Power up your computer wirelessly with Wemos D1 mini

Tired of reaching for that power button? Or perhaps you’d like to be able to turn on your PC when travelling? I sometimes like to do that to access some local files (or software via VNC), but dislike leaving the PC on for days “just in case”. This article explains how you can do it with the $3.50 Wemos D1 mini.

Wake-on-LAN is of course a great idea, but it only works if your PC is physically wired to the router. Wake-on-WLAN theoretically should work for WLAN as well, but here’s a shocking revelation: it usually does not, as it requires your PC to power up your WLAN card for it to receive the magic WLAN packet, and router support. At least I’ve never had a combination of network card and router that would work.

I used to have a nice DIY knock-sensor to PS/2 thingy, but the piezo kept dropping out, and got tired of repeating the required sequence of knocks. So I thought it would be cooler to have just a Bluetooth button I could use to do the same. I had a WLAN enabled Wemos D1 mini board lying around, and it only draws less than 100 mA of power, so I thought to find out if I could make it listen to a “magic packet” and boot up my PC. Turns out it was easier than I even thought!

Note that this project involves opening your PC case and playing around with your motherboard power switch wiring. Everything should be relatively hard to screw up, but if done wrong, you may get electrocuted, you may stick a screwdriver where it shouldn’t go and damage your motherboard or other components, so proceed with your own risk!
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IR signal recorder with Arduino Uno

I’ve been tinkering with IR and the TSOP38238 IR receiver modules I got from Adafruit and Sparkfun. That’s right, plural, as I burned the first one — be REALLY sure not to mix ground and VCC with this one! I ordered 10 more from AliExpress just to make sure I have spares in case I burn my second one as well…

There are IR libraries for Arduino already, but they were a bit complex to my taste, as I’m first planning just to record one IR code from my bulky Sony projector remote and make a small trinket to send that on button press. The TSOP382 already demodulates the signal, so I just want to record the times the remote IR led is on, off, on, off, and so on. So I made an Arduino sketch to do just that: Count loop cycles, detect when signal goes from high (no IR signal detected) to low and vice versa:
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