An ESP32 ESPHome device in the furnace room reads a differential-pressure sensor across the filter and watches the furnace control board’s status LED. Home Assistant turns the raw pressure into blower speed, filter loading, and a replace-filter alert. The threshold comes from a real clean-filter-vs-old-filter experiment, not a guessed limit.

A stock Zigbee door/window sensor, with its Hall-effect chip desoldered and two wires brought out in its place, becomes a cheap, battery-powered interface for any simple contact: reed, pressure pad, or float switch. Built to stop Home Assistant from switching off the office lights while sitting still at the desk; the same trick already covers a toilet tank float and a Christmas tree water level.

A 3D-printed clip mounts a submersible float switch on a toilet tank’s overflow tube and wires it into the same desoldered-Hall-effect Zigbee mod used for the office chair sensor. The result: Home Assistant catches a stuck fill valve before it turns into a running toilet, and gets a flush count for free.

Wiegand data lines idle at 5V, and the ESP32 is not 5V-tolerant. You don’t need a level-shifter IC or a resistor divider. A single signal diode does the job, and it does it better.

A look inside a fully local, cloud-free Home Assistant installation: 1,900 entities, 66 automations, 20 rooms, and a Raspberry Pi 4 running the whole house.

Printed holder mounts the Aqara Motion Sensor P1 to standard US 1" × ¼" peg board. Quick to reposition wherever peg board is present.

Blocks internet access per-device on a schedule using OpenWRT nftables rules, with a Home Assistant dashboard toggle for manual overrides. No third-party apps or cloud dependency.

ESPHome config for a Wiegand keypad reader built on a thin-edge philosophy: the device only captures input and relays it to Home Assistant. Now folded directly into the garage’s RATGDO board instead of running on its own standalone ESP32.

Wall-mounted friction-fit holder for the Bond Bridge BD1000 RF blaster. Quick mount and unmount to a wall panel for home automation use.

Slim snap-fit case for the Wemos D1 Mini ESP8266. Optionally adds external LED holes and a 6.5mm clip for mounting to a laptop display. Pairs with ESPHome and Home Assistant as a simple status indicator.

Two ESPHome configs for a SONOFF S31 smart plug that auto power-cycles a device when it stops responding. One using ICMP ping loss detection, one using Home Assistant API connection loss.

Clip-on holder turns an Aqara Water Leak Sensor into a Christmas tree bowl water level monitor. No more dry trees.