Create PotentiometerChange.ino

Author: tigoe

PotentiometerChange/PotentiometerChange.ino

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+/*
+  Stable Potentiometer change sensor
+
+  Sometimes you need a continuously changing analog sensor
+  (like a potentiometer) to send only when it stops changing.
+  One way to do this is to only send periodically, and only
+  if the sensor has changed significantly. This sketch shows
+  how that can work.
+
+  Circuit:
+  - potentiometer attached to pin A0
+
+  created 23 Feb 2020
+  by Tom Igoe
+*/
+
+// noise threshold. any change less than this is noise:
+int noise = 5;
+// previous reading:
+int lastReading = 0;
+// send interval, in ms:
+int sendInterval = 1000;
+// last time you sent a reading, in ms:
+long lastSendTime = 0;
+
+void setup() {
+  Serial.begin(9600);
+}
+
+void loop() {
+  // if the send interval has passed:
+  if (millis() - lastSendTime > sendInterval) {
+    // read the sensor:
+    int sensor = analogRead(A0);
+    // map to a different range if needed:
+    //    sensor = map(sensor, 0, 1023, 0, 255);
+    // if the difference between current and last > noise:
+    if (abs(sensor - lastReading) > noise) {
+      // send it:
+      Serial.println(sensor);
+    }
+    // save current reading for comparison next time:
+    lastReading = sensor;
+    // take a timestamp of when you sent:
+    lastSendTime = millis();
+  }
+}