Crit1 Development: Experiment with Fan Motor and Light Sensor TEMT6000

With the TEMT6000 light sensor, I can turn on a motor based on input to the light sensor, similar to the one I had with the DHT-22.

With the TEMT6000, I used an analog write (instead of the digital write with the DHT-22) and the data arrives in float form. Several lines of code convert the reading into a percent. Data smoothing and millis () set up are the same as previous DHT-22 code.

#define lightPin A0 //Ambient light sensor reading 

//data smoothing
const int numReadings = 5;
float ligReadings [numReadings];
int ligReadIndex = 0;
float ligTotal = 0;
float ligAverage = 0;
int inputPin = lightPin; //put sensor pin here
//detecting sensor change
int last;
//response to sensor change

//for fan and motor
int speedPin = 5;
int dir1 = 4;
int dir2 = 3;
int mSpeed = 0;
unsigned long lastReadTime = 0;

void setup() {
  // put your setup code here, to run once:
  //pins for fan and motot
  pinMode(speedPin, OUTPUT);
  pinMode(dir1, OUTPUT);
  pinMode(dir2, OUTPUT);
  pinMode(lightPin, INPUT);

  for (int thisReading = 0; thisReading < numReadings; thisReading++) {
    ligReadings[thisReading] = 0;
  }
  Serial.begin(9600);
  lastReadTime = millis();
}

void loop() {
  //delay(1000);

  if ((millis() - lastReadTime) >= 5000UL) {
    Serial.println(lastReadTime);
    Serial.println(millis());
    lastReadTime = millis();
    //light sensor read
    float light = analogRead(lightPin);
    float light_ratio = light / 1023.0;
    float light_percent = light_ratio * 100;

    ligTotal = ligTotal - ligReadings[ligReadIndex];
    ligReadings[ligReadIndex] = light_percent;
    ligTotal = ligTotal + ligReadings [ligReadIndex];
    ligReadIndex = ligReadIndex + 1;
    if (ligReadIndex >= numReadings) {
      ligReadIndex = 0;
    }
    ligAverage = ligTotal / numReadings;
    Serial.println(light_percent);
    Serial.println(ligAverage);

  }



  if (ligAverage > 25)
  {
    digitalWrite(dir1, HIGH);
    digitalWrite(dir2, LOW);
    analogWrite(speedPin, 225);
  }else
  {
    digitalWrite(dir1,HIGH);
    digitalWrite(dir2,LOW);
    analogWrite(speedPin, 0);
  }
}

Next, I plan to use the sensor to turn another motor (the stepper motor, which I think is a better fit for turning the plant turntable).