Starter Sketch for Flicker Fusion A/D project

ArduinorReadPotStarter.uno

/*
  AnalogReadSerial

  Reads an analog input on pin 0, prints the result to the Serial Monitor.
  Graphical representation is available using Serial Plotter (Tools > Serial Plotter menu).
  Attach the center pin of a potentiometer to pin A0, and the outside pins to +5V and ground.

  This example code is in the public domain.

  https://docs.arduino.cc/built-in-examples/basics/AnalogReadSerial/
*/

// Using names instead of "magic numbers" is a good practice
#define POT_PIN A0
#define LED_PIN 3

// Utility routine to hack the automatic scaling off for the plot
void plotSpeed (float max_value, float sensorValue)
{
  Serial.print(0); // To freeze the lower limit
  Serial.print(" ");
  Serial.print(max_value); // To freeze the upper limit
  Serial.print(" ");
  Serial.println(sensorValue); // To send all three 'data' points to the plotter
}

// the setup routine runs once when you press reset 
// or upload code
void setup() {
  // initialize serial communication at 115200 bits per second.
  // Be sure to set the serial plotter to this same speed.
  Serial.begin(115200);
  pinMode( LED_PIN, OUTPUT ) ;
}

// the loop routine runs over and over again forever:
void loop() {

  // Don't worry, this gets changed to the measured value when
  // you complete the sketch.  This just makes the sketch blink
  // the LED for your intial testing.
  int led_on_time = 100 ;  

  //**********************************************************
  // Insert code to read the input on analog pin 0:
  //**********************************************************

  //**********************************************************
  // Insert code to
  // Scale raw a/d (0-1023) to 0-100 because 100ms is 
  // plenty for the flicker experiment
  // Using the Arduino map( ) method is eas. Assign the result to
  // the led_on_time variable
  //**********************************************************
  
  // Here's the actual ON/OFF logic.
  digitalWrite( LED_PIN, LOW) ;
  delay( led_on_time ) ;
  digitalWrite ( LED_PIN, HIGH ) ;

  // convert period of delay to freq in Hz
  float freq = 1.0 / ((( float ) led_on_time) / 1000.0) ;

  // print out the value you read, forcing auto-scale off in the
  // serial plotter
  plotSpeed( freq, 100 ) ;
  
}