When the First Alert Fails: Building an Escalation Chain for a Water-Leak Notification
A water leak is a condition, not an event. That distinction is the whole problem with the way most of us wire up leak notifications. We write an automation that triggers when the leak sensor goes on, sends a notification,…
Unplug One Mains-Powered Bulb and Six Sensors Go Quiet: Watching a Zigbee Mesh Re-Route in Real Time
You unplug a lamp to move a chair. Within a few minutes, a door sensor, two motion sensors, and a temperature sensor stop reporting. The lamp is not on any automation that matters. The sensors are. This is the ordinary…
Designing a Housesitter Mode: Paused Automations, Temporary Access, and Controls a Stranger Can Operate
Housesitter Mode is not a feature you install. It is a small set of Home Assistant helpers that give a visitor one switch to flip, one bounded number to adjust, and one lock button to press — while the automations…
Replacing a Zigbee Coordinator Without Re-Pairing Forty Devices: A Pre-Flight Decision Procedure
The phrase “network-key migration” is the wrong mental model for a coordinator swap, and it leads people to look for a step that does not exist in the documented workflow. The network key is not the thing you carry across…
The Sensor That Failed Silently: MQTT Last-Will Messages and Detecting Devices by Their Absence
A sensor stops publishing. Nothing in the dashboard changes. The last value sits there, looking like a reading, and the only thing that has actually happened is that no new message arrived. Silence is not an event unless something is…
What Each Smart Plug Does When the Power Comes Back: Configuring Restore States So an Outage Doesn’t Switch Everything On
After an outage, the question everyone asks is “what does my smart plug do when power returns?” The honest answer is that you cannot answer it from Home Assistant’s side. Home Assistant only observes the resulting state. The restore behavior…
Why the Garage Sensor Dies Every January: Cold-Weather Battery Sag and What the Voltage Log Shows
The garage door sensor goes unavailable every January. You replace the battery, it works again, and you file it under “winter is hard on batteries.” That story is plausible, but it is not a diagnosis. The sensor might be sagging…
Buying a Used Smart Lock: What a Factory Reset Doesn’t Clear and How to Verify You Actually Own It
A factory reset on a smart lock is not a title transfer. It usually clears the local keypad codes and may drop the lock from the previous owner’s app, but it does not reliably remove the lock from a vendor…
Home Assistant Slows Down After Six Months: Recorder Retention, Database Bloat, and a Purge You Can Measure
The “six months” story is folk wisdom, not a documented mechanism. Home Assistant’s recorder documentation describes continuous recording and default purge/repack behavior, but it does not claim that a specific elapsed time causes slowdown. What the docs do support is…
Knowing the Sump Pump Is Failing Before the Floor Does: Cycle Counts, Runtime Trends, and a Float-Switch Alarm
A sump pump fails in two directions. It can stop running when water is present, or it can run when water is not present. The first failure floods the floor. The second failure burns the motor and often precedes the…