Sunday, January 1, 2012

Making Solid State Switching for Car Headlights

Commonly, car headlights are triggered with relays. I'm fine with that, but, I just dislike the way the contacts wears out over time.
Solid State Relay (SSR) are already in the market, but tend to be quite pricey.

This is my attempt of building one cheaper.

Preparing the PCB.

Searching for perfect configuration.  

Cleaning the heatsinks.

Applying thermal paste, using line-method. Why?

Ready to go.

Upper left is the 555 inverting gate driver, lower right is the power PMOS.

Almost done...

Cleaning flux residue with methanol.

I'll update this post soon.To be continue...

Helping Halim

My pal Halim want to weld his table. So, me as his good friend, just help by standing, watching him. :)

He's busy, I'm not... :)

Work in progress...

So, yeah, the table is usable now, but, with great deal of worries... :)

Reviving Old Speaker Amp

About five years ago, I'm using my PC as signal generator, and this speaker amp to drive a transistor, which is then driving an ignition coil. I'm using only the left-channel at that time.

While having fun, for maybe about 3 months, boring with just 12V supply, I tried 24V. It ran for few minutes, then, ..., silence... I blew my amp! Feeling guilty, I decided to stop play with it for a while.

Listening music with only my right ear for quite some time, I decided to play with it again.
And yes, now the both of the channels are burnt!

With some few limited spare time, I try to revive it back.

Long time no see...

Opening the back cover.

Here's the circuit board.

Close-up on blown amp IC.

New TDA2030A. :)

Unscrew the heatsink.



Poor IC.

Unscrewing them.

End up in my junk bin.

Old thermal paste, need to be clean...

Using methanol.

Wiping it off.

Applying fresh paste.

Kids, don't do the same mistake as I do here.
Don't fasten the screw with powered screw driver!

Now, that's better.

Soldering it back.

Reconnect any connectors left.

Reinstall the back plate.

Hey, it's alive!

Me and my dad bought those IC for about  MYR3 each. New speaker amplifier costs almost MYR100. That's a huge saving!



Bench PSU

In previous post, I said I want to build an opamp circuit to amplify the TPS signal by x3. The TPS requires 5V to be applied. Rather than just take a common LM7805, I thought, I prefer to have an adjustable PSU.

So, here we go!

I'm too lazy to make my own PCB, so, a basic kit would be nice.

The subjected case.

Cutting perfboard for the pass-transistor.

Drilling hole for heatsink.

Hole for the pot.

Almost done...

It runs!

View from above.

Backside of it.

Powering a load.

Yeah, I know I've done a blog post before on modding PC PSU as bench PSU, but, I don't really like the metal nature of the housing. 

Keep busy! 

Homemade TPS Sensor

Throttle Position Sensor (TPS) could be quite expensive, so, why not DIY It? :)

The stock TPS worn out due to ageing issue, so I'm keen to mod it.
In my case, I just use a 10kR pot, then, atteched it directly to the stock TPS.

Resurrected... :)

Another angle.

Yet another angle...

Testing on O'scope...

The throttle rotate fully to about 90 degrees, the pot is about 270 degrees. Hmm...
According to the o'scope, the output is about the third of the input.
So, I need to add some sort of an amplifier to it, I'm planning to use an opamp with the gain of x3.

To be continue...  

Fume Extractor

Hey, long time no see! Lol! Yeah, I've been busy lately, living my life, as a human. Anyway, let's see whaatssuup!

So, apparently, I need some sort of a simple fume extractor for my everyday soldering task, buying one would break a bank, so, I DIY'd it.

This is a common car air filter, with AC fan on it.




The subjected fan.

Eyeball'd for center, then glue it.

Seal any visible leaks. Oops, I just noticed the flow direction is wrong. Lol!

Make sure the air flow is right. :)

View from an angle, no visible leak.

Same here...

Hey, it works! :D

Unfortunately, it failed to do its task of extracting fume. The filter clogged bad enough to render it useless. Sigh...  

BTW, Happy New Year!