Hello,

I ran out of analog inputs on my Arduino Nano, so trying RCtime with a 10k linear potentiometer.
The circuit I'm using is attached.

The code I'm using comes from the Arduino tutorial example, however, I am trying to modify the code with the constrain() to keep the results within a set
of values lie so;

void loop()                     
{

   Serial.println( RCtime(sensorPin) );
   delay(10);

}

long RCtime(int sensPin){
   long result = 0;
   pinMode(sensPin, OUTPUT);       // make pin OUTPUT
   digitalWrite(sensPin, HIGH);      // make pin HIGH to discharge capacitor - study the schematic
   delay(1);                                  // wait a  ms to make sure cap is discharged

   pinMode(sensPin, INPUT);        // turn pin into an input and time till pin goes low
   digitalWrite(sensPin, LOW);     // turn pullups off - or it won't work
   while(digitalRead(sensPin)){    // wait for pin to go low
      result++;
      constrain(result, 0, 3); //keep result within a range of 0 to 3. <----- will putting constrain() here work as assumed?
   }
   return result;                   // report results   
}

Sincere thanks for any advice/help. Appreciated.
TonyAm

 

Constrain basically sets limits of the value to be reported. If "result" is greater than 3, it will return 3. If "result" is less than zero, it will return zero.
This function does not modify the original value passed to it, you have to use it as a function and assign the returned result to another variable.
See code example:
https://docs.arduino.cc/language-reference/en/functions/math/constrain/

You should have something like:
result = constrain(result, 0, 3);

 

Ok, thank you very much.