Arduino Mega Serials Not Reading In

Projects Networking, Protocols, and Devices
1

I'm having difficulty getting the multiple serial ports on my Arduino Mega to read in properly. I have the current setup:

RX0/TX0 - HC-05 (slave mode, sending the data from the other serial ports to my computer to be displayed in the serial port)
RX1/TX1 - HC-05 (master mode, receiving data from a separate MC to be eventually pushed to my computer)
RX2/TX2 - JY901 Gyroscope (gathering the angle of pitch to determine the angle my eventual device is being held at)

Not connected yet
RX3/TX3 - RS400 (Rangefinder to determine the distance from my device to point "B") - I have not connected this in yet as I want to integrate one element at a time.
~~ ~~

I am able to get both HC-05's to read in, however I'm not having success with reading in my angle from the JY901. When I connect the JY901 directly to RX0/TX0 with no other elements and run the basic code, it reads in fine. However, I'm making some error in the implementation phase and I'm not sure where it is.

Here is the code I'm currently using to read two serial devices and sending one serial device to my computer:

#include <JY901.h>
#include <Wire.h>
#include <EasyTransfer.h>

//#include <avr/power.h>
//#include <RFM12B_arssi.h>
//#include <SPI.h>
//#include <SPIFlash.h>

#define range   1

char temperatureChar[10];
char humidityChar [10];
char windChar [10];




struct Weather_Data_Structure
{
  float temperature;
  float humidity;
  float wind;
};

struct Acknowledge
{
  boolean received = false;
};


Weather_Data_Structure data;
Acknowledge acknowledge;

EasyTransfer ETin, ETout;

void setup() {
  Serial.begin(9600);
  Serial1.begin(9600);
  Serial2.begin(9600);
  ETin.begin(details(data), &Serial1);
  ETout.begin(details(acknowledge), &Serial1);
  
}

void loop() {
  
 
    Serial.print("Angle: ");      
    Serial.println((float)JY901.stcAngle.Angle[1]/32768*180);  //Call the value stored in this function and print it out Serial

  if(ETin.receiveData()){
      
    //Serial.print ("data received");
    String temperatureString = String(data.temperature,1);
    temperatureString.toCharArray(temperatureChar,10);
    Serial.print(temperatureChar); Serial.println(" C Degrees");
     
    String humidString = String(data.humidity,1);
    humidString.toCharArray(humidityChar,10);
    Serial.print(humidityChar); Serial.println("% Humidity");
    
    String windString = String(data.wind,1);
    windString.toCharArray(windChar,10);
    Serial.print(windChar); Serial.println(" m/s");
    
    Serial.println(" ");

    //ETout.sendData();
  } 
 
  delay(10000);
  acknowledge.received = 0;
  }
  

void serialEvent() 
{
  while (Serial2.available()) 
  {
    JY901.CopeSerialData(Serial2.read()); //Call JY901 data cope function
  } 
}

Here's the code I use when only running the JY901 while collecting all the data it collects:

#include <Wire.h>
#include <JY901.h>
/*
Test on Uno R3.
JY901   UnoR3
TX <---> 0(Rx)
*/
void setup() 
{
  Serial.begin(9600);
  Serial1.begin(9600);
}

void loop() 
{
  //print received data. Data was received in serialEvent;
  Serial.print("Time:20");Serial.print(JY901.stcTime.ucYear);Serial.print("-");Serial.print(JY901.stcTime.ucMonth);Serial.print("-");Serial.print(JY901.stcTime.ucDay);
  Serial.print(" ");Serial.print(JY901.stcTime.ucHour);Serial.print(":");Serial.print(JY901.stcTime.ucMinute);Serial.print(":");Serial.println((float)JY901.stcTime.ucSecond+(float)JY901.stcTime.usMiliSecond/1000);
               
  Serial.print("Acc:");Serial.print((float)JY901.stcAcc.a[0]/32768*16);Serial.print(" ");Serial.print((float)JY901.stcAcc.a[1]/32768*16);Serial.print(" ");Serial.println((float)JY901.stcAcc.a[2]/32768*16);
  
  Serial.print("Gyro:");Serial.print((float)JY901.stcGyro.w[0]/32768*2000);Serial.print(" ");Serial.print((float)JY901.stcGyro.w[1]/32768*2000);Serial.print(" ");Serial.println((float)JY901.stcGyro.w[2]/32768*2000);
  
  Serial.print("Angle:");Serial.print((float)JY901.stcAngle.Angle[0]/32768*180);Serial.print(" ");Serial.print((float)JY901.stcAngle.Angle[1]/32768*180);Serial.print(" ");Serial.println((float)JY901.stcAngle.Angle[2]/32768*180);
  
  Serial.print("Mag:");Serial.print(JY901.stcMag.h[0]);Serial.print(" ");Serial.print(JY901.stcMag.h[1]);Serial.print(" ");Serial.println(JY901.stcMag.h[2]);
  
  Serial.print("Pressure:");Serial.print(JY901.stcPress.lPressure);Serial.print(" ");Serial.println((float)JY901.stcPress.lAltitude/100);
  
  Serial.print("DStatus:");Serial.print(JY901.stcDStatus.sDStatus[0]);Serial.print(" ");Serial.print(JY901.stcDStatus.sDStatus[1]);Serial.print(" ");Serial.print(JY901.stcDStatus.sDStatus[2]);Serial.print(" ");Serial.println(JY901.stcDStatus.sDStatus[3]);
  
  Serial.print("Longitude:");Serial.print(JY901.stcLonLat.lLon/10000000);Serial.print("Deg");Serial.print((double)(JY901.stcLonLat.lLon % 10000000)/1e5);Serial.print("m Lattitude:");
  Serial.print(JY901.stcLonLat.lLat/10000000);Serial.print("Deg");Serial.print((double)(JY901.stcLonLat.lLat % 10000000)/1e5);Serial.println("m");
  
  Serial.print("GPSHeight:");Serial.print((float)JY901.stcGPSV.sGPSHeight/10);Serial.print("m GPSYaw:");Serial.print((float)JY901.stcGPSV.sGPSYaw/10);Serial.print("Deg GPSV:");Serial.print((float)JY901.stcGPSV.lGPSVelocity/1000);Serial.println("km/h");
  
  Serial.println("");
  delay(500);
}

/*
  SerialEvent occurs whenever a new data comes in the
 hardware serial RX.  This routine is run between each
 time loop() runs, so using delay inside loop can delay
 response.  Multiple bytes of data may be available.
 */
void serialEvent() 
{
  while (Serial1.available()) 
  {
    JY901.CopeSerialData(Serial1.read()); //Call JY901 data cope function
  }
}

I only need to access the second value stored for the Angle in the above code, so I created this reduced sketch and it runs and outputs the needed value perfectly fine when it is the only device connected (i.e. RX0/TX0 and the Mega is connected via USB to my computer):

#include <Wire.h>
#include <JY901.h>
/*
Test on Uno R3.
JY901   UnoR3
TX <---> 0(Rx)
*/
void setup() 
{
  Serial.begin(9600);
}

void loop() 
{
  //print received data. Data was received in serialEvent;
  Serial.print("Angle:");
  //Serial.print((float)JY901.stcAngle.Angle[0]/32768*180);
  //Serial.print(" ");
  Serial.print((float)JY901.stcAngle.Angle[1]/32768*180);
  //Serial.print(" ");
  //Serial.println((float)JY901.stcAngle.Angle[2]/32768*180);
  
  Serial.println("");
  delay(2000);
}
/*
  SerialEvent occurs whenever a new data comes in the
 hardware serial RX.  This routine is run between each
 time loop() runs, so using delay inside loop can delay
 response.  Multiple bytes of data may be available.
 */
void serialEvent() 
{
while (Serial.available()) 
  {
    JY901.CopeSerialData(Serial.read()); //Call JY901 data cope function
  }
}

I know my mistake is happening in the implementation of the JY901 as I'm able to get my serial monitor to print:

Angle 0.00
22.4 C Degrees
46.7% Humidity
0.0 m/s

I'm just not understanding why the value stored for the angle is not being properly called from the respective serial bus as defined in the void function "serialEvent" in the first code posted above.

Thanks for any and all help.

2

Your description is rather confusing. It is not a good idea to connect your HC05 to Rx0 and Tx0 because those pins are used by Serial for communicating with the Arduino Serial Monitor.

Don't use serialEvent(). It is only triggered by data in the Serial input buffer - not by Serial1, Serial2 or Serial3. It does not do anything useful for Serial either.

Have a look at the examples in Serial Input Basics - simple reliable ways to receive data. You can create a separate function and associated variables for each Serial port.

...R

3

Is it still an issue to connect the HC05 to Rx0 and Tx0 when I've got the Mega not connected to the computer? When I run my final code I have it powered off of a battery and figured the Rx0/Tx0 would be fine to use since the USB isn't being powered.

That's a really good point about serialEvent as when I have it connected to any input except Rx0/Tx0 is doesn't read a value in, because it isn't being directed to do that. Thank you.

I've read that page up and down but I'll give it another go. Is it as simple as and if statement about Serial1 or Serial2 and then reading in that data?

Ultimately my goal is to have Serial1,2,3 read in data then push it out Serial through my HC05 to a computer. The whole system will be powered by battery and will have no hard connection to the computer except through the HC05 connected to Rx0/Tx0.

Thank you for your speedy response and help Robin2.

4

arduino_student_17:
Is it still an issue to connect the HC05 to Rx0 and Tx0 when I've got the Mega not connected to the computer?

That will work fine. But during program development it may be better to keep Rx0 and Tx0 free.

Is it as simple as and if statement about Serial1 or Serial2 and then reading in that data?

I don't understand what you are asking.

The way I would do it is have a function (copied from my tutorial) called (say) recvSerial1WithEndMarker() for the Serial1 input and another called recvSerial2WithEndMarker() for the Serial2 input etc

...R