Hi all, i wired a co2 sensor to an arduino board following this wiring
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I have a doubt: is my map function (posted below) correct? I mean, following the specs give on its datasheet (CO2 Sensor) we should have an output of 30-50 mv (which is what i get) corresponding to 350 - 10000 ppm. Is my interpretation correct? Or should i change the way i'm reading values to get the correct ones? Thanks in advance
#define R 11 //led RED
#define L 12 //led YELLOW 1
#define G 13 //led GREEN
#define K 10 //led YELLOW 2
#define PIN 0 //analog PIN wired to co2 sensor
#define SOGLIA 1000 // 1000ppm OK value
unsigned int lettura = 0; //actual read value
unsigned int letturaOld = 0; //old read value
unsigned long time;
void reading(){ //led blinking while reading
digitalWrite(R, LOW);
digitalWrite(K, LOW);
digitalWrite(G, LOW);
int cont = 0;
while (cont < 15){
digitalWrite(L, HIGH);
delay(500);
digitalWrite(L, LOW);
delay(500);
cont++;
}
}
void victory(){ //led blinking when SOGLIA read
digitalWrite(R, LOW);
digitalWrite(G, HIGH);
int cont = 0;
while (cont < 15){
digitalWrite(L, HIGH);
digitalWrite(K, LOW);
delay(500);
digitalWrite(L, LOW);
digitalWrite(K, HIGH);
delay(500);
cont++;
}
}
void rightWay(){ //led blinking when lettura < letturaOld
digitalWrite(R, LOW);
digitalWrite(K, LOW);
digitalWrite(G, HIGH);
int cont = 0;
while (cont < 15){
digitalWrite(L, HIGH);
delay(500);
digitalWrite(L, LOW);
delay(500);
cont++;
}
}
void wrongWay(){ //led blinking when lettura > letturaOld
digitalWrite(R, HIGH);
digitalWrite(K, LOW);
digitalWrite(G, LOW);
int cont = 0;
while (cont < 15){
digitalWrite(L, HIGH);
delay(500);
digitalWrite(L, LOW);
delay(500);
cont++;
}
}
void setup(){
pinMode(PIN, INPUT);
pinMode(R, OUTPUT);
pinMode(L, OUTPUT);
pinMode(G, OUTPUT);
pinMode(K, OUTPUT);
Serial.begin(9600);
}
void loop(){
time = millis();
if ( time <= 300000) { //5 minutes heating time
digitalWrite(R, HIGH);
digitalWrite(L, HIGH);
digitalWrite(K, HIGH);
digitalWrite(G, HIGH);
letturaOld = analogRead(PIN); //keeps on reading
letturaOld = map(letturaOld,0,1023,350,10000);
Serial.print(time/1000);
Serial.println(" seconds elapsed. Heating in progress...");
delay(10000);
}
else if ( time > 300000 && time < 305000 ) { // leds off
digitalWrite(R, LOW);
digitalWrite(L, LOW);
digitalWrite(K, LOW);
digitalWrite(G, LOW);
}
else{
//blinking YELLOW led while reading
reading();
delay(1500);
lettura = analogRead(PIN);
lettura = map(lettura,0,1023,350,10000);
Serial.print("Vecchia lettura: "); //old reading
Serial.print(letturaOld);
Serial.print(" | Nuova lettura: "); //new reading
Serial.println(lettura);
if ( lettura < SOGLIA ){
victory(); //we're done! ding ding ding!
delay(1500);
}
else{
if (lettura < letturaOld)
rightWay();
else
wrongWay();
}
letturaOld = lettura;
lettura = 0;
delay(1500);
}
}
got it 