83 lines
2.4 KiB
C++
83 lines
2.4 KiB
C++
/*
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Conditionals - while statement
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This example demonstrates the use of while() statements.
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While the built-in button is pressed, the sketch runs the
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calibration routine. The sensor readings during the while loop
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define the minimum and maximum of expected values from the photo
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resistor.
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This is a variation of the Analog > Calibration example.
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The circuit:
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* Photo resistor connected from +3.3V to pin 15
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* 10K resistor connected from ground to pin 15
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* LED connected from digital pin 9 to ground through 220 ohm resistor
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* 10K resistor attached from pin 2 to ground
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created 17 Jan 2009
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modified 25 Jun 2009
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by Tom Igoe
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modified for Maple 13 February 2011
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by LeafLabs
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http://leaflabs.com/docs/lang/cpp/while.html
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*/
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// These constants won't change:
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const int sensorPin = 2; // pin that the sensor is attached to
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const int ledPin = 9; // pin that the LED is attached to
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// These variables will change:
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int sensorMin = 4095; // minimum sensor value
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int sensorMax = 0; // maximum sensor value
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int sensorValue = 0; // the sensor value
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void setup() {
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// set the LED pins as outputs and the switch pin as input:
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pinMode(ledPin, OUTPUT); // LED on pin 9
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pinMode(33, OUTPUT); // Built-in LED
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pinMode(BOARD_BUTTON_PIN, INPUT); // Built-in button
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}
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void loop() {
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// while the button is pressed, take calibration readings:
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while (digitalRead(BOARD_BUTTON_PIN) == HIGH) {
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// You could also use this:
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//while (isButtonPressed()) {
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calibrate();
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}
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// signal the end of the calibration period
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digitalWrite(33, LOW);
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// read the sensor:
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sensorValue = analogRead(sensorPin);
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// apply the calibration to the sensor reading
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sensorValue = map(sensorValue, sensorMin, sensorMax, 0, 65535);
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// in case the sensor value is outside the range seen during calibration
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sensorValue = constrain(sensorValue, 0, 65535);
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// fade the LED using the calibrated value:
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pwmWrite(ledPin, sensorValue);
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}
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void calibrate() {
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// turn on the built-in LED to indicate that calibration is happening:
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digitalWrite(33, HIGH);
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// read the sensor:
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sensorValue = analogRead(sensorPin);
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// record the maximum sensor value
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if (sensorValue > sensorMax) {
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sensorMax = sensorValue;
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}
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// record the minimum sensor value
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if (sensorValue < sensorMin) {
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sensorMin = sensorValue;
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}
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}
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