Next SimpleIDE Issue: PING and 2 Servos

NWCCTV · 2014-09-04 18:47

So I know the Servos work and I know the PING works. However, in the following code only the Servo on Pin 14 will run but not the one on Pin 15. Helppppp!!!!

/*Test Ping Distance.c
Measure and display Ping))) Ultrasonic Distance Sensor distance measurements.
http://learn.parallax.com/propeller-c-simple-devices/sense-distance-ping
*/


#include "simpletools.h" // Include simpletools header
#include "ping.h" // Include ping header
#include "servo.h"
int main() // main function
{
while(1) // Repeat indefinitely
{
int cmDist = ping_cm(13); // Get cm distance from Ping)))
print("cmDist = %d\n", cmDist); // Display distance
pause(200); // Wait 1/5 second
if(cmDist <6)
{
servo_speed(14, 100); // P18 servo full speed CCW
servo_speed(15, -100); // P19 servo full speed CW
} 
else 
servo_speed(14,0);
servo_speed(15,0);
}
}

kuroneko · 2014-09-04 18:53

It would really help you if adapted some form of indentation for your C programs. The else branch only covers pin 14, the pin 15 call is always executed (which I assume is effectively a stop).

#include "simpletools.h" // Include simpletools header
#include "ping.h" // Include ping header
#include "servo.h"
int main() // main function
{
    while(1) // Repeat indefinitely
    {
        int cmDist = ping_cm(13); // Get cm distance from Ping)))
        print("cmDist = %d\n", cmDist); // Display distance
        pause(200); // Wait 1/5 second
        if(cmDist <6)
        {
            servo_speed(14, 100); // P18 servo full speed CCW
            servo_speed(15, -100); // P19 servo full speed CW
        } 
        else 
            servo_speed(14,0);
 [COLOR="#FF0000"]       servo_speed(15,0);[/COLOR]
    }
}

NWCCTV · 2014-09-04 19:40

Servos on pin 14 and 15. The one on 14 works correctly. The one on 15 does not. When I pasted my code that is how it shows up, Why would the for pin 15 always be called and not 14 if they are identical?

kuroneko · 2014-09-04 19:47

If you want the servo_speed(?, 0) calls to be executed conditionally (i.e. in the else branch, together) then you have to group them with curly brackets. This is C, not SPIN.

if(cmDist <6)
        {
            servo_speed(14, 100); // P18 servo full speed CCW
            servo_speed(15, -100); // P19 servo full speed CW
        } 
        else 
        {
            servo_speed(14,0);
            servo_speed(15,0);
        }

Your original code is equivalent to

if(cmDist <6)
        {
            servo_speed(14, 100);  // if
            servo_speed(15, -100); // if
        } 
        else
        {
            servo_speed(14,0);     // else
        }
        servo_speed(15,0);         // always

NWCCTV · 2014-09-04 19:53

Got it. Thanks for that. I think I am confusing myself because I am going back and forth between Spin and SimpleIDE. Trying to figure out which one is going to work better and require the least amount of coding.

Next SimpleIDE Issue: PING and 2 Servos

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