Infra Red i/o Control over Desktop PC via MOSFET Transistor

Hi,

please forgive me ignorance, but I am having a problem with an infra red control I am building to turn on my pc (from shut down, not to wake it up from suspend mode). My idea is to use a simple 9v infra red transmitter and a phototransistor, which activates the gate on a transistor, which in turn completes the i/o circuit for the pc button and turns it on. The switch works perfectly when I connect it to my circuit tester, but when I wire up the i/o button for the pc to my receiver, the pc turns off because the i/o button circuit is constantly made. I can provide a really basic schematic if it helps, but if anyone has tried this before or has any idea why this is not working I would be much obliged.

many thanks,
Chad

A simple photo transistor will respond to all light. You need a IR demodulator like a TSOP1138, BUT that will still respond to spurious IR noise so you'll need something like a microcontroller to decode an IR data stream like the type your remote puts out.

Thanks for your very quick response Bill. Your reply makes a lot of sense, but I fear I am too inexperienced to embark on a project like that. Do you know of a single solution I could buy to create the same effect? The only infra red controllers I have seen for PCs only wake them from suspend mode, which is no good for me! Alternatively, do you know where I could get a schemtaic for the type of solution you outlined above?

If room light is a problem, there are filters available that block most room light but let through the IR. That might solve your problem.

Here's a link to a small IR device
http://www.sixca.com/eng/articles/remote/index.html