I’ve been spending some time building a lot of smaller projects around some niche parts and wanted to share a few tips and interesting techniques.
The heart of these project is the Raspberry Pi Pico.
Emulating a button press
This trusty little IC(The SN74HC4066N) in simple terms is a logic level relay - It cant switch too much voltage or current, but is more than capable of toggling IO on parts that you would find around the house.
Reading an inputOn a comsumer part there are often usable outputs, an LED is very common (and rests at a nice voltage usually) so its easy to tap into to get the state of a system. Using a [bus pirate](https://core-electronics.com.au/bus-pirate-v3-6-universal-serial-interface-seeed-studio.html) you can tap into the actual comms between chips.
I measured 2.7v on the high side of the LED, this sits above the range of the logic high threshold on the Pico.
Combining the two techniques above I was able to select the HDMI input that I wanted (using serial although this could be adapted to any other protocol) Check out the code for that here..
While stumbling around the net wasting time I came across this article about how you could cut down a Pico since the bottom porttion didnt have any sensitive components or traces that fed any signals back towards the main processor.
Check out the Tweet that inspired that post: https://twitter.com/PaintYourDragon/status/1376643550536892419?s=20
Warning, you might cut yourself or ruin some Picos if you try this!
I got a Stanley knife and made some deep cuts on the PCB on both sides and snaped the bottom part off a couple.
Now they can fit in much smaller spaces (still the same full size IO, which can be a disadvantage. For $6 this isnt too bad. If you want to spend a bit more but have a PiicoDev/Qwiic/STEMMA port check out some of the QT Py boards Adafruit make
I’ve got some other hardware hacking projects scoped up, as I complete them I’ll update this topic