2016-10-18

Turn on/off any PC with an ATX PSU and InfraRed remote

My HTPC has/had a CIR which allowed me to turn it on via my Harmony remote, but one day it stopped working and my attempts to fix it totally broke it.
So my 1st idea was I'll buy a new CIR device, but I couldn't find any.
My 2nd idea was get a new Motherboard, but that meant new CPU (Skylake i7-6700k) + RAM (DDR4) bcos there's no point getting a new Mobo if your not getting the latest and greatest, and I couldn't find any which turned on via IR.
My 3rd idea was build something :), this turned out to be ridiculously easy.

What would I need? Some way of automating pressing the button for 2 seconds, bcos that turns the PC on and off, and something to accept an IR signal.
I knew ATX PSU's have a 5v standby power supply, so IR relay would need to operate on 5v.

A quick google didn't help, so I went to Alibaba and found exactly what I was looking for, a 5v IR relay with timer function. I then went to eBay bcos I prefer the buying experience. Programmable Timer Relay Module + IR Remote Controller for $5 how awesome is that!?
3 weeks later it arrives and I proceed to install it. 


Please excuse the poor drawing, I don't have Visio installed on this PC.

Steps:
  1. Test relay to ensure it works.
  2. Program your universal IR remote unless you want to use the included one. My Harmony Elite had a really hard time learning the IR command, and even when it did it wouldn't work the 1st time, but it eventually learnt the command.
  3. Set relay time to 2 seconds, shorter will turn it on, but may not turn it off. 4 seconds will force a power cut.
  4. If required extend the infrared phototransistor, black shiny thing with 3 pins. I extended mine by 30cm to have it sit outside the case.
  5. Either find 5v on a motherboard pin header (there's bound to be a couple) or get it directly from the ATX connector.
  6. 5v in to the IR relay power input.
  7. Run 2 wires from relay output NO + COM to the Power Switch pins on your motherboard.
  8. T join the case front panel power switch to the Power Switch pins on your motherboard so you can still use the normal power switch.
  9. Test. Apart from the Harmony learning command issue, it has worked flawlessly for the past 2 weeks and I like that it turns off instead of the Alt+F4 I used to do. I even use an Amazon Echo + Harmony + Yonomi to voice control it with; Alexa, turn PC on/off.
Relay with extended phototransistor

T/Y join of front panel I/O + Relay NC/COM

The relay on top of the PSU in the case