Work-in-progress. Please use at your own risk.
This is a board intended to function as a "magnetic field camera", and visualize magnetic fields.
The major advancement of v3.0 is a dramatic increase in the speed with which the tile data can be read out. I have achieved ~2000 frames per second (fps), which allows visualizing even quickly varying fields (e.g. those in a 60Hz transformer, or a moving motor), but it's likely that the tile can achieve even higher framerates. Version 3.0 reduces the size of the tile to an 8x8 grid of hall effect sensors (64 total), arrayed in a 4mm grid. The boards should also still be tile-able, with up to 4 of the boards tileable with minimal borders to create a 16x16 array.
For more information (and a video of the v3.0 tile in use), please see: https://hackaday.io/project/18518-iteration-8/log/91551-a-third-high-speed-magnetic-imager-tile-draft
Version 2.0 consists of an array of 12x12 hall effect sensors (144 total) that sense magnetic fields, arrayed in a 4mm grid. Each sensor is connected to an array of analog switches, that allow an individual sensor to be addressed. Read out is accomplished one magnetic "pixel" at a time, selecting a given hall sensor from the array, reading it's value (either using the internal ADC, or an external ADC), and repeating this process until the entire array has been read out.
The current array is designed to be tile-able, with up to four of the boards (24x24 magnetic field sensors) arrayed together.
The Arduino firmware has a framerate of approximately 10 frames per second, when the image data is streamed over the serial port and displayed using the Processing visualization. The Raspberry Pi Python example achieves approximately 30fps. The array itself is likely capable of much higher speeds, but one of the major limiting factors is currently the speed of the I2C I/O multiplexer (used to select which magnetometer to read from).
For more information (and a video of the v2.0 tile in use), please see: https://hackaday.io/project/18518-iteration-8/log/64376-a-magnetic-imager-tile
This project is open source software and hardware, and is released under various open licenses.
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