How does a 3144 Hall Effect Sensor Work

[nilaidevs]

I am using four 3144 Hall effect sensors and put them in a simple circuit with outputs at A1, A2, A3 and A4. The grounds of these sensors go to GND and the Voltage Inputs go to 5V. I am printing the output at half a second intervals. But I am getting a strange result. Without any magnet around the results are floating between 0 to 1023.

17:47:12.556 -> 1023,   1023,   1023,   1023
17:47:13.071 -> Current Pin values are 
17:47:13.071 -> 1023,   1023,   1023,   1023
17:47:13.587 -> Current Pin values are 
17:47:13.587 -> 627,   227,   200,   397
17:47:14.057 -> Current Pin values are 
17:47:14.057 -> 100,   0,   0,   120
17:47:14.568 -> Current Pin values are 
17:47:14.568 -> 25,   0,   0,   40
17:47:15.083 -> Current Pin values are 
17:47:15.083 -> 0,   0,   0,   12
17:47:15.552 -> Current Pin values are 
17:47:15.552 -> 0,   0,   0,   0
17:47:16.070 -> Current Pin values are 
17:47:16.070 -> 6,   37,   57,   77
17:47:16.579 -> Current Pin values are 
17:47:16.579 -> 423,   686,   665,   512
17:47:17.077 -> Current Pin values are 
 17:47:17.077 -> 865,   1023,   1023,   877
 17:47:17.593 -> Current Pin values are 
 17:47:17.593 -> 1012,   1023,   1023,   1023
 17:47:18.065 -> Current Pin values are 
 17:47:18.065 -> 1023,   1023,   1023,   1023
 17:47:18.587 -> Current Pin values are 
 17:47:18.587 -> 826,   527,   471,   569
 17:47:19.102 -> Current Pin values are 
 17:47:19.102 -> 143,   0,   0,   174
 17:47:19.564 -> Current Pin values are 
 17:47:19.564 -> 35,   0,   0,   51

However if I put a South pole on any one of their faces, the value becomes a 1 or 2 . In this example below I have put the magnet on the face of the sensor at A1 for two seconds and released it. The value was shown as 2 over that period of time.

17:27:07.678 -> 1023,   1023,   1023,   1013
17:27:08.193 -> Current Pin values are 
17:27:08.193 -> 325,   0,   0,   1013
17:27:08.668 -> Current Pin values are 
17:27:08.668 -> 2,   0,   0,   1017
17:27:09.180 -> Current Pin values are 
17:27:09.180 -> 2,   0,   0,   1010
17:27:09.682 -> Current Pin values are 
17:27:09.682 -> 2,   0,   0,   1013
17:27:10.197 -> Current Pin values are 
17:27:10.197 -> 2,   340,   529,   1013
17:27:10.666 -> Current Pin values are 
17:27:10.666 -> 2,   668,   1005,   1016
17:27:11.176 -> Current Pin values are 
17:27:11.176 -> 2,   666,   994,   1011
17:27:11.691 -> Current Pin values are 
17:27:11.691 -> 1023,   1023,   1023,   1012

Where I am going wrong? Or isn't 3144 not the right sensor? But I have seen examples that people are using it. One interesting point to note that, I havent used any resistor with it and directly used the sensor as it is, (in TO-92 packaging) as the datasheet tells me I can use it that way.

If you want to look at my simple code, here it. (Many thanks for helping this greenhorn)

const int Pin1 = A1; 
const int Pin2 = A2; 
const int Pin3 = A3;
const int Pin4 = A4;
int Pin1Status = 0;
int Pin2Status = 0;
int Pin3Status = 0;
int Pin4Status = 0;




void setup() {

  Serial.begin(115200);
  Serial.print("\nStart of Program\n");
  pinMode(Pin1,INPUT);
  pinMode(Pin2,INPUT);
  pinMode(Pin3,INPUT);
  pinMode(Pin4,INPUT);
  delay(3000);
}

void loop() {

 Serial.print("\nCurrent Pin values are ");
 Pin1Status = analogRead(Pin1);
 Serial.print("\n");
 Serial.print(Pin1Status);
 Serial.print(",   ");
 Pin2Status = analogRead(Pin2);
 Serial.print(Pin2Status);
 Pin3Status = analogRead(Pin3);
 Serial.print(",   ");
 Serial.print(Pin3Status);
 Pin4Status = analogRead(Pin4);
 Serial.print(",   ");
 Serial.print(Pin4Status);
 delay(500);
}  

[gilshultz]

@nilaidevs

3144 Hall effect sensors

Digital Output Hall-effect sensor · Operating voltage: 4.5V to 28V. Note the first two words "Digital Output" That indicates that it will output a digital low or high. In this case it is an open collector/drain and needs a pull up circuit. Read this, it will explain much better than I can in this small space. A3144 Hall Effect Sensor Pinout, Working, Alternatives & Datasheet. It is amazing what you can find with Google in a few seconds. My search term was "3144 Hall effect sensors" and this is the first hit I got.

[nilaidevs]

Thanks for clarifying that this has digital output. The internet is a weird place. The first tutorial video I came across to learn about types of Hall Sensors, I came across this video, which introduces 3144 as a linear unipolar analog Hall Sensor. And in the video he showed how to use it analog way.

HALL Effect SENSORS - Linear,UniPolar,BiPolar

I would like to know some linear unipolar Hall Sensor. Can you suggest any? Thanks again.

[gilshultz]

That is why we ask for the information we do, a lot of junk is on the internet. People will post anything just to get there name in print. You can use the analog inputs as digital and it will work with an external pull up resistor. As for recommending I cannot show preference to any supplier but with a bit of time and google you will find something. Check the data sheet for the part you find. I found several and the SS49E was the first true analog per its data sheet to show up.

[nilaidevs]

@gilshultz , I have put a 10K Ohm across A0 and V5V and likewise for A1 and A2. Working fine, but as a switch. 1-2 when magnet is present and 1023 when not. Thank you.

[flashko]

Instead of just watching the video, you should have read what it says below it.

3 types
Analog or Linerar sensor (A49E)
Unipolar Digital sensor ( WSH 130NL,, 3144 )
Bipolar Digital Sensor (WSH 130)

[gilshultz]

You got it, thanks for the feedback . You can try on a digital pin and if it is close to the Arduino using the internal pull up may work just fine. Just set it when you define it as an input with pinmode().