Magnet Polarity Tester

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Hougaarden
Beiträge: 31
Registriert: Mittwoch 19. September 2018, 10:10

Magnet Polarity Tester

Beitrag von Hougaarden » Sonntag 22. März 2020, 10:04

A very simple but very useful magnet tester.
A North-pole in front of the APX9141 makes the red LED light up
A South-pole makes the green LED light up.
I bought the APX9141 very cheap on ebay (about 4€ for 10 pieces).
Dateianhänge
Magneet polariteit tester.LM4
(115.46 KiB) 20-mal heruntergeladen
Magneet polariteit tester (front).jpg
Magneet polariteit tester (front).jpg (203.54 KiB) 329 mal betrachtet
Magneet polariteit tester (back).jpg
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Magneet polariteit tester.LM4
(115.46 KiB) 18-mal heruntergeladen
Magneet polariteit tester (front).jpg
Magneet polariteit tester (front).jpg (203.54 KiB) 331 mal betrachtet

eBernd
Beiträge: 97
Registriert: Dienstag 14. Oktober 2008, 18:17

Re: Magnet Polarity Tester

Beitrag von eBernd » Sonntag 22. März 2020, 14:00

Hallo,

een fijn, klein gereedschap... :)
I've added the simple circuit diagram with measures for the sensitive area.
The question is whether parts are currently available from China...

Groetjes Bernd
MagnPolTester.GIF
MagnPolTester.GIF (8.48 KiB) 324 mal betrachtet

eBernd
Beiträge: 97
Registriert: Dienstag 14. Oktober 2008, 18:17

Re: Magnet Polarity Tester

Beitrag von eBernd » Sonntag 22. März 2020, 17:08

Hi again,

I found in a dutch forum https://www.circuitsonline.net/forum/view/130127 the problem, that one of the LEDs is always on (also without any magnet) because of the latching outputs. Can you confirm this?

Bernd

Hougaarden
Beiträge: 31
Registriert: Mittwoch 19. September 2018, 10:10

Re: Magnet Polarity Tester

Beitrag von Hougaarden » Dienstag 24. März 2020, 10:29

Bernd,
You are absolutely right about the latching outputs. You can avoid this by using two 3141 Hall sensors next to each other, one with the text in front and the other with the other side in front (the front detects one pole, the back the other).
If you are in a hurry to get a APX9141, I can send you one ore two by mail. Just send your address to my e-mail box (hougaarden@hotmail.com)

Regards, Wilfried

eBernd
Beiträge: 97
Registriert: Dienstag 14. Oktober 2008, 18:17

Re: Magnet Polarity Tester

Beitrag von eBernd » Dienstag 24. März 2020, 16:18

Hi Wilfried,

thank you for the confirmation. No, I am not in a hurry - as an ZZP (zelfstandig zonder personeel) there is nevertheless enough work to do at the moment ;) .
I will take some hall sensors from fans and examine first if "reverse/backwards" operation is sensitive enough (or if there is an shielding effect).
And whether the field of guitar PUs is strong enough...
But I will keep your offer in mind.

Regards, Bernd

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