vion-sensor

A security sensor on an ESP32-CAM board. It notices people moving in a room by how they change the Wi-Fi signal between the board and the router (Wi-Fi Sensing): no video, works in the dark and through a door. The camera of the board is optional.

Setting up a board

1. Flash the VION Sensor firmware once over USB (see sensor esp VION in the VION project).
2. Power the board where it should watch. It shows its own Wi-Fi network VION-Sensor-XXXX: connect a phone to it,

choose your home network (2.4 GHz) and enter its password.

1. In VION open Sensors, Found, and add VION Sensor XXXX. The board gives this VION its key: from now on it

answers only here.

1. For 30 seconds after the start the sensor learns the empty room: keep the room empty.

If the board does not appear, type its address in the settings of this plugin.

Settings of a sensor

• Sensitivity threshold — how many times the signal has to change more than in an empty room. Lower is more

sensitive and gives more false alarms; start at 1.4.

• Motion lasts, seconds — how long the sensor stays in motion after the last movement.
• Camera — turns the camera of the board on; it then appears in Cameras, Found. The board restarts and

calibrates again.

• Calibrate — learn the empty room again (leave the room first).
• Update the firmware — appears when a new firmware is out; the board downloads and checks it itself.
• Reset the sensor — the board forgets the Wi-Fi and this VION.

Three quick power-ons in a row (each shorter than 10 seconds) also reset the board.

Presence and the radar (firmware 1.1.0)

• Presence — the second sensor of a board, offered in Sensors, Found once its motion sensor is added. It

notices a person standing still too (the Espressif esp-radar algorithm) and learns the empty room in the same 30 s as the calibration. When the Wi-Fi signal is too uneven it does not learn, and presence stays unknown until the next calibration; motion works as before.

• Motion from — which algorithm makes motion in VION: VION's own, Espressif's or either. Both run all the time.
• HLK-LD2450 radar (optional): wired to the board (TX of the radar to GPIO13, RX to GPIO14, 5 V and GND), it gives

the positions of up to three people to the floor plan.

• A firmware that does not start takes the board back to the previous one by itself; the settings say so.

Boards with the ESPectre firmware

A board can run ESPectre (by Francesco Pace, free software under GPLv3) instead of the VION Sensor firmware: its official release, as is. ESPectre finds motion with a statistical detector or with a small neural network trained by its authors. This plugin only talks to the board over the network.

1. Flash the official Native firmware for the chip of the board over USB at

espectre.dev/tools/flash (desktop Chrome) and set the Wi-Fi there: the board has no Wi-Fi network of its own.

1. In VION open Sensors, Found and add the board (maker ESPectre). It is found by mDNS; if not, type its address

in the settings of this plugin.

1. The settings of the sensor: Detection (Lightweight, or High accuracy — the neural network, no calibration),

Motion threshold (a probability, 0–1), Readings to start motion and to end motion, Signal source, Calibrate, and the firmware update from the ESPectre releases. Motion lasts, seconds (8 unless set) is kept by VION: how long the sensor stays in motion after the board's last reading of it.

The ESPectre API has no password: any device in the home network can change these settings. ESPectre sees motion only: it does not tell a person from a pet, count people or prove that a room is empty.

Placing it

The sensor sees best what moves near the line between the board and the router. Fix the 2.4 GHz channel of the router (not "auto") and a 20 MHz width: a changing channel looks like movement.