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 input
On 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..
Fitting Pico’s where they probably shouldnt be
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