[chronojump] Arduino code for races encoder

[Xavier Padullés <xpadulles src gnome org>]

commit 8e3744630ba95e49c887513c7c3cf9cf1303ed43
Author: Xavier Padullés <x padulles gmail com>
Date:   Wed Apr 11 13:05:21 2018 +0200

    Arduino code for races encoder

 arduino/raceEncoder/raceEncoder.ino |   95 +++++++++++++++++++++++++++++++++++
 1 files changed, 95 insertions(+), 0 deletions(-)
---
diff --git a/arduino/raceEncoder/raceEncoder.ino b/arduino/raceEncoder/raceEncoder.ino
new file mode 100644
index 0000000..b0228b9
--- /dev/null
+++ b/arduino/raceEncoder/raceEncoder.ino
@@ -0,0 +1,95 @@
+
+int val;
+int encoderPinA = 2;
+int encoderPinB = 3;
+volatile int encoderDisplacement = 0;
+volatile unsigned long changingTime;
+unsigned long elapsedTime;
+unsigned long lastTime;
+
+void setup() {
+  pinMode (encoderPinA, INPUT);
+  pinMode (encoderPinB, INPUT);
+  Serial.begin (115200);
+
+  //Using the rising flank of the A photocell we have a 200 PPR.
+  attachInterrupt(digitalPinToInterrupt(encoderPinA), changingA, RISING);
+
+  //Using the CHANGE with both photocells WE CAN HAVE 800 PPR
+  //attachInterrupt(digitalPinToInterrupt(encoderPinB), changingB, CHANGE);
+}
+
+void loop() {
+  //With a diameter is of 160mm, each pulse is 2.513274mm. 4 pulses equals 1.00531cm
+  if ( abs(encoderDisplacement) >= 4 ) {
+
+    int lastEncoderDisplacement = encoderDisplacement; //Assigned to another variable for in the case that 
encoder displacement changes before printing it
+    unsigned long Time = changingTime;
+    encoderDisplacement = 0;
+
+    //Managing the timer overflow
+    if (Time > lastTime)      //No overflow
+    {
+      elapsedTime = Time - lastTime;
+    } else  if (Time <= lastTime)  //Overflow
+    {
+      elapsedTime = (4294967295 - lastTime) + Time; //Time from the last measure to the overflow event plus 
the changingTime
+    }
+
+    Serial.print(lastEncoderDisplacement);
+    Serial.print(";");
+    Serial.println(elapsedTime);
+    lastTime = changingTime;
+  }
+  delayMicroseconds(100);
+}
+
+void changingA() {
+  changingTime = micros();
+  if (digitalRead(encoderPinB) == HIGH) {
+    encoderDisplacement--;
+  } else {
+    encoderDisplacement++;
+  }
+}
+
+/***********************************************************************
+   If we need more precission we can use both flanks of both photocells
+ * *********************************************************************
+
+  void changingA() {
+  changingTime = micros();
+  if (digitalRead(encoderPinA) == HIGH) {
+    if (digitalRead(encoderPinB) == HIGH) {
+      encoderDisplacement--;
+    } else {
+      encoderDisplacement++;
+    }
+  } else {
+    if (digitalRead(encoderPinB) == HIGH) {
+      encoderDisplacement++;
+    } else {
+      encoderDisplacement--;
+    }
+  }
+  }
+
+  void changingB() {
+  changingTime = micros();
+  if (digitalRead(encoderPinB) == HIGH) {
+    if (digitalRead(encoderPinA) == HIGH) {
+      encoderDisplacement++;
+    } else {
+      encoderDisplacement--;
+    }
+  } else {
+    if (digitalRead(encoderPinA) == HIGH) {
+      encoderDisplacement--;
+    } else {
+      encoderDisplacement++;
+    }
+  }
+  }
+
+*/
+