Hall sensor testing
14 January 2020 at 8:41 am
For a personal project, I’d like to use Hall sensors to measure water level. But how do you pick a Hall Sensor when they all claim the same characteristics?
For this test, I ordered 3 different Hall Sensors in SOT-23-3 package. All 3 are omnipolar, so they will react to both North and South magnets. They all claim to have a Operation Point of 40 gauss, noted as “Bops”. The Max Bops value is a little different, but in theory, they should all trigger at the same distance. Guess what? They don’t:
|Hall Sensor Model||Trig with 8x3mm round Neodym||Trig with 60x15mm square Ferrite|
|CC6201ST||11 mm||21 mm|
|AH180-WG-7||14 mm||25 mm|
|APX8132AI-TRG||15 mm||33 mm|
I measured this quite roughly using calipers held up next to the magnets, but the deviations between the sensors are quite significant. So - why the difference? How can they all claim the same capabilities in the datasheet and still be this different?