anlogRead...¿hall sensor?

Using Arduino Project Guidance
#1

hi guys
i am trying to get an "analograd" from a hall sensor, have a few here diferent types.
as digital read i get 0 or 1 thats ok, but what i want is to read the proximity of the magnet, how can this be done? the hall sensor space is critical as it will go in a very small place
thanks

the current code is this one, i have replaced digital with analog and it only toses some numbers

const int hallPin = 3;     // the number of the hall effect sensor pin
const int ledPin =  LED_BUILTIN;     // the number of the LED pin
// variables will change:
int hallState = 0;          // variable for reading the hall sensor status

void setup() {
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);      
  // initialize the hall effect sensor pin as an input:
  pinMode(hallPin, INPUT); 
  Serial.begin(9600);    
}

void loop(){
  // read the state of the hall effect sensor:
  hallState = analogRead(hallPin); // testing
  Serial.println(hallState);
}
#2

If the sensor is outputting a digital signal (is it ?) then you cannot expect to read an analogue signal from it

Please provide a link to the sensor being used

#3

the sensors i have are these

3144 729

503 722

49e 924bc

#4

What controller are You using? If it is an UNO reading the pin the way You do will give just "0" or "1".
Try connecting the Hall sensor to an analog input like A0, A1..... and run Your sketch. Declare hallPin as "A0".

#5

Maybe OP did connect it to A3, and just called it "hallPin = 3;"
The compiler knows that you meant A3 when you do an analogRead.

To minimise confusion, you should call it A3 from the start.
const byte hallPin = A3;

Leo..

#6

@Wawa
Thanks!
I think compilers are suspect resources. One never knows what they will do.... Some 45 years ago the Gothenburg University Computer Central set up a compiler test team, in order to keep key-happy students away from taking over the entire IBM360, using a bug in the "set priority function".... The entire system including the registers for the entire University was in the hands of some students.
What came out of the project I don't know.

#7

hi
thanks for all the info
have tested it, i do get analog readings now but still all or nothing, i dont get a modulation...progressive increase and decrease as magnet is close or further of

thaaanks

#8

controller is a nano

#9

Danny1000:
the sensors i have are these

3144 729

503 722

49e 924bc

You should have used click-able links.

Google tells me that the first one could be a switch (digital).
The second one is a phone number.
The third one could be the one with an analogue output.
Leo..

#10

I picked up a project from somewhere that used a Hall sensor and an electro magnet in order to keep a load floating in the air. That sensor was definatly an analog Hall sensor. Maybe there are digital ones too.
You replied in #2 but is that the name of the sensor? It looks like some companies partnumbers.

#11

@Wava. A big laughter, The second one is a phone number.

#12

in the description says
AH3503 linear hall effect

the other one
49E hall element OH49E SS49E

wi the Ax pins and analog read should this be a increasing/decreasing read? thanks again

#13

What do mean by "increasing/decreasing" read? I don't understand that.

#14

The AH3503 seems OK.
Should work with this test sketch (untested).
It reads both polarities.

const byte hallPin = A0; // AH3503 sensor connected to A0 5volt and ground
const int offset = 512; // calibrate zero
const float span = 0.3617; // calibrate A/D > mT
float value;

void setup() {
  Serial.begin (9600);
}

void loop() {
  value = (analogRead(hallPin) - offset) * span;
  Serial.print("Value: ");
  Serial.print(value, 1);
  Serial.println(" mT");
  delay(500);
}

Don’t feel like wading through dozens of Honeywell sales pages to find the 49E sensor data.
Leo…

#15

hi Thanks
this has worked! now i get reading depending on the magnets position
i have notices if i leave it reading (test done without magnet) the values tend to creep up, once magnet is on and off the value gets back to its initial value and then creeps up again, how can i avoid this? in the hall circuit a resistor is provided.

thank you all again!!

#16

Greate! Maybe You can Google about the fundamentals, basics etc. about Hall sensors? Hopefully some more experienced helper pops up and tells what it’s all about.

#17

Danny1000:
in the hall circuit a resistor is provided.

Why?
That might be needed for a digital (switch) hall sensor with open collector, but not for this analogue one.

Did you have to change that '512' value, to get it to print about zero without a magnet near?
And is that zero point drifting.
By how much, and in what time frame.

Danny1000:
once magnet is on and off...

What do you mean with that.
Are you using an electro magnet?
Leo..

#18