Proximity (Ultrasonic)

const int TRIG_PIN = 12; // Pins
const int ECHO_PIN = 11;const unsigned int MAX_DIST = 23200; // Anything over 400 cm (23200 us pulse) is "out of range"

void setup() { pinMode(TRIG_PIN, OUTPUT); digitalWrite(TRIG_PIN, LOW); Serial.begin(9600);}

void loop() {
unsigned long t1, t2, pulse_width; float cmValue, inchesValue;
digitalWrite(TRIG_PIN, HIGH); // Hold the trigger pin high for at least 10 us delayMicroseconds(10); digitalWrite(TRIG_PIN, LOW);
while ( digitalRead(ECHO_PIN) == 0 ); // Wait for pulse on echo pin t1 = micros(); while ( digitalRead(ECHO_PIN) == 1); //end of echo t2 = micros(); pulse_width = t2 - t1; //calculate time between send pulse and returned pulse cmValue = pulse_width / 58.0; //convert time into cm inchesValue = pulse_width / 148.0; //convert time into inches
if ( pulse_width > MAX_DIST ) { Serial.println("Out of range"); } else { Serial.print(cmValue); //print distance in cm Serial.print(" cm \t"); Serial.print(inchesValue); //print distance in inches Serial.println(" in"); } delay(60);}

ProximitySensor.mp4

Challenge: Use the proximity sensor in combination with the RGB LED. As you move an object towards the sensor, use the LED's to give indication to your distance. If you're far display green, closer yellow, and very close red. And perhaps if you're too close flashing red.