interfacing alcohol sensor with the led

Programmed the Arduino to have the alcohol sensor play with the LED display.

I had the display show either "open" or "lock" depending on the alcohol sensor level.

Here is the result:

Notice that this has a very notable flaw with respect to its potential use as a "breathalyzer lock": it stays "open" as long as there is alcohol present, which only then "lock"s. This means that currently, if you leave it alone (no breathing into it), it will keep the device unlocked.

This is something I will have to resolve.


code used for this:

int del = 5000;
int gasPin = 0;
int value = 0;
int lastValue = 0;

void setup(){
//  Serial.begin(9600);
  pinMode(12, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(7, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(2, OUTPUT);
  pinMode(1, OUTPUT);

}

void loop(){
  lastValue = value;
  value = analogRead(gasPin)/2;
//  Serial.print("Sensor:");
//  Serial.println(value);

  if(value - lastValue > 10 || value > 400) {
    lockPrint();
  } else {
    openPrint();
  }

}

void lockPrint() {
  pickDigit(1);
  digitalWrite(8, HIGH);
  digitalWrite(1, HIGH); // A
  digitalWrite(2, HIGH); // B
  digitalWrite(3, HIGH); // C
  digitalWrite(4, LOW); // D
  digitalWrite(5, LOW); // E
  digitalWrite(6, LOW); // F
  digitalWrite(7, HIGH); // G
  delayMicroseconds(del);
  pickDigit(2);
  digitalWrite(8, HIGH);
  digitalWrite(1, LOW); // A
  digitalWrite(2, LOW); // B
  digitalWrite(3, LOW); // C
  digitalWrite(4, LOW); // D
  digitalWrite(5, LOW); // E
  digitalWrite(6, LOW); // F
  digitalWrite(7, HIGH); // G
  delayMicroseconds(del);
  pickDigit(3);
  digitalWrite(8, HIGH);
  digitalWrite(1, LOW); // A
  digitalWrite(2, HIGH); // B
  digitalWrite(3, HIGH); // C
  digitalWrite(4, LOW); // D
  digitalWrite(5, LOW); // E
  digitalWrite(6, LOW); // F
  digitalWrite(7, HIGH); // G
  delayMicroseconds(del);
  pickDigit(4);
  digitalWrite(8, HIGH);
  digitalWrite(1, LOW); // A
  digitalWrite(2, HIGH); // B
  digitalWrite(3, LOW); // C
  digitalWrite(4, HIGH); // D
  digitalWrite(5, LOW); // E
  digitalWrite(6, LOW); // F
  digitalWrite(7, LOW); // G
  delayMicroseconds(del);
}

void openPrint() {
  pickDigit(1);
  digitalWrite(8, HIGH);
  digitalWrite(1, LOW); // A
  digitalWrite(2, LOW); // B
  digitalWrite(3, LOW); // C
  digitalWrite(4, LOW); // D
  digitalWrite(5, LOW); // E
  digitalWrite(6, LOW); // F
  digitalWrite(7, HIGH); // G
  delayMicroseconds(del);
  pickDigit(2);
  digitalWrite(8, HIGH);
  digitalWrite(1, LOW); // A
  digitalWrite(2, LOW); // B
  digitalWrite(3, HIGH); // C
  digitalWrite(4, HIGH); // D
  digitalWrite(5, LOW); // E
  digitalWrite(6, LOW); // F
  digitalWrite(7, LOW); // G
  delayMicroseconds(del);
  pickDigit(3);
  digitalWrite(8, HIGH);
  digitalWrite(1, LOW); // A
  digitalWrite(2, HIGH); // B
  digitalWrite(3, HIGH); // C
  digitalWrite(4, LOW); // D
  digitalWrite(5, LOW); // E
  digitalWrite(6, LOW); // F
  digitalWrite(7, LOW); // G
  delayMicroseconds(del);
  pickDigit(4);
  digitalWrite(8, HIGH);
  digitalWrite(1, LOW); // A
  digitalWrite(2, LOW); // B
  digitalWrite(3, LOW); // C
  digitalWrite(4, HIGH); // D
  digitalWrite(5, LOW); // E
  digitalWrite(6, LOW); // F
  digitalWrite(7, HIGH); // G
  delayMicroseconds(del);
}

void pickDigit(int x){
  digitalWrite(12, LOW); // dig 1
  digitalWrite( 11, LOW); // dig 2
  digitalWrite(10, LOW); // dig 3
  digitalWrite( 9, LOW); // dig 4

  switch(x){
    case 1: digitalWrite(9, HIGH); break;
    case 2: digitalWrite(10, HIGH); break;
    case 3: digitalWrite(11, HIGH); break;
    case 4: digitalWrite(12, HIGH); break;  
  }
}