Last year there are two kind of codes to drive the servo. Most group used 1st one. Eric and I used 2nd one.
Make sure your battery is fully charged. Otherwise USB cable do not have sufficient power to run both servo.
Servo
#include “simpletools.h” // Include simple tools
#include “servo.h”
int main() // Main function
{
print(“Hello!”); // Display test message
while(1)
{
pulse_out(12, 750); //pulse out port 12
pulse_out(13, 750); //pulse out port 13
pause(20);
}
}
Ensure your servos are attached to ports 12 and 13 on the board. Make sure the connections are correct (red line = 5V, black line = ground, white = signal)
Make sure your power switch on the board is set to position 2 when you load the program.
Since most groups already centered the servo last year, this program gives the command for the servos to be stopped. but some servos will spin when you load this (they need to be calibrated).
Calibrate Servo
– While the program runs, adjust the centering screw on the side of the servo body so that the motion stops. Do this for both servos.
– After centering, try rerunning the program replacing 750 with 850 and 650 (which should produce maximum speeds in opposit directions)
Code 2
#include “simpletools.h” // Include simple tools
#include “servodiffdrive.h”
int main() // Main function
{
drive_pins(12,13); //( port, port)
drive_speeds(0,0); //(speed, speed) max 200, or -200
}
This is a shorter code to run servo, but it required to re-centering for most of servos.
QTIs:
Wire your QTI sensors so that the white line = 5v, black line is ground, and red is signal (note how this convention is different from the servos). Connect the signal line to any IO port (eg. P0).
To get the status of the QTI sensor run the following code:
#include “simpletools.h” // Include simple tools
int main() // Main function
{
int LL = 0; // left most sensor
int LC = 0; // left center sensor
int RC = 0; // right center sensor
int RR = 0; // right right sensor
while(1)
{
high(0); //output 3.3 volts to P0
high(1);
high(2);
high(3);
pause(1); //1 ms wait for sensor capacitors to charge up
LL = input(0); // this call makes the port P0 switch from output to input
LC = input(1);
RC = input(2);
RR = input(3);
LL = input(0);
LC = input(1);
RC = input(2);
RR = input(3);
pause(500); //print update rate
print (“\n”);
print (“%d”,LL); //display sensor readings
print (“%d”,LC);
print (“%d”,RC);
print (“%d”,RR);
}
}
Note for this code to work properly your QTI signal lines need to be attached to P0, P1, P2, and P3 respectively.