Externally powering a Hall Sensor

[dsteinschneider]

Hi Rob,

The graphic you posted ("Correct") appears to place the sensor with the beveled side down (left side of graphic where South pole of magnet travels down to the chip laying "flat").

I have the beveled side facing the magnet. I think my sensor is working OK but checking with you if I should have placed the flat side facing the magnet.

Thanks for all your advice!

[MisterE]

Hi Rob,

The graphic you posted ("Correct") appears to place the sensor with the beveled side down (left side of graphic where South pole of magnet travels down to the chip laying "flat").

I have the beveled side facing the magnet. I think my sensor is working OK but checking with you if I should have placed the flat side facing the magnet.

Thanks for all your advice!

I see that this is directed to Rob, but I may also be able to help based on my recent experience. The DRV5056A1QLPGM (a TO-92 form factor) hall sensor has a beveled side which is intended to face the South pole of a magnet. When the S pole approaches it, the voltage will rise from baseline of about 0.6V to VCC. The sensor shown in Rob's "Correct" image is very similar but has a different form factor. It is the SOT23 variant. Given that its solder points face down, the side that is "up" relative to that should face the S pole of a magnet as shown in that image. Having said all this, with the DRV5056A1QLPGM, you can reverse the polarity, as I have tried, and this will reverse the voltage direction. It will start at 0.6V and go DOWN (vs up) to a low of about 0.1V, depending on distance and your magnet's strength. FWIW, Hall Sensors can be, and are, implemented in alternative applications with lateral polarity, as shown in the right image. However, in that orientation the effect is non-linear with respect to distance from the magnet. In hi hat applications, linear response is preferred, particularly given that you can modify the effecctive response to your heart's desire in the eDRUMin Control application.

In effect if you're using the DRV5056A1QLPGM with the eDRUMin, face the S pole to the beveled side and voltage goes UP when the magnet gets closer. This requires the eDRUMin "invert" option is selected so that, when you press the pedal down and voltage goes up, the apparent pedal position goes down on the screen in line with your foot position.

Hope this helps.

[MisterE]

Hi Rob,

The graphic you posted ("Correct") appears to place the sensor with the beveled side down (left side of graphic where South pole of magnet travels down to the chip laying "flat").

I have the beveled side facing the magnet. I think my sensor is working OK but checking with you if I should have placed the flat side facing the magnet.

Thanks for all your advice!

I see that this is directed to Rob, but I may also be able to help based on my recent experience. The DRV5056A1QLPGM (a TO-92 form factor) hall sensor has a beveled side which is intended to face the South pole of a magnet. When the S pole approaches it, the voltage will rise from baseline of about 0.6V to VCC. The sensor shown in Rob's "Correct" image is very similar but has a different form factor. It is the SOT23 variant. Given that its solder points face down, the side that is "up" relative to that should face the S pole of a magnet as shown in that image. Having said all this, with the DRV5056A1QLPGM, you can reverse the polarity, as I have tried, and this will reverse the voltage direction. It will start at 0.6V and go DOWN (vs up) to a low of about 0.1V, depending on distance and your magnet's strength. This is not a useful dynamic range overall, whereas the intended S-to-bevel orientation offers about 2V of range.

FWIW, Hall Sensors can be, and are, implemented in alternative applications with lateral polarity, as shown in the right image. However, in that orientation the effect is non-linear with respect to distance from the magnet. In hi hat applications, linear response is preferred, particularly given that you can modify the effective response to your heart's desire in the eDRUMin Control application.

If you're using the DRV5056A1QLPGM with the eDRUMin, face the S pole to the beveled side, and you'll see that voltage goes UP when the magnet gets closer. This requires the eDRUMin "invert" option is selected, so that, when you press the pedal down and voltage goes up, the apparent pedal position goes down on the screen - in line with your foot position.

Hope this helps.

[dsteinschneider]

Hi @MisterE,

That answers my question - thanks for the answer!

Doug