya bergantung kepada preferential treatment ini. Aku malu kalau jadi melayu yang tidak kompetitif dalam segala bidang. Aku mahu satu hari bangsa Malaysia ini bersaing atas dasar merit. Siapa kuat bekerja dia dapat. Inilah utopia nya. Siapa kuat bekerja dia dapat. Tapi benarkah begitu? Apakah realitinya? Itu nanti kita bincangkan lain kali….. This is me thinking aloud. Kalau ada sesiapa yang membaca dan ingin turut “thinking aloud’ dipersilakan……

Still Alive...!

Man...! It has been 2 years since the last time I tried to write something.

Actually I did complete part of the robot. However, my computer went out of order and I lost all the source codes, pictures and everything. The BASIC STAMP was also damaged, for reasons I couldnot understand. And I had already dismantled the project.

This blog is actually meant as a medium for me to document all my doings. Hence I will try to put something on the robot project as well as other projects. There were also several other projects that I completed during this past years. The robot car, the stroboscope using LEDs, engine rpm counter/display (on laptop), engine lambda reader and water pump (hand operated) using PVC pipes.

First on the robot toy car project.

As I can remember it the following are the items used.
1. BASIC STAMP as the main controller (I don't know the price, maybe a few hundreds ringgits. There is cheaper option, using PIC microcontroller. PIC16F676 would be appropriate for RM9 only - 1k program memory, ADC, 12 IO ports)
2.L293D for motor driver (RM13)
3. light sensitive resistor. I don't know the porper name of this thing.... oh ya photoresistor?
4. resistors (RM0.05each)
5. capacitors(RM0.30 each)
6. breadboard for constructing thecircuit (RM15)
7. The RC car. battery operated. (RM50?)

One of the trouble with the operation was that the motor (DC motor) was quite powerful and draw a lot of current. The battery pack need to be adequate. I remember using 2 separate source of power for the STAMP and the motor. Otherwise the motor would draw so much current that the STAMP stopped working.

The other issue was the turning radius of the car. This made it to lost track of the light easily. In most wheeled robots, the robotcan turn on its axis and face the light. The way I overcame this is by having the car to make very fast three point turns everytime it sense that the light was lighter on one side. It is fun to see it making small three point turns in very rapid movement. Effectively one can see the robot to shake and turn towards the light source.

Unfortunately all the source codes were missing. I will see whether I can salvage the source codes from my old hard disk and post it here.

Next post will describe the toy car, its drive motor and the steering system.

Robot building: 1st post

Okay, this is my real 1st post.

I’ve promised my son that I’ll show him how to make an autonomous robot by the time he reach 9. That was 2 years ago. Now he is almost 10. That promise was never fulfilled.

Guilty conscious, I have scrambled for the past several months to find ways to get it done. Luckily, I saw one advertisement for a workshop on robot building for 9-12 year olds during one of the school holidays. I sent my son, and his cousin, for that one day workshop. It cost me RM125. There, they were taught how to build robots by using the LEGO Mindstorm set. Interested, I asked the instructor how much it would cost to buy one of those sets.. RM3000! I later asked Sasbadi (the agent for LEGO Mindstorm in Malaysia) and found that the minimum set would cost me around RM2000!

I feel that it was too expensive. And I was convinced that to make the robot from scratch would be more fun.

Electronics is not my area, let alone robotics. However, I was determined to learn and build one on my own. I own one Parallax Basic Stamp2 microcontroller, which I bought six years ago. One good thing about Parallax is that they have good website with a lot of information. They also have robotics teaching modules for their Board of Education single board computer (?). That would be useful.

Here is the plan for the robot that I would like to make. I used a cheap radio control car as the base with all the drive motor, steering motor, wheels, and the chassis. This cheap RC car employs DC motors only. There is no servo motor. I will have to figure out how to drive this motors.

Since it is based on a RC car, I need to figure out how the robot would have to maneuvre e.g. through obstacles etc. with a slightly different technique as opposed to using 2 servo motors.

I plan to have photo sensors to make the robot either folllow or run away from bright light.

I will put the detail of the parts list in the next post.

First Post...

Coming up next.....

plan, parts list, construction and experience of my first robot ... kalau projek tak terbengkalai lagi la.....