I made a simple HAT (Hardware Attached on Top) for the Raspberry Pi to read multiple DS18B20 temperature sensors — it was surprisingly easy. I used the measured temperatures to control a fan using Home Assistant.
A kids alarm module, with buttons and lights. Powered by a Raspberry Pi Zero, connected to WiFi and MQTT.
Making a single relay controlled with WiFi MQTT from Home Assistant, using WeMos D1 mini board.