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Author Topic: Pressure Sensor using hall effect  (Read 497 times)
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I have a pressure sensor that uses a spring actuated hall in relation to a low and high pressure port. My question is: if the spring the magnet is actuated on is slightly magnetic, will that affect the performance/reaction of the hall sensor?

Thanks for the help.
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Can you give a link to that sensor ?

Is a magnet attached to the spring ? I assume it is, otherwise the hall sensors can't detect it.
If so, the magnet is far more stronger than the magnetism of the spring.

Is the spring metal ? perhaps it is plastic.

With a reed relay, the metal contacts could be magnetised. That could result into a failing relay. But a hall sensor itself can not be magnetised. The hall sensors (as on/off switches) are also not very sensitive, they need a magnet nearby to switch.
If you want to measure small magnetism, use a HMC5883L magnetometer (compass) as a metal detector. That is a total different order of detection level.
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Is there a magnet inside ? I can't read about it. I would like to know what kind of magnet.

The PDL-1... type has an spiral spring of steel.
So that spring can be magnetised. Allthough I think that a magnet is far stronger. The influence of the spring would be very little.
If there is a normal magnet inside, the magnetism of it is getting dim over a number of years.
For example, if you have a number of these calibrated and check upon them after 5 years, I wouldn't surprise me if they were off by 20%. But that is just a guess.

If you want to read a endless document about it, search for "Honeywell hallbook" (HALL EFFECT SENSING AND APPLICATION).
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