I’m trying to get 2 Arduino megas to communicate via XBee series 1. I know that they’re actually transmitting and receiving data (I checked using X-CTU), but I’m not getting anything when I try to print the battery voltage. It just displays zero the whole time (again, I do know that the bytes are being received). Below is the code I have for the receiver in the pair of XBees, and this is where I’m having the issue.
#include <LiquidCrystal.h> //library for the LCD
byte incoming; //incoming serial byte
//variables to store input values from joysticks from the remote
byte X; //Joystick horizontal movement
byte Y; //Joystick vertical movement
//variables to store analog input values
int Fresist_L1 = 100; //Force resistor #1 in left leg; analog pin 0
int Fresist_L2 = 0; //Force resistor #2 in left leg; analog pin 1
int Fresist_L3 = 0; //Force resistor #3 in left leg; analog pin 2
int Fresist_R1 = 145; //Force resistor #1 in right leg; analog pin 3
int Fresist_R2 = 0; //Force resistor #2 in right leg; analog pin 4
int Fresist_R3 = 0; //Force resistor #3 in right leg; analog pin 5
//variables to store digital input values
int lcdSw; //switch to cycle lcd screens
int PresSw; //pump status?
//Internal variables
int CenterSw; //switch used in conjuction with joysticks to center legs
int BloodSw; //switch to control the "blood pump"
byte connection; //show if MATT is connected
int screen = 0; //variable to store screen selection of LCD
long minutesD = 1; //Set minutes til death after testing
long secondsD = 2; //Set seconds til death after testing
int Eminutes, Eseconds; //Elapsed time
int minsD, secsD; //Time until death
int pumpStartTime=0; //time the pump is turned on
int count = 0;
int Dmins = 1; //minutes until MATT dies
int Dsecs = 2; //seconds until MATT dies
long totalSeconds;
int serial_count = 0;
static unsigned long TotalFlowL = 0; //freq of L flow sensor
static unsigned long TotalFlowR = 0; //freq of R flow sensor
int intRemBatVolt, decRemBatVolt, RemBatVolt;
//Digital pin assignments
int Hservo = 4; //PWM
int Vservo = 5; //PWM
int BldPum = 25;
int LCD_RS = 26;
int LCD_EN = 27;
int LCD_D4 = 28;
int LCD_D5 = 29;
int LCD_D6 = 30;
int LCD_D7 = 31;
int LCD_Sw = 32;
int Pres_Sw = 33;
//Analog input pin assignments
int FSR_L1 = 0;
int FSR_L2 = 1;
int FSR_L3 = 2;
int FSR_R1 = 3;
int FSR_R2 = 4;
int FSR_R3 = 5;
int BatVol = 6;
//LiquidCrystal lcd( RS, Enable, D4, D5, D6, D7 )
LiquidCrystal lcd(LCD_RS, LCD_EN, LCD_D4, LCD_D5, LCD_D6, LCD_D7);
void setup() {
// initialize serial communications at 9600 bps:
Serial.begin(9600);
// setup pins as input and output
pinMode(Hservo, OUTPUT); //Horiz PWM control of leg
pinMode(Vservo, OUTPUT); //Vert PWM control of leg
pinMode(Pres_Sw, INPUT); //Pressure switch sensor
pinMode(BldPum, OUTPUT); //Blood pump control relay
pinMode(LCD_RS, OUTPUT); //LCD RS pin 4
pinMode(LCD_EN, OUTPUT); //LCD Enable pin 6
pinMode(LCD_D4, OUTPUT); //LCD D4 pin 11
pinMode(LCD_D5, OUTPUT); //LCD D5 pin 12
pinMode(LCD_D6, OUTPUT); //LCD D6 pin 13
pinMode(LCD_D7, OUTPUT); //LCD D7 pin 14
lcd.begin(20,4);
lcd.clear();
Serial.flush();
}
void loop() {
screen = LCD(screen);
//Handshake
while (count == 0) {
Serial.print(255, BYTE);
Serial.print(1, BYTE);
incoming = Serial.read();
if (int(incoming) == 255) {
connection = Serial.read();
if (int(connection) == 1) {
Serial.flush();
count = 10;
}
}
}
//Set pump start time
if (Serial.read() == 252) {
BloodSw = Serial.read();
if ((BloodSw == HIGH) && (connection == 1)) {
if (count == 10) {
pumpStartTime = millis();
count = 50;
}
}
}
//Used to calculate frequency of flow sensors
if ((millis() % 1000) == 0) {
if (TotalFlowL == 0) {
LzeroCount++;
}
else if (TotalFlowL > 0) {
LzeroCount--;
}
if (TotalFlowR == 0) {
RzeroCount++;
}
else if (TotalFlowR > 0) {
RzeroCount--;
}
TotalFlowL = 0;
TotalFlowR = 0;
}
//read incoming serial data and determine which SYNC
if (Serial.available() > 0) {
incoming = Serial.read();
if (Serial.available() > 0) {
//SYNC with remote / handshake
if (int(incoming) == 255) {
connection = Serial.read();
}
//Left joystick/leg, horizontal direction
if (int(incoming) == 254) {
X = Serial.read();
X = map(int(X), 0, 245, 0, 1023);
analogWrite(Hservo, int(X));
}
//Joystick/leg, vertial direction
if (int(incoming) == 253) {
Y = Serial.read();
Y = map(int(Y), 0, 245, 0, 1023);
analogWrite(Vservo, int(Y));
}
//Turn blood pump on/off
if (int(incoming) == 252) {
BloodSw = Serial.read();
if (int(BloodSw) == 1) {
digitalWrite(BldPum, HIGH);
}
else if (int(BloodSw) == 0) {
digitalWrite(BldPum, LOW);
}
}
//AutoMATT
if (int(incoming) == 251) {
AutoMATT = Serial.read();
}
//Remote's Battery Voltage
if (int(incoming) == 250) {
RemBatVolt = int(Serial.read());
RemBatVolt = map(RemBatVolt, 0, 245, 0, 1023);
intRemBatVolt = RemBatVolt / 83;
decRemBatVolt = RemBatVolt % 83;
}
}
}
Fresist_L = average(Fresist_L1, Fresist_L2, Fresist_L3);
Fresist_R = average(Fresist_R1, Fresist_R2, Fresist_R3);
if (serial_count > 45) {
//Sending data
Serial.print(255, BYTE); //Connected?
Serial.print(1, BYTE);
Serial.print(254, BYTE);
Serial.print(BloodSw, BYTE); //Blood pumping?
Serial.print(253, BYTE);
Serial.print(Lbloodflow, BYTE); //Left leg bleeding?
Serial.print(252, BYTE);
Serial.print(Rbloodflow, BYTE); //Right leg bleeding?
Serial.print(251, BYTE);
Serial.print(Vbloodflow, BYTE); //Vein bleeding?
//Need to know how many force sensors will be used to determine
//how many variables/SYNCs are needed
Serial.print(250, BYTE);
Serial.print(Fresist_L, BYTE); //max force in L leg
Serial.print(249, BYTE);
Serial.print(Fresist_R, BYTE); //max force in R leg
serial_count = 0;
}
serial_count++;
}
int average(int a, int b, int c) {
int avg = a + b + c;
avg = avg/3;
return avg;
}
int LCD(int S) {
lcdSw = digitalRead(LCD_Sw);
//Splash Screen
if (S == 0) {
lcd.setCursor(3,2);
if (connection == 1) {
lcd.print(" Connected ");
}
else if (connection == 0) {
lcd.print("Not Connected");
}
if (connection == 1) {
lcd.clear();
return 1;
}
else {
return 0;
}
}
//Battery Screen
if (S == 1) {
delay(60);
lcd.setCursor(0,0);
lcd.print("Remote Batt.: ");
lcd.print(intRemBatVolt,DEC);
lcd.print(".");
lcd.print(decRemBatVolt,DEC);
lcd.print("V");
lcd.setCursor(0,1);
if (lcdSw == HIGH) {
delay(150);
lcd.clear();
return 2;
}
else {
return 1;
}
}
//Miscellaneous Screen
if (S == 2) {
delay(60);
//Display length of exercise
LCD_printTime(Dmins, Dsecs);
if (lcdSw == HIGH) {
delay(150); //allow time for button to be depressed
lcd.clear();
return 1;
}
else {
return 2;
}
}
}
void LCD_printTime(int Dmins, int Dsecs) {
totalSeconds = (millis() - pumpStartTime)/1000;
long Eminutes = floor(totalSeconds/60);
long Eseconds = floor(totalSeconds - (Eminutes*60));
//print values to lcd
lcd.setCursor(0,0);
lcd.print("Time Elapsed: ");
lcd.print(Eminutes);
lcd.print(":");
if (Eseconds < 10) {
lcd.print(0);
}
lcd.print(Eseconds);
//Time until death
long totalSeconds_Death = (Dmins*60) + Dsecs - totalSeconds;
lcd.setCursor(0,1);
lcd.print("Dead In: ");
int Dminutes = floor(totalSeconds_Death/60);
int Dseconds = floor(totalSeconds_Death - (Dminutes*60));
if ((Dminutes < 1) && (Dseconds < 0)) {
lcd.print("-");
totalSeconds_Death = (-1)*totalSeconds_Death;
Dminutes = floor(totalSeconds_Death/60);
Dseconds = floor(totalSeconds_Death - (Dminutes*60));
}
//Print values to lcd
lcd.print(Dminutes);
lcd.print(":");
if (Dseconds < 10) {
lcd.print(0);
}
lcd.print(Dseconds);
}
Any suggestions? My guess was that the XBee receiving buffer was filling up too quickly and the bytes were being dropped, but that doesn’t seem to be the case.