UNIPOLAR HALL SENSOR QUESTIONS ?

[magnetman12003]

Can anyone answer a few questions about the unipolar hall sensor?

If placed within a extremely powerful South pole field will a south pole sensitive hall sensor only work if it IS FACING UPWARDS SEEKING A SOUTH POLE FIELD TO TURN ON AND OFF?   Or will the extremely powerful south pole field that its placed in activate the sensor anyway regardless if the sensor is placed facing up and directed away from that field?

All comments appreciated.  I am constructing a radical pulse motor unlike anything ever seen before that should run for days on end just like inexpensive desk top toys do.  Extremely efficient and my larger version will be able to power other devices as well.   Will post when finished.

[TinselKoala]

I just tested one of these:
https://www.sparkfun.com/products/9312
which is a unipolar _latching_ type HE sensor with some smarts built in. It turns on with one polarity and turns off with the other polarity and does not "false trigger" like I think you mean in your question. I tested it with some very strong N52 magnets.

You should try the experiment yourself with your particular HE sensor and whatever magnetic field you choose to use. Different sensors may behave differently depending on construction, how much extra stuff they have, latching vs. non-latching, etc.

The only other type of HE sensor I have on hand is a ratiometric linear HE sensor from Allegro, the A3503. Its output depends on the strength and "direction" of the field lines passing through it and it also will not "false trigger". But this one doesn't apply to your question.

[magnetman12003]

I just tested one of these:
https://www.sparkfun.com/products/9312
which is a unipolar _latching_ type HE sensor with some smarts built in. It turns on with one polarity and turns off with the other polarity and does not "false trigger" like I think you mean in your question. I tested it with some very strong N52 magnets.

You should try the experiment yourself with your particular HE sensor and whatever magnetic field you choose to use. Different sensors may behave differently depending on construction, how much extra stuff they have, latching vs. non-latching, etc.

The only other type of HE sensor I have on hand is a ratiometric linear HE sensor from Allegro, the A3503. Its output depends on the strength and "direction" of the field lines passing through it and it also will not "false trigger". But this one doesn't apply to your question.

Hi TinselKoala,
Thanks for your input to my questions.  I have decided to use a Honeywell 785-SS443R unipolar hall
sensor after I contacted Honeywell engineering directly.  This particular sensor is south pole sensitive on ONE side and works in an on - off fashion.  The south pole flux lines have to be directed STRAIGHT into the sensor to activate it.
It wont work any other way even if placed into a powerful south pole magnetic field  that's coming up from BEHIND the sensitive area. Its the perfect choice for me with what I have in mind.  This bi polar hall sensor is NOT the latching kind where you need a magnetic pole to turn it on and the opposite pole to turn it off.

[magnetman12003]

I just tested one of these:
https://www.sparkfun.com/products/9312
which is a unipolar _latching_ type HE sensor with some smarts built in. It turns on with one polarity and turns off with the other polarity and does not "false trigger" like I think you mean in your question. I tested it with some very strong N52 magnets.

You should try the experiment yourself with your particular HE sensor and whatever magnetic field you choose to use. Different sensors may behave differently depending on construction, how much extra stuff they have, latching vs. non-latching, etc.

The only other type of HE sensor I have on hand is a ratiometric linear HE sensor from Allegro, the A3503. Its output depends on the strength and "direction" of the field lines passing through it and it also will not "false trigger". But this one doesn't apply to your question.