Hi,
I am working on a project that has an m3pi talking over Xbee, and as an intermediary step i have code that will talk back and forth with the m3pi.
I found it somewhat challenging to get messages back and forth from the m3pi because the mbed serial library doesn’t have a thing similar to serial.readString() in arduino, thus i had to write code to loop through the chars.
I figure this may be useful for anyone getting started with the m3pi and xbees.
I am going to assume a reader is familiar with how to use the m3PI, mbed, and xbees in other contexts.
I bought two xbees and the xbee explorer from sparkfun.
sparkfun.com/products/11812
sparkfun.com/products/8665 X 2
pololu.com/product/2153
I put the code below onto the mbed
the code will send out on the xbee that value “Z is %d\n”,z once every three seconds
anything you send in will be printed to the LCD screen on the m3pi.
#include "mbed.h"
#include "m3pi.h"
// works - will send messages to m3pi that are then displayed.
m3pi m3pi;
Serial mySerialDevice(p28, p27);
int n = 1; // for looping thu char array
int z = 1;
int loopCount = 1;
char messageIn[50];
char messageToSend[50];
char nxtChr;
void obtainSerialData();
void sendSerialData(char messageOut[]);
int main() {
mySerialDevice.baud(9600);
wait(1);
while (1) {
obtainSerialData();
m3pi.cls();
m3pi.locate(0,0);
m3pi.printf(messageIn);
wait(1.5);
sprintf(messageToSend,"Z is %d\n",z);
sendSerialData(messageToSend);
wait(1.5);
z++;
} // end of the while loop
} // end of the main function
void obtainSerialData()
{
n = 0;
while (mySerialDevice.readable())
{
nxtChr = mySerialDevice.getc();
messageIn[n] = nxtChr;
if (nxtChr == '\0')
{
break;
}
if (nxtChr == '\n')
{
messageIn[n] = '\0';
break;
}
n++;
}
}
void sendSerialData(char messageOut[])
{
int n=0;
while (1)
{
mySerialDevice.putc(messageOut[n]);
if (messageOut[n] == '\0')
{
break;
}
n++;
}
}
I then used the serial monitor in the arduino environment and hooked it to my com port for the xbee. when i switched on the m3pi, i saw that the serial port on my computer shows the “Z = 1” message from my m3pi. When I wrote text into my serial monitor, it came out on the m3pi.
