wiring two Hall sensors to one arduino input

Other Hardware General Electronics
1

Greetings,
I was wondering if it is possible to wire two Hall sensors on a single Arduino digital or analog input.

Rationale: I have two Hall sensors A3144 (very close one to each other) on a pad, to detect the presence of a magnet;
the activation of at least one sensor is enough for me to state that the magnet is close to the pad.
I would like to use only one Arduino input. Is it possible to arrange the two sensors in an hardware configuration to produce a logic 'OR'?
In this link the configuration I would like to have (I did not tried it).

Thanks,
Valerio

2

Since the A3144 is an open collector switch you can do the "wired OR" with them. I set up my Uno with 2 A3144 switches and the following code to test. I get a LOW when either sensor is in the magnetic field (of the proper polarity) and a HIGH when the magnet is away. Circuit is wired like your fritzing diagram except I use digital pin 4 (A3144 is a switch, a digital function) and 10K pullup resistors.

const byte hallPinA = 4;

void setup()
{
   Serial.begin(115200);
}

void loop()
{
   static unsigned long timer = 0;
   unsigned long interval = 200;
   if (millis() - timer >= interval)
   {
      timer = millis();
      Serial.println(digitalRead(hallPinA));
      Serial.println();
   }
}

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3

Really thanks, I can confirm it works perfectly. I managed to arrange 3 hall sensors, using a single Arduino digital input.
Courteously,
Valerio

4

Open collector outputs driving a pull-up resistor are technically wired-AND. The output is HIGH only if both devices are outputing HIGH.

However if you use them active-LOW, then its wired-OR, logically if not physically...