wifi_camera
A camera that can see WiFi signals. Just the sensor unit. Currently planned for 8x8=64 pixels.
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.
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.
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, x-axis is time, Y axis is RSSI with an offset between each pixel for visibility.
16 Pixels with correct orientation in a 2D plot.
Video of 4x4 test grid:
