A DIY air quality monitor built on an ESP32 and a modern particle sensor is one of the best home automation projects you can finish in a single afternoon. Wire a PMS5003 or the newer Sensirion SEN66 to an ESP32 and flash ESPHome . Within minutes, Home Assistant finds the device on your local network. No cloud account, no monthly fee, no privacy worries.

Why Monitor Air Quality at Home?

Most people think of air pollution as an outdoor problem. In fact, indoor air is often worse. Cooking on a gas stove, burning candles, running a laser printer, using sprays, or even new furniture off-gassing formaldehyde can push indoor pollutants well above outdoor levels for hours.

The average American household spends about $1,500 a year on electricity. Most of it walks out the door with no clear sense of where. Your utility’s smart meter reports yesterday’s total. It won’t tell you that an old game console pulls 30W while it sits “off,” or that your water heater runs right when grid prices peak. Home Assistant fixes that. Pair the right hardware with the built-in Energy Dashboard, and you get per-device, per-circuit visibility.

A DIY smart mirror uses a two-way mirror panel, a monitor, and a Raspberry Pi running MagicMirror² . Behind the glass, the monitor shows widgets that seem to float in the reflection. Link it to Home Assistant and it turns from a novelty into a useful home panel. You see which lights are on, if the front door is locked, and your next calendar event.

Materials and Hardware Shopping List

Getting the parts right before you cut or mount saves a lot of pain. Two pieces shape the final build: the mirror and the monitor.