What projects have you made with boards like Raspberry Pi, Arduino?

When I was getting ready to take paternity leave I figured I'd either a) explore "hardware", or b) take a stab at learning mobile development.

In the end I started playing with Arduinos. After a very short while I got a little addicted, but switched to using ESP8266 devices - because having onboard wifi made the hardware so much more useful.

I've built, experimented with, and torn down a hell of a lot of projects in the three years since. But my absolute favourite project is nothing more than an LCD screen which shows me the next tram-departures from the local stop:

https://steve.fi/hardware/helsinki-tram-times/

That project was hacked up in an hour or two, but later made much more "producty" - being configurable with a web-browser, and being installed in a 3d-printed case I paid somebody to make for me.

Over time I've added little hacks, so now it alternates between showing "$HOUR $DATE" and "$HOUR $TEMPERATURE" in the top-line. Because my wife would often ask me "Is it cold outside?"

I've done more impressive things; such buying a random radio-based temperature/humidity sensor, then having to sniff for the packets, decode the bitstream, and inject the temp/humidity into an MQ queue. But for sheer practicality, and sheer usefulness, the always-on clock and tram display has been worth it.

My Pi 3B is a media server right now. I have it hooked up through HDMI, converted to composite, and run to my Commodore 1702 so I can watch cartoons. It has probably around 80GB of movies and another 80GB of music, 10GB of books, and a couple gigs of pictures on a partition of a hard drive that's hooked up via a SATA bay. Over the years it's been an IRC server, a Tor webserver, an emulation station, and a backup computer to watch South Park after my old one died.

Nothing very fancy:

1) A home server for hosting a couple small websites for free, instead of wasting cash on $5/mo VPS. 2) A cluster of PIs for training with distributed computing (Docker, K8s). 3) An EMP proof remote backup case with a Pi and a large, encrypted HDD -- mounted in a metal military case intended for storing ammunition. I keep it in my pal's place.

I’m currently working on a controller for my standing desk. The built-in switch was just a plain old up/down one.

I’m using a relay switch, home bridge and an infrared height sensor to automatically raise and lower the desk to certain presets.

Another project I have is to use the pi camera and a small display to detect movement and show a fact/quote/lyric on the screen.