Through-wall presence sensor from Wi-Fi noise

An ESP32 can read Wi-Fi channel state information, and a person walking through a room disturbs it. Turn that disturbance into a presence signal a home automation system can use.

Requirements

Read CSI (or RSSI as a fallback) from an ESP32 at 10 Hz or better

Compute a rolling variance and expose a boolean "presence" with hysteresis so it does not flicker

Publish presence over MQTT with a Home Assistant discovery payload, so it appears as a binary sensor with no manual config

A calibration command that samples an empty room for 30 seconds and sets the threshold

Work on a real ESP32 or in the Wokwi simulator with a replayed CSI capture (one is provided in the repo)

Technical Notes

ESP-IDF or Arduino core, your choice. The replayed capture lets the whole task be done without a board.

Bonus Points

Distinguish "someone walked past" from "someone is sitting still"

A tiny web page on the device showing the live variance

esp32iotmqtthome-assistantsignal-processing

Free stage

SeniorFree

Starter repo

You connect the GoShip MCP server to Claude Code or Cursor. It records your prompts, tool calls and test runs, and that record is what gets scored.

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