Liquid level detection

Hello Mike,

Thank you for using the TI forum. There are a few ways to do liquid level sensing with Hall sensors. Below are some ideas for you to consider, based on your system needs:

1. Flotation device on an axial arm with angle measurement
   1. Block Diagram: 
   2. You measure the angle of the magnet that changes with height of the flotation device
   3. Only need one sensor (most likely the DRV5055, but can use a DRV5056 if the angle range is small enough)
   4. Can use smaller magnet for larger fluid movement range
2. Floating magnet with linear Hall
   1. Block diagram with DRV5056:
      1. Magnet moves towards and away from the sensor
   2. Block diagram with DRV5055:
      1. Magnet moves next to the sensor
   3. Fluid measurement range/resolution restricted based on size/strength of magnet and sensor sensitivity (sometimes requires large magnets)
   4. Only need one sensor 

3. Floating magnet with Latches/Switches
   1. Block diagram:
   2. Detect specific liquid positions as a magnet passes each sensor
      1. Use latches with a sideways magnet if you want the sensors to stay active when the liquid is above that sensor (useful to know the liquid level region when the magnet is in between sensors)
      2. Use switches with the magnet facing the sensors if you only want to know when you have reached the specific desired liquid level and don’t care to know the liquid level region when the magnet is in between sensors

   3. Need a sensor for each liquid level position to detect
   4. can use smaller magnets