Sunday, July 3, 2011

Quick Project: IR remote-control power strip

I wanted a remote controllable power strip for my modest media-player setup consisting of small PC multimedia speakers, a chinese SD media player like this
and a USB HDD enclosure. I wanted the ability to conveniently power them off together for a couple of reasons: The speaker's amplifier produces an annoying hiss, and the media player's power LED is on constantly despite the player being off and is super bright, and I'd want to switch the HDD off anyway.
I know I could've just went out and bought an RF thing for around 10EUR but where's the fun in that?
Also this way I didn't add to the number of remotes I have. (I'll explain below.)
Salvaged a SOIC ATTiny26 from a busted coffee maker earlier. Soldered wires to it's pads so I could use it on simple experimenter's board. It also looks funky enough.



On the left is a standard ISP header.

I had an SFH506 IR receiver/demodulator which was already discontinued back in the days when IR remote control was all the rage in hobby projects here. The suggested replacement units never seemed to last that long. Maybe they were rated for a 3.3v, didn't bother to check then. Anyways this was the real thing, salvaged from an old VCR.


I had a generic 5V relay from a busted old CRT monitor which I'm switching from a GPIO of the ATTiny through a generic transistor. Power this all from an old cell phone charger board.
That's basically the setup. Ghettoed it all together in an acrylic box using zipties, hot glue, heat shrink and double sided mounting foam tape. (It does say quick in the title.)


Besides the initial soldering wires to the pins of the SOIC chip operation the entire thing probably didn't take 30 minutes to finish (including coding time) and it's been working great ever since. As for the remote:
I use a universal remote from my TV that has a slide switch for switching between TV and VCR modes. I decided to make use of that since I don't need the VCR functionality on it. It works out great because I can just set up an RC5 VCR code on the thing and RC5 is extremely easy to handle in BASCOM (basically just 1 function in a loop.. GetRC5).

All in all it was a fun project that I now use all the time, hardly took any effort to finish and was basically made from parts from the junk box.

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