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What 24 GHz mmWave Radar Sees Through the Wall
A presence radar reports a distance and an angle. Whether those coordinates are inside the room is not something it can know – and plasterboard does nothing to help it find out.
Smart Home
18 articles in this category
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A smart home should be useful in everyday life. For that to happen, sensors, wireless networks and automations need to work together. Here I look at the technology behind them and explain how the parts connect.
You will find posts on Home Assistant, Zigbee, Z-Wave, Matter, Thread and MQTT, along with energy and solar topics. I also cover local control and home network integration. The examples help you think through automations for your own home.
Tutorial: Reading SunSpec Registers From a PV Inverter Over Modbus TCP
A register number from a forum post works until the firmware moves it. Walking the SunSpec model chain finds the same value on any inverter – and the scale factor two registers further on is what turns 1234 into 12.34 amperes.
Local Voice Control in Home Assistant with Whisper & Piper
A technical step-by-step tutorial on building a private, cloud-free local voice assistant in Home Assistant using Whisper, Piper, and the Wyoming protocol.
Tutorial: Setting Up LD2450 Radar Zones in ESPHome and Home Assistant
An LD2450 reports coordinates in millimetres, and a zone is four numbers around them. Getting those four numbers right is a matter of measuring rather than estimating – and of knowing where the sensor thinks the origin is.
Automating Solar Energy in Home Assistant: Dynamic Surplus Charging
A technical step-by-step tutorial on implementing dynamic solar surplus charging and load modulation in Home Assistant for batteries and high-demand appliances.
Tutorial: Publishing an MQTT Discovery Payload That Reaches the Energy Dashboard
One retained JSON message on the right topic creates an entity in Home Assistant. Three fields inside it decide whether that entity can also be picked as an energy source – and none of the three reports an error when it is wrong.
Sharing 2.4 GHz: What a Zigbee Channel Change Costs
Sixteen Zigbee channels sit in the same band as three Wi-Fi channels, and only four of them are clear. Picking the wrong one is free on day one and expensive on the day it gets corrected.
Home Assistant Energy Dashboard: Device Class, Unit and State Class in the Discovery Payload
Device class, unit and state class are three lines of a discovery payload, and all three have to agree before an entity can be picked as an energy source. None of them reports an error when it does not.
PV Surplus Control: Hysteresis, Timers and Thresholds for Switching Loads
Switching a load on when the surplus is large enough removes the surplus, which switches the load off, which brings it back. Two thresholds and three timers turn thirty-seven switching operations into two.
WireGuard & Tailscale DMZ: Secure External Access to Home Assistant and Self-Hosted Servers
Why eliminating public port forwarding (80/443) and NAT exposure in favor of encrypted point-to-point WireGuard or Tailscale VPN tunnels is essential for modern home server security.
