Trying to use magnet sensor NVE AFL006

Using Arduino Sensors
1

Hello -

I recently purchased a GMR magnetic sensor, the NVE AFL006. Here's the data sheet:

I paid someone to solder it onto a breakout board for me because I'm not very good with a soldering iron.

I've got it connected to a 1.6v power supply (via a buck converter) on pin 6 (opposite of the dot), then the ground on pin 3. I've connected my voltmeter to pin 4 and I keep waving a magnet back and forth in front of the sensor with no results.

Any ideas what I might be doing wrong? Shouldn't I see some reaction on the OUT pin via the voltmeter?

Thanks!
Matt

2

elveax:
Hello -

I recently purchased a GMR magnetic sensor, the NVE AFL006. Here's the data sheet:

https://www.nve.com/Downloads/AFLxxx-xx_Data_Sheet.pdf

I paid someone to solder it onto a breakout board for me because I'm not very good with a soldering iron.

I've got it connected to a 1.6v power supply (via a buck converter) on pin 6 (opposite of the dot), then the ground on pin 3. I've connected my voltmeter to pin 4 and I keep waving a magnet back and forth in front of the sensor with no results.

Any ideas what I might be doing wrong? Shouldn't I see some reaction on the OUT pin via the voltmeter?

Thanks!
Matt

The data sheet you referred to says the output pin is a SINK. So it has to have some voltage applied TO it that will become zero when the magnet switches the device. Perhaps the ohmmeter will show something if connected correctly and it's voltage is enough to make the chip work.

Paul

3

Ah, OK, that makes sense I think. I didn't know the distinction between the sink and source type outputs.

So does that mean I need to run my 1.6v supply to VCC and OUT? And that the voltmeter will show it to drop to zero when the magnet approaches?

4

Update: I tried this out and I think I'm getting some results, just not what I expected...

(forgive my terrible way of describing what I'm seeing...)

I've got my voltmeter set to DCV 2V. This means when I check the output from my buck converter, it reads 1.229. With power running to the VCC and the OUT, when I approach with the magnet (at about 6 inches away, which is about right for this sensor), it drops to 1.208. If I back up, it goes up to 1.229 again.

So, I guess in my final schematic, I'd need to hook this up to the analog pin on the Arduino and just flag on that subtle change?

5

Update to the update:

I connected the VCC to the OUT pin with a 5k1 resistor (and later a 100k resistor...), and now I can see that if I have a voltmeter connected to the OUT pin as I approach with the magnet, the voltage drops to 0, then raises back up as I back away. So, working as expected!

But (forgive my stupidity), I still can't get the Arduino to detect it. I connected the OUT pin to 13 on the Arduino. Then, I used this code:

int pinState;

void setup() {
  pinMode(13, INPUT);
  Serial.begin(9600);

}

void loop() {
  pinState = digitalRead(13);
  Serial.println(pinState);
  delay(500);
}

It just reads 1 the whole time. If I move the jumper to a ground connection, it drops to zero. But, if I wave the magnet over it, even though I see the voltmeter on the same connection drop to zero, pin 13 still reads 1. What gives?

6

Set the pin to input pullup.

Paul

7

Correct! I was just coming to post that I finally got it working in full.

For anyone else trying to do the same thing:

Resistor between VCC and OUT pin, then OUT pin to Arduino INPUT_PULLUP pin. Voltage drops to zero as the magnet gets within 6 inches or so. Works great!

Thank you everyone!!

8