I have just bought 3 linear hall effect sensrs of type SS495A. However, when I hook them up to my Arduino Uno's analog input, I get some really weird results.

I use a 5V power supply, and my output is 0.8V - always. It does not respond at all when I hold a magnet nearby.

According to the data sheet, the null output should be 2.5V, and it's sensitivity is 3.125 mV/G.

I have checked both the supply voltage and the output voltage with a multimeter, so I dont think there is anything wrong with my Arduino setup, and I have checked with 3 different sensors. I am really confused. Does anyone have a clue as to whats going on?

I bougth them from elfaelektronikk.no, Norways biggest suppier of electronics. They were brand new, and they were shipped in ESD protective bags so it would suprise med if all of them are fried.

I did not use any of the digital pins on the Arduino. I just connected to the 5V power pin, to the ground pin, and to the analog input (A0). I measured the voltage across V+ and Gnd pin on the sensor with a DMM, it was 5V. And I measured between GND and the output pin, which was 0.8V. This is the same result as I get from the analogRead.

  • \$\begingroup\$ I added a link to your sensor. Do you have a DMM (voltmeter) to check? If that gives 0.8 V then I'm guessing it's fried... ESD? Or bought on ebay? \$\endgroup\$ Feb 6, 2015 at 1:40
  • 1
    \$\begingroup\$ perhaps you connected 4.5V to the output, and you are measuring from the +supply input? \$\endgroup\$
    – HKOB
    Feb 6, 2015 at 13:14
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    \$\begingroup\$ Expanding on what @HKOB said, is it possible you have it flipped around backwards? (e.g. Output to 5V and VDD to analog input)? \$\endgroup\$
    – W5VO
    Mar 8, 2015 at 18:04
  • \$\begingroup\$ Photo of test setup? There's a schematic button on the editor toolbar. Also, that sensor is digital, not analog. Feed it to a digital input pin. \$\endgroup\$
    – Transistor
    Feb 13, 2016 at 16:27

1 Answer 1


One possibly is that your Arduino pins are set as outputs instead of inputs.

Try disconnecting the sensor from the Arduino and measuring the output of the sensor directly.


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