Extra inputs for Devo Tx's

// PPM Encoder Joystick to Futaba Trainer Port
// For use with Arduino Nano V3.0
// Ian Johnston 29/04/2010
// Version 1.1 
//Low cost way to add extra POT's to any radio that accepts PPM input for <$15
//using an arduino nano and a few POT's, visit DeviationTX.com for info. 
//POT's on A1 and A2, PPM output on D13
//PPM inout to tip of 3.5 stereo, this is the black wire on your Devo 7E


int AI_Pin_AEL = 1;    // channel one analog in
int AI_Pin_ELE = 2;    // channel two analog in
int AI_Pin_THR = 3;    // channel three analog in
int AI_Pin_RUD = 4;    // channel four analog in
int AI_Pin_TIpot = 5;  // channel five analon in
int AI_Raw_AEL;        // Ana In raw var - 0->1023
int AI_Raw_ELE;        // Ana In raw var - 0->1023
int AI_Raw_THR;        // Ana In raw var - 0->1023
int AI_Raw_RUD;        // Ana In raw var - 0->1023
int AI_Raw_TIpot;        // Ana In raw var - 0->1023
int AI_AEL;           // Ana In var - 0->1023 compensated
int AI_ELE;           // Ana In var - 0->1023 compensated
int AI_THR;           // Ana In var - 0->1023 compensated
int AI_RUD;           // Ana In var - 0->1023 compensated
int AI_TIpot;           // Ana In var - 0->1023 compensated
int Aeleron_uS = 750;     // Ana In Ch.0 uS var - Aeleron
int Elevator_uS = 750;    // Ana In Ch.1 uS var - Elevator
int Throttle_uS = 750;    // Ana In Ch.2 uS var - Throttle
int Rudder_uS = 750;      // Ana In Ch.3 uS var - Rudder
int TI_uS = 750;          // Ana In Ch.4 uS var - TI
int TIsw_uS = 750;        // Ana In Ch.4 uS var - TI Switch
 
int Fixed_uS = 300;       // PPM frame fixed LOW phase
int pulseMin = 750;          // pulse minimum width minus start in uS
int pulseMax = 1700;      // pulse maximum width in uS
 
float DualrateMultAel = 0.9; // Dual rate mult
float DualrateMultEle = 0.9; // Dual rate mult
float DualrateMultThr = 0.9; // Dual rate mult
float DualrateMultRud = 0.9; // Dual rate mult
float DualrateMultTI = 0.9; // Dual rate mult
int DualrateAdjAel = 0;   // Dual rate mid adjustment
int DualrateAdjEle = 0;      // Dual rate mid adjustment
int DualrateAdjThr = 0;      // Dual rate mid adjustment
int DualrateAdjRud = 0;      // Dual rate mid adjustment
int DualrateAdjTI = 0;      // Dual rate mid adjustment
 
int outPinPPM = 13;       // digital pin 13
int outPinTEST = 8;       // digital pin 8
int inPinD6 = 6;          // digital pin 6
int inPinD11 = 11;        // digital pin 11
 
ISR(TIMER1_COMPA_vect) {
ppmoutput(); // Jump to ppmoutput subroutine
}
 
void setup() {
 
// Serial.begin(9600) ; // Test
 
pinMode(outPinPPM, OUTPUT);   // sets the digital pin as output
pinMode(inPinD6, INPUT);      // sets the digital pin as input
digitalWrite(inPinD6, HIGH);  // turn on pull-up resistor
pinMode(inPinD11, INPUT);     // sets the digital pin as input
digitalWrite(inPinD11, HIGH); // turn on pull-up resistor
 
// Setup timer
TCCR1A = B00110001; // Compare register B used in mode '3'
TCCR1B = B00010010; // WGM13 and CS11 set to 1
TCCR1C = B00000000; // All set to 0
TIMSK1 = B00000010; // Interrupt on compare B
TIFR1  = B00000010; // Interrupt on compare B
OCR1A = 22000; // 22mS PPM output refresh
OCR1B = 1000;
 
}
 
void ppmoutput() { // PPM output sub
 
// test pulse - used to trigger scope
// digitalWrite(outPinTEST, LOW);
// delayMicroseconds(100);    // Hold
// digitalWrite(outPinTEST, HIGH);
 
// Channel 1 - Aeleron
digitalWrite(outPinPPM, LOW);
delayMicroseconds(Fixed_uS);    // Hold
digitalWrite(outPinPPM, HIGH);
delayMicroseconds(Aeleron_uS);  // Hold for Aeleron_uS microseconds     
 
// Channel 2 - Elevator
digitalWrite(outPinPPM, LOW);
delayMicroseconds(Fixed_uS);    // Hold
digitalWrite(outPinPPM, HIGH);
delayMicroseconds(Elevator_uS); // Hold for Elevator_uS microseconds     
 
// Channel 3 - Throttle
digitalWrite(outPinPPM, LOW);
delayMicroseconds(Fixed_uS);    // Hold
digitalWrite(outPinPPM, HIGH);
delayMicroseconds(Throttle_uS); // Hold for Throttle_uS microseconds     
 
// Channel 4 - Rudder
digitalWrite(outPinPPM, LOW);
delayMicroseconds(Fixed_uS);    // Hold
digitalWrite(outPinPPM, HIGH);
delayMicroseconds(Rudder_uS);   // Hold for Rudder_uS microseconds
 
// Channel 5 - TI Switch
digitalWrite(outPinPPM, LOW);
delayMicroseconds(Fixed_uS);    // Hold
digitalWrite(outPinPPM, HIGH);
delayMicroseconds(TIsw_uS);     // Hold for TIsw_uS microseconds       
 
// Channel 6 - TI pot
digitalWrite(outPinPPM, LOW);
delayMicroseconds(Fixed_uS);    // Hold
digitalWrite(outPinPPM, HIGH);
delayMicroseconds(TI_uS);       // Hold for TI_uS microseconds 
 
// Synchro pulse
digitalWrite(outPinPPM, LOW);
delayMicroseconds(Fixed_uS);    // Hold
digitalWrite(outPinPPM, HIGH);  // Start Synchro pulse
 
} 

void loop() { // Main loop
 
// Read analogue ports
AI_Raw_AEL = analogRead(AI_Pin_AEL);
AI_Raw_ELE = analogRead(AI_Pin_ELE);
AI_Raw_THR = analogRead(AI_Pin_THR);
AI_Raw_RUD = analogRead(AI_Pin_RUD);
AI_Raw_TIpot = analogRead(AI_Pin_TIpot);
 
// Compensate for discrepancy in pot inputs including centering offset.
// Also use this to invert inputs if necessary (swap x1 & y1)
// y=mx+c, x to y scales to x1 to y1
AI_AEL = map(AI_Raw_AEL, 0, 1023, 1200, 0) - 100; // Invert Aeleron pot and slight centre offset
AI_ELE = map(AI_Raw_ELE, 0, 1023, 1200, 0) - 120; // Invert Elevator pot and slight centre offset
AI_THR = map(AI_Raw_THR, 0, 1023, 0, 1023) + 0;  // Throttle
AI_RUD = map(AI_Raw_RUD, 0, 1023, 0, 1023) + 0;  // Rudder
AI_TIpot = map(AI_Raw_TIpot, 0, 1023, 1023, 0) + 0;  // Thermal Intelligence pot (TI)
 
// Map analogue inputs to PPM rates for each of the channels
Aeleron_uS = (AI_AEL * DualrateMultAel) + pulseMin + DualrateAdjAel;
Elevator_uS = (AI_ELE * DualrateMultEle) + pulseMin + DualrateAdjEle;
Throttle_uS = (AI_THR * DualrateMultThr) + pulseMin + DualrateAdjThr;
Rudder_uS = (AI_RUD * DualrateMultRud) + pulseMin + DualrateAdjRud;
TI_uS = (AI_TIpot * DualrateMultTI) + pulseMin + DualrateAdjTI;
 
// Check limits
if (Aeleron_uS <= 750) Aeleron_uS = 750;     // Min
if (Aeleron_uS >= 1700) Aeleron_uS = 1700;   // Max  
if (Elevator_uS <= 750) Elevator_uS = 750;   // Min
if (Elevator_uS >= 1700) Elevator_uS = 1700; // Max
if (Throttle_uS <= 750) Throttle_uS = 750;   // Min
if (Throttle_uS >= 1700) Throttle_uS = 1700; // Max
if (Rudder_uS <= 750) Rudder_uS = 750;       // Min
if (Rudder_uS >= 1700) Rudder_uS = 1700;     // Max  
if (TI_uS <= 750) TI_uS = 750;               // Min
if (TI_uS >= 1700) TI_uS = 1700;             // Max
 
if (digitalRead(inPinD6) == 0) { // Low rate
DualrateMultAel = 0.5;
DualrateMultEle = 0.5;
DualrateMultThr = 0.9;
DualrateMultRud = 0.7;
DualrateMultTI = 0.9;
DualrateAdjAel = 200;
DualrateAdjEle = 200;
DualrateAdjThr = 0;
DualrateAdjRud = 100;
DualrateAdjTI = 0;
}
 
if (digitalRead(inPinD6) == 1) { // Normal/high rate
DualrateMultAel = 0.9;
DualrateMultEle = 0.9;
DualrateMultThr = 0.9;
DualrateMultRud = 0.9;
DualrateMultTI = 0.9;
DualrateAdjAel = 0;
DualrateAdjEle = 0;
DualrateAdjThr = 0;
DualrateAdjRud = 0;
DualrateAdjTI = 0;
}
 
if (digitalRead(inPinD11) == 1) { // TI Switch   
TIsw_uS = 1700;
} else {
TIsw_uS = 750;
}
 
}