Accurate fluid level sensor

Uses a float to rotate a pin holding a small 5mm magnet. magnet angle detected by a low cost GY-273 compass module, liquid depth calculated based on length of float arm and angle.

Float arm I used 4mm oak dowel. Float halves filled with high density foam the superglued together, then I coated my float with a varnish for added waterproofing.
Magnet is held in 5mm hole in hine_pin part with hot melt glue,
GY-273 fits into pcb_holder then also sealed in place with glue.

Accuracy with a 300mm arm seems better than 1mm, certainly very repeatable.with low noise.

Code is a modified example of the adafruit sensor library which adds

Added some screengrabs after adding a few parts for clarity. the 2 blue parts are glued together with the pivot in between and there are a couple of 2mm holes to add some printer filament into as a dowel and guide.

the silver part is the magnet and shows the hole it goes into and orientation, the black part is the edge of the tub that the bracket