Looking for the right linear hall sensor for a speceific application

I need a sensor that will be able to tell whether a marker (e.g. a magnet, which is hand held) is nearby (e.g. distance <3mm), how closed is it (with a few mm accuracy), and most important of all - whether it’s moving or resting (= the eye can’t see any movement).

I thought about a linear hall sensor with a magnet but what sensor and what magnet type will give me the accuracy that I need? I saw that the SS49E Hall Effect sensor works only for distances > 5mm which is not optimal but how accurate is it? Will it catch 3mm changes in the location?

B/c I have the magnet in my hand I can’t use PIR movement and IR proximity sensors(*). B/c of the small distances I can’t use ultrasonic sensors. Camera sensor is possible solution which is expensive and cumbersome (the size of a hall sensor is optimal) so I hope to find better solution.

(*) if there’s a good distance/motion sensor that will track any obstacle in these ranges it’s better then no solution at all.

Honeywell and Allegro both make dozens of hall effect sensors. You fail to mention the field strength and most linear hall effect sensors are specified using Gauss. We just can't say magnet without specifying the field strength.

LASER distance sensors are also popular but when you start splitting hairs they don't come along low budget. Micro-Epsilon comes to mind.


We just can't say magnet without specifying the field strength.

Yes, I am looking for a combination of a specific hall sensor and a specific magnet that will give me the accuracy that I need.

So rather than look at magnets, understand Gauss and hall sensor types and sensitivity you want someone else to do all of your legwork. I think I understand. Have you even looked at Honeywell and Allegro hall sensors? Have you even looked at linear sensors? You mention a distance of 3.0 mm with a few mm accuracy?


What do you think to use an Event camera?

I don't know your setup and I can't see your setup. Have you looked at linear position sensors or string pot sensors or similar means of sensing distance? You also have made no mention of what you plan to interface the sensor to?


Thanks for your ideas, most of them were new for me.

The data that is important to me is the 3-dimentional distance between too points and the event "marker x is not moving". Space is at premium so using two sensors (event camera for stillness and a distance sensor) is not so good. As lines of equi field strength are not ovalic a Hall sensor may not work so well.

I can't tolerate any drag so a linear pot and a string pot won't help me.
Short range VCSELs seem accurate but I need a sensor that will be sensitive only for the marker and not for the whole hand.
A Pixy camera is the expensive solution - its resolution is and refresh time are good enough for me. And I guess event cameras are even more expensive.

As for Allegro Hall sensors I found lot's of data sheets but no simple arduino implementation.

So in the case there're no other possibilities maybe I'll have to try to relax some of the demands. I mainly look for simple implementations of simple Hall and Allegro sensors to see how well they perform.