Issue with time-dependant conditional I/O control flow (Arduino UNO)

Question

We are working on a project to control the reaction of a system to a lever, whose position is monitored by two IR sensors at the ends of its travel, the Reward sensor and the Trigger sensor.

There are three modes of action:

Mode1: lever has to start at TriggerSensor, and a success is recorded if and when the lever is moved to RewardSensor

Mode2: lever starts at TriggerSensor and has to be held for 4 seconds. At the end of this interval a tone is played for 2 seconds, the reward interval. Within this 2 seconds, if the lever is moved to the RewardSensor, a success is recorded.

Mode3: same as Mode2, but the initial 4 second timeout is of random length.

We also want to use the following lines:

digitalWrite(TriggerSensorOut, digitalRead(TriggerSensorIn)); //This is to record to our computer the states of the trigger sensor digitalWrite(RewardSensorOut, digitalRead(RewardSensorIn)); //This is to record to our computer the states of the reward sensor

to constantly write the state of both sensors to our computer. However, this doesn't work as planned: there are delays between the execution of the mode functions (as described in full code below).Essentially, we are struggling to come up with a suitable way to time things correctly.

Please see full code below

// -----LIBRARIES

//#include <elapsedMillis.h>

// ----CONSTANTS (won't change)

const int TriggerSensorIn = 2;   //  Input from trigger sensor, LOW = broken
const int RewardSensorIn = 3;    //  Input from reward sensor, LOW = broken
const int ModeStateIn1 = 4;      //  Input 1 from switch to define paradigm mode
const int ModeStateIn2 = 5;      //  Input 2 from switch to define paradigm mode
const int RewardSignalOut = 12;   //  Output signal of reward, parallel taken off to counter module
const int ServoResetOut = 6;     //  Servo reset output signal
const int ToneOut = 10;          //  Audio stimulus
const int TriggerSensorOut = 7;  //  Output from trigger sensor for DAC board recording
const int RewardSensorOut = 8;   //  Output from reward sensor for DAC board recording

//------- VARIABLES (will change)

boolean backPressed = false;

int timeoutWindow = 4000;    // 4 second preliminary interval
int rewardWindow = 2000;    // 2 second reward interval

unsigned long currentMillis = 0;

//===============

void setup() {

  // initialise the digital pins as inputs and outputs

  pinMode(TriggerSensorIn, INPUT);
  pinMode(RewardSensorIn, INPUT);
  pinMode(ModeStateIn1, INPUT);
  pinMode(ModeStateIn2, INPUT);

  pinMode(RewardSignalOut, OUTPUT);
  pinMode(ServoResetOut, OUTPUT);
  pinMode(ToneOut, OUTPUT);
  pinMode(TriggerSensorOut, OUTPUT);
  pinMode(RewardSensorOut, OUTPUT);

}

//===============

void giveReward() {
  // This function is the protocol for recording a reward
  currentMillis=millis();
  digitalWrite(RewardSignalOut, HIGH);
  while (millis()>currentMillis+200) {
    digitalWrite(RewardSignalOut, LOW);
  }
}

//===============

void servoReset() {
  // This function is the protocol for resetting servos after a failed action
  currentMillis=millis();
  digitalWrite(ServoResetOut, HIGH);
  while (millis()>currentMillis+200) {
    digitalWrite(ServoResetOut, LOW);
  }
}

//===============

void mode1() {
  // This function is the protocol for controlling the system during mode 1, no time constraint on the action
  if (digitalRead(TriggerSensorIn == LOW)) {
    backPressed = true;

    if (backPressed == true && digitalRead(RewardSensorIn == LOW)) {
      giveReward();
      backPressed = false;
    }
  }
}

//===============

void mode2() {
  if (digitalRead(TriggerSensorIn == LOW)) {
    currentMillis=millis();
    while (digitalRead(TriggerSensorIn == LOW)) {
      while (millis() > currentMillis + timeoutWindow) {
        tone(ToneOut, 3000, 2000); 
        {
          goto rewardSeeking2;
        }
      }
    }

rewardSeeking2:
    currentMillis=millis();  // reset timer
    if (millis() < (currentMillis + rewardWindow) && digitalRead(RewardSensorIn == LOW)) {
      giveReward();
    }
    else if (millis() > (currentMillis + rewardWindow)) {
      servoReset();
    }
  }
}

//===============

void mode3() {
  timeoutWindow=random(1000,5000);
  if (digitalRead(TriggerSensorIn == LOW)) {
    currentMillis=millis();
    while (digitalRead(TriggerSensorIn == LOW)) {
      while (millis() > currentMillis + timeoutWindow) {
        tone(ToneOut, 3000, 2000); 
        {
          goto rewardSeeking3;
        }
      }
    }

rewardSeeking3:
    currentMillis=millis();  // reset timer
    if (millis() < (currentMillis + rewardWindow) && digitalRead(RewardSensorIn == LOW)) {
      giveReward();
    }
    else if (millis() > (currentMillis + rewardWindow)) {
      servoReset();
    }
  }
}

//===============

void loop() {

  digitalWrite(TriggerSensorOut, digitalRead(TriggerSensorIn));  //This is to record to our computer the states of the trigger sensor
  digitalWrite(RewardSensorOut, digitalRead(RewardSensorIn));  //This is to record to our computer the states of the reward sensor


  if (digitalRead(ModeStateIn1) == LOW && digitalRead(ModeStateIn2) == LOW) {
    // Using the two mode selective switches to define mode1
    mode1();
  }

  else if (digitalRead(ModeStateIn1) == LOW && digitalRead(ModeStateIn2) == HIGH) {
    // Using the two mode selective switches to define mode2
    mode2();
  }

  else if (digitalRead(ModeStateIn1) == HIGH && digitalRead(ModeStateIn2) == LOW)  {
    // Using the two mode selective switches to define mode3
    mode3();
  }
}

//===============END

Answer 1

This is a snippet of how I would refactor the code:

void mode3() {
  int timeout = millis() + random(1000,5000);
  while (digitalRead(TriggerSensorIn == LOW) && 
         millis() < timeout) {
  };
  if (digitalRead(TriggerSensorIn == LOW) && 
         millis() > timeout) {
     tone(ToneOut, 3000); 
     timeout = millis() + rewardWindow;
     while (millis() < timeout)
       if (digitalRead(RewardSensorIn == LOW)
         giveReward();
  }
  noTone();
}

....

void loop() {
  // This is to record to our computer the states of
  // the trigger sensor
  digitalWrite(TriggerSensorOut, digitalRead(TriggerSensorIn));  

  // This is to record to our computer the states of
  // the reward sensor
  digitalWrite(RewardSensorOut, digitalRead(RewardSensorIn));  


  int msin1 = digitalRead(ModeStateIn1);
  int msin2 = digitalRead(ModeStateIn2);

  if (msin1 == LOW)
      if (msin2 == LOW)
          mode1();
      else
          mode2();
  else if (msin2 == LOW)
    mode3();
}

But I think you should first try to write it down in plain English and verify that at least that algo works. Then you can think how to transpose it into code.