Practical Arduino C

Chapter 10: Extras

  1. Home
  2. Extras
  3. Chapter 10

Page 139

PWM colours breadboard layout

Page 140

void state1();
void state2();
void state3();
void state4();
void state5();
void state6();
void (*states[])(void) = {
  state1, state2, state3, state4, state5, state6
};
void setup() {
  Serial.begin(115200);
}
void loop() {
  for(int i = 0; i < 6; i++){
    states[i]();
  }
}
void state1() {
  if(Serial) {Serial.println("State 1");}
  delay(2000);
}
void state2() {
  if(Serial) {Serial.println("State 2");}
  delay(2000);
}
void state3() {
  if(Serial) {Serial.println("State 3");}
  delay(2000);
}
void state4() {
  if(Serial) {Serial.println("State 4");}
  delay(2000);
}
void state5() {
  if(Serial) {Serial.println("State 5");}
  delay(2000);
}
void state6() {
  if(Serial) {Serial.println("State 6");}
  delay(2000);
}

Page 141

#define C6  1047
volatile bool pedRequest = false;
const int RED_TRAFFIC = 8;
const int AMBER_TRAFFIC = 7;
const int GREEN_TRAFFIC = 6;
const int DONT_CROSS = 5;
const int CROSS = 4;
const int PED_BUTTON = 2;
const int PED_SOUNDER = 3;
void setup() {
  Serial.begin(115200);
  pinMode(RED_TRAFFIC, OUTPUT);
  pinMode(AMBER_TRAFFIC, OUTPUT);
  pinMode(GREEN_TRAFFIC, OUTPUT);
  pinMode(DONT_CROSS, OUTPUT);
  pinMode(CROSS, OUTPUT);
  pinMode(PED_BUTTON, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(PED_BUTTON), intHandler, FALLING);
}
void intHandler() {
  pedRequest = true;
}
void state1() {
  int leds[] = {
    RED_TRAFFIC, AMBER_TRAFFIC, GREEN_TRAFFIC,
    DONT_CROSS, CROSS};
  if(Serial) {Serial.println("Testing LEDs");}
  for (int i = 0; i < 5; i++) {
    digitalWrite(leds[i], HIGH);
    delay(500);
    digitalWrite(leds[i], LOW);
  }
  if(Serial) {Serial.println("Testing Sound");}
  for(int i = 0; i < 5; i++) {
    tone(PED_SOUNDER, C6, 250);
    delay(500);
  }
  noTone(PED_SOUNDER);
  if(pedRequest) {
    pedRequest = false;
    if(Serial) {
      Serial.println("Pedestrian Button Pressed");
    }  
  }
}

Page 143

void state2() {
  if(Serial) {
    Serial.println("State 2");
  }
  unsigned long startMillis = millis();
  digitalWrite(GREEN_TRAFFIC, LOW);
  digitalWrite(DONT_CROSS, HIGH);
  digitalWrite(AMBER_TRAFFIC, HIGH);
  do {
    
  }while((unsigned long)(millis() - startMillis) < 3000);
}

Page 143

unsigned long milliMe;
unsigned long stopVal = 2000ul;
unsigned long startVal = 0xFFFFFFFF; 
unsigned int target = 1000;
void setup() {
 Serial.begin(115200);
  startVal -= 10000;
  milliMe = startVal;
}
void loop() {
  unsigned long lastMilli = milliMe;
  for(int i = 0; i < 32767; i++) {
    milliMe++;
    if((unsigned long)(milliMe - lastMilli) >= target) {
      Serial.print("Simulated mills() at: ");
      Serial.print(milliMe);
      Serial.print(", lastMilli: ");
      Serial.print(lastMilli);
      Serial.println(" difference >= target");
      lastMilli = milliMe;
    }
    if(milliMe < startVal && milliMe > stopVal) {
      break;
    }
  }
}

Page 144

The complete program

#define C6  1047
#define BEEP 250
#define THRD_SEC 330
#define HALF_SEC 500
#define SECS_3 3000
#define SECS_2 2000
#define SECS_7 7000
#define SECS_6 6000
#define MAX_WAIT 10000
void state1();
void state2();
void state3();
void state4();
void state5();
void state6();
void (*states[])(void) = {
  state1, state2, state3, state4, state5, state6
};
volatile bool pedRequest = false;
const int RED_TRAFFIC = 8;
const int AMBER_TRAFFIC = 7;
const int GREEN_TRAFFIC = 6;
const int DONT_CROSS = 5;
const int CROSS = 4;
const int PED_BUTTON = 2;
const int PED_SOUNDER = 3;
void setup() {
  pinMode(RED_TRAFFIC, OUTPUT);
  pinMode(AMBER_TRAFFIC, OUTPUT);
  pinMode(GREEN_TRAFFIC, OUTPUT);
  pinMode(DONT_CROSS, OUTPUT);
  pinMode(CROSS, OUTPUT);
  pinMode(PED_BUTTON, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(PED_BUTTON), intHandler, FALLING);
}
void loop() {
  for(int i = 0; i < 6; i++){
    states[i]();
  }
}
void intHandler() {
  pedRequest = true;
}
void state1() {
  pedRequest = false;
  unsigned long startMillis = millis();
  digitalWrite(DONT_CROSS, HIGH);
  digitalWrite(GREEN_TRAFFIC, HIGH);
  digitalWrite(AMBER_TRAFFIC, LOW);
  while(true) {
    unsigned long currentMillis = millis();
    if(pedRequest) {
      if((unsigned long)(currentMillis - startMillis) >= MAX_WAIT) {
        break; // pedestrian request and minimum time condition met
      }
    }
  }
}
void state2() {
  unsigned long startMillis = millis();
  digitalWrite(GREEN_TRAFFIC, LOW);
  digitalWrite(DONT_CROSS, HIGH);
  digitalWrite(AMBER_TRAFFIC, HIGH);
  do {
  }while((unsigned long)(millis() - startMillis) < SECS_3);
}
void state3() {
  unsigned long startMillis = millis();
  digitalWrite(RED_TRAFFIC, HIGH);
  digitalWrite(AMBER_TRAFFIC, LOW);
  digitalWrite(DONT_CROSS, HIGH);
  do {
  }while((unsigned long)(millis() - startMillis) < SECS_3);
}
void state4() {
  unsigned long startMillis = millis();
  unsigned long lastMillis = startMillis;
  digitalWrite(RED_TRAFFIC, HIGH);
  digitalWrite(CROSS, HIGH);
  digitalWrite(DONT_CROSS, LOW);
  tone(PED_SOUNDER, C6, BEEP);
  while(true) {
    unsigned long currentMillis = millis();
    if((unsigned long)(currentMillis - lastMillis) >= HALF_SEC){
      tone(PED_SOUNDER, C6, BEEP);
      lastMillis = currentMillis;
    }
    if((unsigned long)(currentMillis - startMillis) >= SECS_7) {
      break; // timed end of state 4
    }
  }
  noTone(PED_SOUNDER);
}
void state5() {
  unsigned long startMillis = millis();
  unsigned long trafficMillis = startMillis;
  unsigned long pedMillis = startMillis;
  digitalWrite(AMBER_TRAFFIC, HIGH);
  digitalWrite(RED_TRAFFIC, LOW);
  digitalWrite(CROSS, HIGH);
  while(true) {
    unsigned long currentMillis = millis();
    if((unsigned long)(currentMillis - trafficMillis) >= HALF_SEC){
      digitalWrite(AMBER_TRAFFIC, digitalRead(AMBER_TRAFFIC) ^ 1);
      trafficMillis = currentMillis;
    }
    if((unsigned long)(currentMillis - pedMillis) >= THRD_SEC){
      digitalWrite(CROSS, digitalRead(CROSS) ^ 1);
      pedMillis = currentMillis;
    }
    if((unsigned long)(currentMillis - startMillis) >= SECS_6) {
      break; // timed end of state 5
    }
  }
}
void state6() {
  unsigned long startMillis = millis();
  unsigned long lastMillis = startMillis;
  digitalWrite(DONT_CROSS, HIGH);
  digitalWrite(CROSS, LOW);
  digitalWrite(AMBER_TRAFFIC, HIGH);
  while(true) {
    unsigned long currentMillis = millis();
    if((unsigned long)(currentMillis - lastMillis) >= HALF_SEC){
      digitalWrite(AMBER_TRAFFIC, digitalRead(AMBER_TRAFFIC) ^ 1);
      lastMillis = currentMillis;
    }
    if((unsigned long)(currentMillis - startMillis) >= SECS_2) {
      break; // timed end of state 6
    }
  }
}

Page 148

extern volatile unsigned long timer0_millis;
void resetMillis(){
  uint8_t oldSREG = SREG; // copy the status Register
  cli(); // disable interrupts
  timer0_millis = 0; // zero the millis counter
  SREG = oldSREG; // reset the status Register
}

Page 149 and page 150

#define BOUNCE_TIME 50
volatile bool pedRequest = false;
volatile bool suspRequest = false;
unsigned long suspenseTime = millis(); // used to debounce button
bool suspended = false;
const int RED_TRAFFIC = 8;
const int AMBER_TRAFFIC = 7;
const int GREEN_TRAFFIC = 6;
const int DONT_CROSS = 5;
const int CROSS = 4;
const int PED_BUTTON = 2;
const int PED_SOUNDER = 9;
const int REMOTE_SUSPEND = 3;


pinMode(REMOTE_SUSPEND, INPUT_PULLUP);
attachInterrupt(digitalPinToInterrupt(REMOTE_SUSPEND), suspHandler, FALLING);


void suspHandler() {
  unsigned long currentMillis = millis();
  if((unsigned long)(currentMillis - suspenseTime) > BOUNCE_TIME) {
    suspRequest = true;
    suspenseTime = currentMillis;
  }
}
void state7() {
  unsigned long trafficMillis = millis();
  unsigned long pedMillis = trafficMillis;
  digitalWrite(AMBER_TRAFFIC, HIGH);
  digitalWrite(RED_TRAFFIC, LOW);
  digitalWrite(CROSS, HIGH);
  digitalWrite(DONT_CROSS, LOW);
  digitalWrite(GREEN_TRAFFIC, LOW);
  while(true) {
    if(suspRequest) { return;}
    unsigned long currentMillis = millis();
    if((unsigned long)(currentMillis - trafficMillis) >= HALF_SEC){
      digitalWrite(AMBER_TRAFFIC, digitalRead(AMBER_TRAFFIC) ^ 1);
      trafficMillis = currentMillis;
    }
    if((unsigned long)(currentMillis - pedMillis) >= THRD_SEC){
      digitalWrite(CROSS, digitalRead(CROSS) ^ 1);
      pedMillis = currentMillis;
    }
  }
}

Page 150

void loop() {
  for(int i = 0; i < 6; i++){
    if(suspRequest) {
      suspRequest = false;
      suspended = !suspended;
      if(suspended) {
        states[0] = state7;
        i = 0;
      } else {
        states[0] = state1;
        i = 1; // restart at pedestrian safe point
      }
    }
    states[i]();
  }
}