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TMAG5173-Q1: 3D Hall Effect Sensor Application

Nicolas Fong
Prodigy 10 points
Part Number: TMAG5173-Q1
Other Parts Discussed in Thread: TMAG5273, TMAG5170, TMAG3001

Tool/software:

I’m looking to source a Hall Effect sensor that can detect combinations of multiple magnets at different positions (not just perpendicular to the sensor). Please see attached for a high-level diagram describing the application.

Is it possible to use a single hall effect sensor to detect whether different combinations of multiple magnets are in certain positions based on the measured total magnetic field strength? For example, based on the diagram, some scenarios I am looking to track are:

  1. MAG A is present, MAG B and MAG C are absent
  2. MAG B and MAG C are present, MAG A is absent
  3. MAG C is present, MAG A and MAG B are absent

Sensitivity is also a concern, as some magnets may be relatively far from the hall effect sensor or behind material layers as denoted in the drawing. The surface fields of the magnets are each around 4,000 Gauss, though some may change in the final design. Current draw is another consideration – ideally the sensor would be lower power or have a low-power mode.

From some preliminary research, I found TMAG5170-Q1, TMAG5273, and TMAG5173-Q1. Please let me know if there are any sensors that may be viable for this application or if you have any questions.

  • 0
    TI__Mastermind 21120 points

    Nicolas,

    A 3D Hall-effect sensor will detect the composite magnetic field at the sensor location.  As the three magnets are brought close to one another, their fields will interact, and you may be able to make system level decisions based on the observations if the cases provide unique field conditions. TMAG5170, TMAG5173, TMAG5273, and TMAG3001 are all 3D sensors that might be considered for what you are attempting.

    Looking at the ranges for Mag A and Mag C it appears that they are close enough to expect measurable inputs from most magnet sizes.  The strength of the field will depend on size, material, and grade of the magnet.  For all magnets, however, the field diminishes exponentially as the range increases.  Mag B is at a range of 10cm, and so I would expect to see very little measurable field unless the magnet is moved closer.

    Thanks,

    Scott