Adding a calibration example and moving knock into the sensors folder.

build/shared/dist/examples/Analog/Calibration/Calibration.pde

@@ -0,0 +1,49 @@
+/*
+ * Calibration
+ *
+ * Demonstrates one techinque for calibrating sensor input.  The
+ * sensor readings during the first five seconds of the sketch
+ * execution define the minimum and maximum of expected values.
+ */
+
+int sensorPin = 2;
+int ledPin = 9;
+
+int val = 0;
+int sensorMin = 1023, sensorMax = 0;
+
+void setup() {
+  // signal the start of the calibration period
+  pinMode(13, OUTPUT);
+  digitalWrite(13, HIGH);
+  
+  // calibrate during the first five seconds 
+  while (millis() < 5000) {
+    val = analogRead(sensorPin);
+    
+    // record the maximum sensor value
+    if (val > sensorMax) {
+      sensorMax = val;
+    }
+    
+    // record the minimum sensor value
+    if (val < sensorMin) {
+      sensorMin = val;
+    }
+  }
+  
+  // signal the end of the calibration period
+  digitalWrite(13, LOW);
+}
+
+void loop() {
+  val = analogRead(sensorPin);
+  
+  // apply the calibration to the sensor reading
+  val = map(val, sensorMin, sensorMax, 0, 255);
+  
+  // in case the sensor value is outside the range seen during calibration
+  val = constrain(val, 0, 255);
+  
+  analogWrite(ledPin, val);
+}

build/shared/dist/examples/Analog/Knock/Knock.pde

@@ -1,34 +0,0 @@
-/* Knock Sensor
- * by DojoDave <http://www.0j0.org>
- *
- * Program using a Piezo element as if it was a knock sensor.
- *
- * We have to basically listen to an analog pin and detect 
- * if the signal goes over a certain threshold. It writes
- * "knock" to the serial port if the Threshold is crossed,
- * and toggles the LED on pin 13.
- *
- * http://www.arduino.cc/en/Tutorial/Knock
- */
-
-int ledPin = 13;      // led connected to control pin 13
-int knockSensor = 0;  // the knock sensor will be plugged at analog pin 0
-byte val = 0;         // variable to store the value read from the sensor pin
-int statePin = LOW;   // variable used to store the last LED status, to toggle the light
-int THRESHOLD = 100;  // threshold value to decide when the detected sound is a knock or not
-
-void setup() {
- pinMode(ledPin, OUTPUT); // declare the ledPin as as OUTPUT
- Serial.begin(9600);       // use the serial port
-}
-
-void loop() {
-  val = analogRead(knockSensor);    // read the sensor and store it in the variable "val"
-  if (val >= THRESHOLD) {
-    statePin = !statePin;           // toggle the status of the ledPin (this trick doesn't use time cycles)
-    digitalWrite(ledPin, statePin); // turn the led on or off
-    Serial.println("Knock!");          // send the string "Knock!" back to the computer, followed by newline
-  }
-  delay(100);  // we have to make a delay to avoid overloading the serial port
-}
-