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wifi_camera

A camera that can see WiFi signals. Just the sensor unit. Currently planned for 8x8=64 pixels.

result of a scanned 3D frame

3D capture of a wifi signal in a 20x20x20 cm grid.

What it does

The sensor array captures RSSI values from near by WiFi networks and sends the collected pixel data to a master that processes and visualizes the captured data. The goal is to build a sensor, that makes WiFi signal visible in more or less real time.

Why?

WiFi signals are invisible to humans. I think it would be fun to make them visible and play around with it. Projects I have in mind unsing the sensor array: real time analysis of antennas and obstacles..., real time object/person detection/tracking by reading WiFi shadows and reflections, using the standing wave to 'surf' it to get position data back for i.e. robots.

4x4 pixel array

How?

Before this, I built a rig to scan and visualize WiFi signal propagation in 3D

https://hackaday.com/2021/11/22/visualizing-wifi-with-a-converted-3d-printer/

https://github.com/Neumi/3D_wifi_scanner

This got me interested in building a real time, sensor array to take a whole frame at once without having to scan a slice one position after another.

To capture a whole slice at once, I built this array unsing four PCBs with 4x4 ESP8266 sensor nodes connected via i2c where every pixel is an i2c slave and a master that asks the pixels one by one for the captured values.

four 4x4 pixel arrays

I'm currently waiting fore more ESP8266s to arrive.

Results

The results look pretty granular currently, as I only used 4x4 pixels, which is a bit low. When more ESPs arrive, I will take more images. 16 pixels 16 Pixels, x-axis is time, Y axis is RSSI with an offset between each pixel for visibility. four 4x4 pixel arrays 16 Pixels with correct orientation in a 2D plot.

Video of 4x4 test grid:

VIDEO

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A camera that can see WiFi signals.

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