Help for analog signal on Arduino

Projects General Guidance
1

I have an Arduino Leonardo and I need to connect an analog signal to the AD port.

The analog signal comes from an external device.

The device signal has two pins: GND and CONTROL.

The signal basically has two low noise states.

CONTROL - GND
1.1 Volts
0 volts

My program does the following:

When:

CONTROL - GND PROGRAM
1.1 Volts Runs A
0 Volts Runs B

My question is the connection of this signal (device) to the AD port of the Arduino.

In my assembly I connect Device GND to Arduino GND and CONTROL to Arduino A0 port directly.

Would this be the correct way?

Should there be a few more components to protect the circuits or even have an AD port read with less chance of errors?

Att,

Alysson

2

Assuming the wire lengths are reasonably short & tidy, those connections shoukd be ok.

The next question is : should (a) and (b) run continuously during the high/low states, or only when the input state changes.

3

Just when input state changes. This signal looks like a "push-button".

4

This could be a function that acts like a digitalRead().

/*
  read an analogue input pin and return LOW or HIGH
  In:
    pin to read
  Returns:
    LOW if signal below 500 mV, else HIGH
*/
uint8_t readUnknownDevice(uint8_t pin)
{
  // read the ananlog input
  int x = analogRead(pin);

  if (x < 100)
  {
    // if reading below roughly 500 mV, return LOW
    return LOW;
  }
  else
  {
    // if reading not below roughly 500 mV, return HIGH
    return HIGH;
  }
}

You can use it e.g. like

void loop()
{
  Serial.print(F("Unknown device signal "));
  Serial.println(readUnknownDevice(A0) == LOW ? "LOW" : "HIGH");
}

I'll leave the state change detection to you. It can be implemented in loop() or in another function that you can call from loop().

Code compiles, not tested.

5

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