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.

#include <xc.h> #include <pic10f220.h> #pragma config IOSCFS = 4MHZ // Internal Oscillator Frequency Select bit (4 MHz) #pragma config MCPU = OFF // Master Clear Pull-up Enable bit (Pull-up disabled) #pragma config WDTE = OFF // Watchdog Timer Enable bit (WDT disabled) #pragma config CP = OFF // Code protection bit (Code protection off) #pragma config MCLRE = ON // GP3/MCLR Pin Function Select bit (GP3/MCLR pin function is MCLR) #define _XTAL_FREQ 4E6 unsigned int RAM=0; void picInit() { GPIO = 0; ADCON0 = 0; OPTION = 0xC8; OSCCAL = 0x18; //Calibrated with Rigol DS1102E on 3Feb2013 TRISGPIO = 0; __delay_ms(3000); //delayed on } void delay1h() { for(int x=0; x<3600; x++) { __delay_ms(500); RAM &= 0xFB; GPIO = RAM; __delay_ms(500); RAM |= 0x04; GPIO = RAM; } } void main() { picInit(); RAM = 0xFF; GPIO = RAM; while(1) { for(int y=0; y<1; y++) //ontime { delay1h(); } RAM &= 0xFC; GPIO = RAM; for(int z=0; z<7; z++) //offtime { delay1h(); } RAM |= 0x03; GPIO = RAM; } }

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: http://www.chinese-parts-canada.com/wire_diagram.html

Image courtesy of chinese-parts-canada.com.

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: 

http://www.sportdevices.com/ignition/ignition.htm
http://www.sportdevices.com/rpm_readings/index.htm

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.

Overview.

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. 

Wiring Our Own Power Extension Cord

One of the major challenge on our FYP is the restriction to get our project bike into our room; we tried to appeal, but refused. The refusal costs much of our time.

Hence, the need of long power extender. We need it to probe signals on the bike with oscilloscope.

On 30th Jan 2013, Sudirman, with the aid of Fazrol, managed to get it done.

Snapshot of the scene.

Many thanks to Fazrol for helping us... :)

Better PCB Etching Solution?

So, after being tempted by various sites, I finally can't help to try it for myself; particularly this one.

Yesterday, 29th Jan 2013, Sudirman and I go to local pharmacy and hardware shop to get our hydrogen peroxide and hydrochloric acid (muriatic acid).

We bought two H2O2, to make sure everything works well.

Does it works better than ferric chloride? I don't know, no experiment being done yet, maybe near in the future. :)

Getting Project Resources

On 26th Jan 2013, we managed to allocate some time to get our resource, at the famous Pudu Pasar Road

On our way home.

Reviewing bought item.

We spend close to MYR200 on that day, buying E24 resistors, LCDs, PIC-MCUs, SLA-batt, switches, flux, caps, ultrasonic transducer, PIR sensor, and Haidar's Transformer.

Spark Plug Side Gapping Mod

On 14th Nov 2012, Sudirman and I attempted to try the famous spark plug mod, mostly inspired by this webpage, on our project bike.

Sudirman disassembling front fairing.

Complete removal of ground electrode.

The result is quite surprising. Improved performance, easier starting, better low-end torque and the most obvious. smoother idling.

Video might follow... To be continued. :)

Update: On 24th Jan 2013, we tried to improve our test procedure.

Initial state.

Making progress...

Getting closer.

Finally.

Before modded.

Being modded.

Comparison between plugs. Notice there's more exposed spark area.

Installing and ready for test run.

Result: Somehow, after numerous test done, it's confirmed, that our previous result was a placebo. The engine suffers at both low and high-end curve. Main suspect is the increased spark gap distance. Need to redo this experiment.

Update:  In 25th Jan 2013, being unsatisfied with previous result, we decided to make a better test rig, this time, with proper test procedure than before.

Three spark plugs and a feeler gauge on a Dremel like tool case.

Stock spark gap was about 0.5mm.

Using cutting tool to trim the ground electrode.

Result: Sadly, the test needs to be postponed, due to insufficient time and resources... Video still unedited. 

Just Can't Get Enough PSU

Somehow, someday, you'll mixed up your designed circuit with both CMOS and TTL, once this point reached, you wondered; "seriously, who says you could get enough PSU to play with?". :)

Anyway, here's my version of solving my problem quick.

Nothing special really, it's just a family of 78XX-series linear regulator, with 12V, 9V, and 5V output, starting from yellow to black (ground) respectively. Heatsink was from old ATX PSU.

Input coming from 16V power-adapter, via barrel-jack, filtered by 6800uF cap.

In my academic years, most of the colleges used to discard stripboards, so I take it. 

Using it as the main base; not pretty I know, but hey, when you're cheap and desperate enough, anything could work. :)

3W Homemade Flash Light

At some times, I just need a bright flash light, that doesn't costs too much.

Yup, I'm using discarded Li-Ion batteries. 

No lens attached yet.

Front view. Note the heatsink.

Switching mechanism is just a simple wire header.

Close-up.

Operating.

3W is bright enough for now.