There is a similar thread at What did you build/automated today (with pictures)?
Temp/Humidity/Light sensors
Based on NodeMCU ESP8266 microcontrollers running ESPEasy. They have DHT22 and simple light dependent resistors (these require being connected to the analog pin). They report to MQTT periodically where OH gets the readings. I use mains power to run them, not batteries. I’ve built three of these.
The case is repurposed from a set of souvenir gin samples I picked up on a trip to Nova Scotia decoupaged with washi paper.
It would be much neater and probable last longer if I use a small breadboard or perf board but I didn’t have either when I made these so they are kind of free floating circuits.
This one is in a cricket box I got from a craft store. It’s in my son’s room so he got to decorate it (he did so when he was 4 or 5, I can’t remember).
This one is also in a cricket box decoupaged with washi paper.
Garage doors
My first DIY home automation project and in desperate need of redoing. But it’s been running well since before I even moved to openHAB, upgraded once from an RPi 1 to an RPi 3. I have two garage door openers so there is a dual relay and two reed sensors wired up to the GPIO pins. The relays are wired to the wall buttons so when the relay turns on the opener sees it as the buttons were pressed. My sensorReporter script sends sensor readings and receives commands to open the door using MQTT.
I’ve also a raspicam plugged in to it to have a way to monitor and check on the garage door (I especially don’t want to be closing it without having eyes on the door. However I’ve now a Wyze came in the garage so this camera isn’t really being used.
I intend to replace this with a NodeMCU version in a nice case since I no longer need the camera. But that’s a lower priority project for me right now and the project cases I got is just a little too small to fit everything so I need to come up with an alternative. Now that I have a 3D printer I’ll probably design and print a case.
“Alarm” system
The previous owners of our house had an alarm system. But the system was removed prior to our buying the house but they left the sensors in place. So I got an RPi 0w and wired up to some of the sensors. I was able to get the door sensors working no problem. But the window sensors and vibration sensors probably take more than 3.3v to run. At some point I may play with it again, maybe get one of those ESP based boards that are designed to replace alarm systems like these and try to get the other sensors running. This one is also running sensorReporter.