Page 367 - Hacking Roomba

348 Part III — More Complex Interfacing

Listing 15-3 Continued

vhi,vlo,rhi,rlo);
char cmd[5] = {137, vhi,vlo, rhi,rlo}; // DRIVE
int n = write(roomba->fd, cmd, 5);
if( n!=5 )
perror(“roomba_drive: couldn’t write to roomba”);
}
int roomba_read_sensors(Roomba* roomba)
{
char cmd[2] = {142, 0}; // SENSOR, get all sensor data
int n = write(roomba->fd, cmd, 2);
roomba_delay(COMMANDPAUSE_MILLIS);
n = read(roomba->fd, roomba->sensor_bytes, 26);
if( n!=26 ) {
if(roombadebug) fprintf(stderr,
“roomba_read_sensors: not enough read
(n=%d)\n”,n);
return -1;
}
return 0;
}

On Mac OS X and Linux desktop systems, you can compile the program by simply typing
make in the directory, and the Makefile will build it for you:
demo% wget http://roombahacking.com/software/roombacmd/roombacmd-
1.0.tar.gz
demo% tar xzf roombacmd-1.0.tar.gz
demo% cd roombacmd
demo% make
gcc -Wall -I. roombacmd.c roombalib.c -o roombacmd
You can then run it with no arguments to see how to use it, as in Listing 15-4. This com-
piled version of roombacmd isn’t usable in OpenWrt, but you can test it before making an
OpenWrt version.

Listing 15-4: roombacmd Usage

demo% ./roombacmd
Usage: roombacmd -p <serialport> [OPTIONS]
Options:
-h, -- help Print this help message
-p, -- port=serialport Serial port roomba is on