# lab note

Weekend Lab Build: an ESP32 air-quality node in an afternoon

From breadboard to Grafana in a few hours — MQTT, Home Assistant, and a clean repo.

June 8, 20261 min readWeekend Lab Builds

Sean · wrote this at the bench

iotesp32mqtt

A small sensor, a cheap ESP32, and MQTT into Home Assistant. The goal: real numbers on the wall by dinner, with a repo anyone can reflash.

The problem

A small, annoying task that was eating time and attention every week. We measured it before touching anything.

One focused change, reproducible, with a guardrail and an obvious way to turn it off. No magic, no vibes.

$ ./run --dry-run
[ ok ] plan looks sane
$ ./run --apply

Before/after benchmarks, the failure modes we hit, and the tradeoffs we accepted. The repo has the full runbook.

$ subscribe --email

Automation patterns and lab updates. No hype, no spam.