Hall Effect Sensor doesn't seem to work correctly

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petespaco
 
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Hall Effect Sensor doesn't seem to work correctly

Post by petespaco »

I just bought 5 US5881 Hall Effect Sensors. The last ones I bought were marked "U58 316" and they worked as I expected.
These are marked "U58 417" and they seem to work backwards, and only cause a change of about 1/2 of a volt. Are they different?

Pete Stanaitis
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Franklin97355
 
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Re: Hall Effect Sensor doesn't seem to work correctly

Post by Franklin97355 »

I'll check.

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adafruit2
 
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Re: Hall Effect Sensor doesn't seem to work correctly

Post by adafruit2 »

the last 3 digits are the date code (see http://www.melexis.com/Asset/US5881-Dat ... -4824.aspx for packaging details)
its the exact same product we have purchased for 8 years or so :/

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petespaco
 
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Re: Hall Effect Sensor doesn't seem to work correctly

Post by petespaco »

Thank you for your reply. But now I am really stumped!
Here's the situation:
With the datasheet in front of me to make sure that I am looking at the "branded" side of the device and counting 1, 2, 3 from the left:
I connect pin 1 to 5 volts.
I connect pin 3 to ground.
I connect a 10K ohm resistor from 5 volts to the output, pin 2..
A digital voltmeter connected between ground and the output reads about 0.5 volts.
I bring the south pole of a magnet very close to the branded side of the Hall Effect sensor. The digital voltmeter reading DROPS to about 0.05 volts.
I remove the magnet and the digital voltmeter reading returns to 0.5 volts.

It appears to me that the device is "stuck" in the "on" position.
The same thing happens with 3 of the devices that I just bought.

What am I doing wrong?

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petespaco
 
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Re: Hall Effect Sensor doesn't seem to work correctly

Post by petespaco »

Boy, do I ever feel dumb! I'll bet I read that datasheet 10 times and I still got the pinout wrong.

The problem, of course, was all ME!. I was didn't realize that pin 3 is the output for the UA case. I was looking at the SE case pinout.
I had gotten it right a month or so ago when I hooked up my first one, but all those connections were buried in black tape, so it wasn't easy to tell what I had done.

Sorry to have bothered you,
Pete Stanaitis
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Franklin97355
 
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Re: Hall Effect Sensor doesn't seem to work correctly

Post by Franklin97355 »

No worries. I've done that on several chips.

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