Initial commit

Author: tbultel

ppm2joystick.ino

@@ -0,0 +1,130 @@
+/*
+*
+* A very trivial PPM to USB Joystick converter, for teensy controllers
+* Time between falling edges is measured and converted to joystick axis.
+* Additionnally, the ranges are auto scaled.
+*
+*/
+
+// Maximum number of channels
+#define NB_PEAKS 15
+#define PPM_PIN  2
+
+unsigned long int before;
+
+typedef struct {
+  int val;
+  int min;
+  int max;
+} PEAK;
+
+PEAK peaks[NB_PEAKS];
+
+//specifing arrays and variables to store values
+
+void readPin()  {
+
+  static int i = 0;
+  unsigned int now = micros(); //store time value a when pin value is falling
+  unsigned diff = now-before;  //calculating time inbetween two peaks
+  before = now;        // 
+
+  if (diff > 6000) {
+    i=0;
+    return;
+  }
+
+  if (i++>NB_PEAKS)
+    i = 0;
+
+  peaks[i].val=diff;
+
+}
+
+unsigned int valToPos(int i) {
+  PEAK * pPeak = &peaks[i];
+  int range = pPeak->max-pPeak->min;
+
+  if (range == 0)
+    return 0;
+  
+  return ((pPeak->val-pPeak->min)*1024)/range;
+}
+
+bool valToButton(int i) {
+  int v = valToPos(i);
+  if (v > 512)
+    return true;
+  else
+    return false;
+}
+             
+void getPeaks(){
+
+  for (int i=0;i<NB_PEAKS;i++) {
+    PEAK * pPeak = &peaks[i];
+    if (pPeak->min>pPeak->val && pPeak->val != 0)
+      pPeak->min = pPeak->val;
+
+    if (pPeak->max < pPeak->val)
+      pPeak->max = pPeak->val;
+      
+ #ifdef DEBUG
+    Serial.print(x[i]);
+
+    Serial.print("(");
+    Serial.print(xMin[i]);
+    Serial.print(",");
+    Serial.print(xMax[i]);
+    Serial.print(")->");
+    Serial.print(valToPos(i));
+
+    Serial.print("\t");
+ #endif
+
+    
+  }
+#ifdef DEBUG
+  Serial.println("");
+#endif // DEBUG
+
+  Joystick.X(valToPos(1));
+  Joystick.Y(valToPos(2));
+  Joystick.Z(valToPos(3));
+  Joystick.Zrotate(valToPos(4));
+
+  Joystick.sliderLeft(valToPos(5));
+  Joystick.sliderRight(valToPos(6));
+
+  Joystick.button(1, valToButton(7));
+  Joystick.button(2, valToButton(8));
+  Joystick.button(3, valToButton(9));
+
+
+}     
+
+
+void setup()
+{
+#ifdef DEBUG
+  Serial.begin(9600);
+#endif // DEBUG  
+  pinMode(PPM_PIN, INPUT_PULLUP);
+  Joystick.useManualSend(true);
+  for (int i=0; i<NB_PEAKS;i++) {
+    PEAK * pPeak = &peaks[i];
+    pPeak->min=1000;
+    pPeak->max=2000;
+  }
+  
+  attachInterrupt(digitalPinToInterrupt(2), readPin , FALLING);
+}
+
+void loop()
+{
+  getPeaks();
+
+  Joystick.send_now();
+  
+  delay(20);  // do not print too fast!
+}