Hall sensor application

I’m new to the world of magnetic sensors need some help understanding and find the right components for a HALL (?) sensor application. The Idea is to measure the position of a magnet with diameter of 5mm and 1-2mm thick.
The magnet will have a Zero point and from there it can move 4mm to 6mm.
I need to measure if the magnet is at the Zero-point as a more or less digital value and then I need to measure with some precision if the magnet is in the range 4-6mm. Preferably with 0.3mm resolution or better.

The HALL-sensor must be positioned 5mm from the magnets travel path, but anywhere along the path.

I need suggestions for both the magnet and the sensor.

Hi bosan,

Welcome to the Tech Forum. A few questions to help pare down the options:

  • Will the magnet be moving in only one axis or more than one (X; X and Y; X, Y, and Z)?
  • Do you prefer an analog or digital output?
  • Do you need to measure rotation, too, or just translation?
  • Any particular reason for the specific form-factor of the magnet you specified?
  • Anything else you can tell us about your application which might help differentiate options?

Hi David_1528

Thank you for your response.

Lets say that the magnet is moving inside a tube following the tube direction and the sensor will be on the outsiede of the tube.

A small size important. I believe a digital output will be easier for a small and simple design. A small microcontroller will recieve and calculat the position.

No rotation will be measured. Only the position alongside the tube.

The reason for the form is due to the mechanical implementation. The diameter of 5mm of the magnet is maximum but I believe it migt be possible to have it thicker than 1mm.

When it comes to the magnet. How acurate is the magnetic filed around the magnet and between different magnets.

Can the acuracy be icreased by using both z and x field of the sensor. (If a Hall sensor is the best choise)

I’m tinking of adding a second sensor on the oposite side of the tube for possibly cancel external magnet fields by summarising the values from the two sensors.

Hi bosan,

The sensors listed below are designed to measure linear displacement of a magnet. I can’t say for sure if a magnet of the size you are specifying would work at those distances. They both have multiple axes of Hall sensors, so they have higher performance than single sensor options.

TLV493DA1B6HTSA2 Multi-axis Hall sensor with I2C interface

MLX90374GDC-ABC-200-SP Multi-axis Hall sensor with PWM and SENT interfaces

Regarding magnets, we do not have any 5mm diameter x 1mm thickness options. Here is a list of options which are 2mm or thinner and which are 6mm or less in diameter.

Here is a larger list of magnets we carry with which you may want to experiment if the magnets linked to above prove inadequate from a field strength or dimensional perspective.