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/*
Conditionals - while statement
This example demonstrates the use of while() statements.
While the built-in button is pressed, the sketch runs the
calibration routine. The sensor readings during the while loop
define the minimum and maximum of expected values from the photo
resistor.
This is a variation of the Analog > Calibration example.
The circuit:
* Photo resistor connected from +3.3V to pin 15
* 10K resistor connected from ground to pin 15
* LED connected from digital pin 9 to ground through 220 ohm resistor
* 10K resistor attached from pin 2 to ground
created 17 Jan 2009
modified 25 Jun 2009
by Tom Igoe
modified for Maple 13 February 2011
by LeafLabs
http://leaflabs.com/docs/lang/cpp/while.html
*/
// These constants won't change:
const int sensorPin = 2; // pin that the sensor is attached to
const int ledPin = 9; // pin that the LED is attached to
// These variables will change:
int sensorMin = 4095; // minimum sensor value
int sensorMax = 0; // maximum sensor value
int sensorValue = 0; // the sensor value
void setup() {
// set the LED pins as outputs and the switch pin as input:
pinMode(ledPin, OUTPUT); // LED on pin 9
pinMode(BOARD_LED_PIN, OUTPUT); // Built-in LED
pinMode(BOARD_BUTTON_PIN, INPUT); // Built-in button
}
void loop() {
// while the button is pressed, take calibration readings:
while (digitalRead(BOARD_BUTTON_PIN) == HIGH) {
// You could also use this:
//while (isButtonPressed()) {
calibrate();
}
// signal the end of the calibration period
digitalWrite(BOARD_LED_PIN, LOW);
// read the sensor:
sensorValue = analogRead(sensorPin);
// apply the calibration to the sensor reading
sensorValue = map(sensorValue, sensorMin, sensorMax, 0, 65535);
// in case the sensor value is outside the range seen during calibration
sensorValue = constrain(sensorValue, 0, 65535);
// fade the LED using the calibrated value:
pwmWrite(ledPin, sensorValue);
}
void calibrate() {
// turn on the built-in LED to indicate that calibration is happening:
digitalWrite(BOARD_LED_PIN, HIGH);
// read the sensor:
sensorValue = analogRead(sensorPin);
// record the maximum sensor value
if (sensorValue > sensorMax) {
sensorMax = sensorValue;
}
// record the minimum sensor value
if (sensorValue < sensorMin) {
sensorMin = sensorValue;
}
}
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