Magnetic field sensor - suggestion

[Jacek Pieczaba]

Posted on March 12, 2018 at 21:45

Hello,

I am planning to build a concept of level sensing system based on the magnetic field sensor ( ideally 3 axis ) which will be located on the bottom of the canister and flowing on the surface neodymium magnet. What Sensor you could suggest to be used for testing ( I am assume maybe the most sensitive and with digital front end baked-in in order to reduce noise to minimum ). 

The test will help me to determine how far sensor and magnet could operate giving an reliable information, and also what other factors could affect the readings. 

Thanks a lot in advnace

Jacek 

[Miroslav BATEK]

Posted on March 15, 2018 at 16:51

Please consider dependency of magnetic flux density vs distance.

Magnetic flux density of neodymium magnet is very high on the contrary the range on MEMS magnetometer is quite low.

[Jacek Pieczaba]

Posted on March 15, 2018 at 23:59

Understand... 

That is the reason I am looking for advice what type. Have run some tests using the HMC5883L on the bottom of the plastic canister , and with the floating small neodymium magnet on the surface of the water. I was able to get quite nice readings in the range to about 40-50cm from sensor to magnet. The only problem is like you mention the field is so strong that when the level is dropping signal increase very heavily so maybe different sensor could works better. 

Thanks a lot, and like I am mention earlier it is just exploration at this point of time potential technical solution. So maybe this idea is not an viable solution.