Thursday, February 14, 2013

Programmable Fridge Timer

Somewhere in February of 2013, my dad ask me to build him a timer for fridge, that turns on 3 times a day, i.e. 1 hour on, 7 hours off. The fridge temperature regulating mechanism failed, causing it to run entire day, consuming too much energy and money.

Get excited, I surveyed online for small PIC microcontroller. After all ordered component arrived, I kickstart the project quick. :)

I'm using cheap PIC10F220 6-pin mcu and 40A automotive relay for the project. Most of the circuit are for power supply and relay triggering.

The relay contacts are equipped with capacitive snubber for arc-suppression, enhancing relay's life.

Firmware is coded with XC8 compiller in MPLABX, running forever-loop of delays.

The 3 lower GPIO used for driving the relay, the relay-status LED, and running-LED.
It comes with power-up 3 seconds delay.

Designing component layout.

Done, but untested.

And it works! :) 

The white LED for running-indicator, it blinks every second, for 500ms. The green LED for relay status indicator.

Fully enclosed, and running, notice the reset button, tied to the PIC MCLR.

Final result, with 12 inches connect cable.

It feels good when you could lighten your dad's burden, it may not much, but it's more than nothing. ;)  

Probing Electrical Signals on the Bike

On 5th Feb 2013, we planned to probe some signals on the project bike, for some reason, both of us, Sudirman and I are busy with other academical assignments, so, we had to postpone our progress.

However, albeit with very limited time, we managed to find the bike's CDI inside its gut.

Front view.

Back view.

Side view.

I even found appropriate diagram from the net on the CDI. Here it is:

Image courtesy of

On 14th Feb 2013, Sudirman helped me to disassemble the bike again....

He's working on it.

All disassembled plastics.

While I'm supposed to only take some electrical signals on o'scope on that day, but hey, why not just fix the brake tail light when you can? :)

The LEDs are trolling...

Back view.

When you have a thousand of LEDs, why not change it all? :)

Now, we're all happy...

 Before proceeding probing those signals, I decided to lean out the AFR a little bit...

Here's the piston-valve with needle-valve removed.

Probing with engine idling.

At low RPM. Yellow trace is the reluctance sensor output, blue ones is alternator output.

At high RPM.

Here's a video for better detail.

Here's the CDI output signal.

After every desired signal probed, I thought, lets make our project a bit more complex with the addition of Gear-Position-Indicator (GPI)! ;)

Signal tapped directly at the connector.

Nothing fancy, it's just a 5-switch controlled LEDs.

Thanks to these two sites for the encouragement:

Wednesday, February 13, 2013

Ordered Components Arrived :)

On 31st Jan 2013, we received our ordered electronic components from RS, Element14, Lelong, and DHgate, all simultaneously... :)

Just get it back home from warden's office.

HV fast diodes.


New UT120C multimeter:)

1000 white LEDs!

On 3rd Feb 2013, Olin, Hatin, Haidar, and I go to Pudu Pasar Road again, somehow, only I'm the one that is shopping on that day... :) Many thanks to them for driving me there... 

These two transformer will hopefully producing 1kVDC; series'ed together.