Guides

Before the sensors and the clever routines, make a plan for a home that’s dependable, understandable, and yours to control.

A contact sensor is the simplest device in a smart home, and it is still the one people most often mount wrong. Two pieces go on a door or window: a body with the electronics and a battery, and a smaller part with a magnet. When they are close, the sensor reports "closed". When the magnet moves away, it reports "open". Most problems come from those

A laser particulate sensor is one of the most satisfying parts you can wire to an ESP board. Ten minutes after powering it up you have a live PM2.5 graph, and the first time you fry onions or light a candle you watch it jump. The hard part is not getting a number. It is knowing what the number means, how far to trust it and how long the sensor will

You open the wall switch box to fit a smart relay and find two wires: the incoming live and the switched live that runs up to the lamp. No blue neutral. That is normal in many older installations, because a plain switch never needed one. A smart device does, or at least it needs some way to stay powered while the light is off.

Turning something on and off is the first real job most people give an ESP32. A blue relay board costs little, the code is one digitalWrite(), and the lamp clicks on. Then the relay clicks every time the board reboots, the module will not switch off from a 3.3 V pin, or a small LED bulb keeps glowing behind a solid-state relay that is supposedly of

Plenty of heat pump spec sheets carry a small "SG Ready" logo. It sounds like a smart grid protocol, and people expect an app, a cloud service or at least a network port behind it. What you actually get is two terminals on the controller board. You close or open them with a relay, and the heat pump changes the way it runs.

Most smart lock problems start at the door, not in the app. A lock that does not fit the cylinder, cannot be opened from outside while a key sits in the inside, or needs a hub you do not own will annoy you every day, whatever its feature list says. The checks below go in the order that saves money: the door first, then the radio, then the way you w

Buy an Apple TV, a Nest Hub and a SmartThings hub, and you probably own three Thread border routers. There is a good chance you also have three separate Thread networks. Each one carries only the devices that were added through its own ecosystem, and a mains-powered plug in one network will not relay traffic for a sensor in another.

When the power goes out, everything in a smart home drops at the same moment: the router, the switch, the machine running your home automation software, the Zigbee or Thread coordinator plugged into it, and the NAS holding its backups. Short outages then turn into long ones, because devices come back in random order and anything that was writing to