My main tools of choice are ESP32 and ESP8266 modules. I'm generating Home Assistant compatible firmware for them with ESPHome.
I have also few Shelly products controlling 230 V lights. I use
Raspberry Pi for hosting the Home Assistant server
Tailscale add-on for remote access
LD2410 24 GHz millimeter wave radar for motion and presence sensing
BME280 for measuring temperature, pressure and humidity
TEMT6000 ambient light sensor
SenseAir S8 CO₂ sensor
WiZ tunable white smart bulbs with WiFi
I created a minimalist user interface based on Home Buttons. It displays electricity market price on the top and outside temperature on the bottom. The buttons are all programmed with different lighting scenes.
The code snippet above shows custom RESTful sensors for fetching electricity price data from Elering and atmospheric conditions data from Ilmateenistus.