Assignment: Input / Output Coincidence Lab Assignment
Collaborators:
Description
My project tries to replicate the actions used in lighting and blowing out a candle with a photocell, an LED, and a Piezo speaker. To light the candle, a "match" (in this case, a flashlight made to look like a match), is shined on the candle holder. This turns an LED within the candle holder on. I adapted the Knock code in order to get input from the Piezo speaker. I set the Piezo speaker is set to register very low levels of vibration, so a forceful blow turns the LED off (i.e. blowing out the candle).
Components Used
- Light Emitting Diode (LED)--red
- 220 ohm resistor
- 10k resistor
- 1M resistor
- Arduino board
- Bread board
- Wires
- Photocell
- Piezo speaker
- Flashlight
- Candle holder
- Electrical tape
- Coffee filter (for LED diffusion)
Arduino Code
/* Piezo candle
* A photocell activates an LED when enough light is provided (by a "match").
* A piezo registers the vibration of a forceful blow to turn the LED off.
*/
const int ledPin = 13; // led connected to digital pin 13
const int blowSensor = 0; // the Piezo is connected to analog pin 0
const int threshold = 5; // threshold value to decide when vibration is detected
const int lightSensor = 2; // the photocell is connected to analog pin 2
int sensorReading = 0; // variable to store the value read from the sensor pin
int val = 0; //variable to store the value coming from the photocell
void setup() {
pinMode(ledPin, OUTPUT); // declare the ledPin as as OUTPUT
}
void loop() {
// read the sensor and store it in the variable sensorReading:
val = analogRead(lightSensor); //read the value from the photocell
if (val > 400) {
// update the LED to be on
digitalWrite(ledPin, HIGH);
}
sensorReading = analogRead(blowSensor);
// if the sensor reading is greater than the threshold:
if (sensorReading >= threshold) {
// update the LED pin to be off
digitalWrite(ledPin, LOW);
}
delay(100); // delay
}
Photos
Set up
Candle holder with Piezo, LED, and photocell
Flashlight "match"
Lit LED
