5v hall sensor question

[PhoenixOSU]

so, i have been testing my hall sensors and when i apply 5V ot the sensors, I only get small fluctuations in the range of 10mv, they dont seem to be working 0 to 5 as they should, any idea why? my motor is a 6kw kelly hub.

 

[amberwolf]

If you've got 5V input to the sensors, (assuming they are 5V rated), then there ought to be a voltage swing of much more than 10mV. It might not be down to 0V or up to 5V, depending on whether they're logic output (comparator) or analog output (linear); the latter of which doesn't always go all the way to 0V or all the way up to 5V, but comes pretty close.

Either the sensors are not close enough to what they're sensing, or something is wrong with them. Perhaps they are not getting the 5V power *or* they are not grounded properly, due to a faulty connection somwhere. Could be a solder joint or could be a bad crimp or oxidized connection.

 

[dnmun]

the way i understand the hall sensor, red supplies power to the IC inside, black is grd. then you connect the output leg to 5V through a 1-10k resistor. when the hall sensor is toggled ON with the magnet, then the hall sensor IC sinks the current on the output leg through the IC to ground so the output leg drops to 0V. when you reset it with the magnet again, then the output is turned off and no longer sinks current and the voltage climbs up to match the 5V rail the 10k resistor is hanging from.

 

[monster]

i tested a motor halls sensors last night and i had this problem too. i used a 5V supply, that, open circuit went up to 8V. i didn't use a resistor on it either. ill try it again tonight with a resistor. maybe its because we are flodding the sensorsor something?

 

[PhoenixOSU]

Well, this is a brand new motor, so I doubt its broken, and if it is Kelly has good customer service (they do their best with their limited understanding of English). I think that the problem might very well be that I need a 10K pull up resistor on mine in order to get them to come up, meaning the outputs are open collector (same setup at an I2C communication interface). I'll retest tonight. As for getting 8V on the output with just a 5V input, maybe yours needs a pull down resistor?