Microcontrollers
I’m not much into electronics. But I’ve been playing around with some Pi Pico recently. These are some of the projects I’ve cobbled together.
Hifi Volume Control
Version 2 is currently in regular use, and has been working without issues or need of intervention for the last few months. A Pi Pico (sitting on a breadboard) is hooked up to a small 5v-accepting stepper motor and an infrared receiver. Around the motor goes an elastic belt with enough grip to rotate the volume knob of my Hifi.
Version 1 utilised a single mesh book-end, with holes cut to allow the motor shaft to pass through, and to allow for mounting with cable ties. While it did work, it required a large weight to be placed on top of the base of the book-end to prevent the elastic belt shifting the entire unit.
Version 2 made a sensible (and linear) improvement, utilising two solid book-ends glued together to form a half-cube. The book-end on the bottom extends underneath the Hifi, and is held down by the weight of the Hifi itself. This stabilises the entire unit, and keeps it neat without needing to mount the unit to the Hifi in a permanent way.
Version 3 is planned, and will probably make use of an aluminium project box, NEMA 17 motor, and USB-C for power. There are a few things I'd like to add:
- A few buttons and a blaster, to allow programming Apple TV remotes with fixed codes for volume. Right now, I'm using an old Bush-branded remote for training both. If I lose it, that'll be a problem.
- Mute functionality. It can't be instant, given the motor needs to rotate. But remembering position would be useful.
- Housing the board inside a black metal project box, with a NEMA 17 motor mounted on top with an L-bracket. This would look nicer than the bookends and tidy things up.
- Dig out some perfboard and mount things properly. Right now everything is hooked up on a breadboard with jumper-jerky.
- 12v USB-C power input.
- A proper drive belt. Probably PU, or something with teeth.
Conservatory Wifi Temperature/Humidity Sensor
A Pi Pico with a little wifi board and a BME688 sensor. Readings are fetched every few minutes and added to a CSV file, after which the information is plotted using GNUPlot. This was eventually rewrote for the Pico W, and plopped on a perma-proto board.
These have since between replaced with matter/homekit tat.
Pico Radio
A Pi Pico in a small metal box, utilising a Si4703 FM receiver breakout and 3xAAA batteries. I intend to revisit the project at some point, and add things that actually make use of the Pi Pico. For now it’s just an overly powerful single-station pocket radio with mediocre battery life.
If I could find where I put it, I'd have a picture. But it really is just a small metal box with a headphone jack and massive toggle switch.
Chicken Coop Door Opener
A pico-lipo, hooked up to an ambient light sensor (LTR-559), a LiPo battery, a micro-gear motor (298:1), and some fishing line going around pulleys that lift a chicken coop door when the sun comes up, and drops it again when the sun goes down. Currently written in C, owing to the lack of deep-sleep capability in micropython.
Eventually replaced alongside with the coop it was used with.