RFID and Servo Help Needed

NWCCTV

I am using the below code to turn a servo when a card ID matches and to stop when it does not. It is a While loop but only works the first time. When the correct card is scanned the Servo will turn, but I have tried pretty much every command in the header file and none of them will let the loop continue after the first time it starts and then stops.

/*
  RFID Read.c
  
  Reads and displays RFID tag numbers.
  
  Connect: Vcc to 5V, /ENABLE to P2, SOUT to (R = 2.2 k) to P1, GND to GND
  
  http://www.parallax.com/product/28140
*/

#include "simpletools.h"                      // Include simpletools
#include "rfidser.h"                          // Include rfidser
#include "servo.h"                            // Include servo header


int rfidEn = 2;                               // Reader /ENABLE pin to P2
int rfidSout = 1;                             // Reader SOUT pin to P1

rfidser *rfid;                                // Set up device ID

int main()                                    // Main function
{
  rfid = rfid_open(rfidSout, rfidEn);         // Open reader, start reading

  while(1)                                    // Main loop
  {
    char *str = rfid_get(rfid, 1000);         // Wait up to 1 s for card
    print("id = %s.\n", str);                 // Print ID.

   
   if(!strcmp(str, "05000038D4"))            //Check for Card match
  
    servo_speed (9,200);                     // If card matches, start servo on pin 9   

    else servo_stop();                       // If no match, do nothing 

}}

xanadu

Are you running SimpleIDE? It should throw some errors because you're missing two closing brackets.

} }

http://learn.parallax.com/propeller-c-functions

NWCCTV

Yes, The closing brackets are there. Just missed them in the Copy/Paste.

xanadu

Make sense. Did you get it working?

Usually when something doesn't work I put a bunch of debug lines to see where it is held up or looping. Then adjust the code before the debug code that isn't executed.

Andy Lindsay (Parallax)

I'd recommend using servo_disable (temporarily disable one servo) instead of servo_stop (stops the cog controlling all servos). Another thing you could do is pick one position for no card, and a different position for card detected.

For more info, click SimpleIDE's Help -> Simple Library Reference -> servo.h.

Andy

NWCCTV

Thanks Andy, I will give that a try when I get back to this project again.

NWCCTV

I tried that and I get a "undefined reference to servo_disable" error.

NWCCTV

I updated my SimpleIDE to the latest version and now I get the following error when trying to run the code from Post #1. And yes, I started with a new project.Error: RFID Read.c:35:5: error: too few arguments to function 'servo_disable'

NWCCTV

Any ideas why servo_disable does not work?

twm47099

NWCCTV wrote: »

Any ideas why servo_disable does not work?

Did you use the servo pin number as the argument to the servo_disable function? It is needed according to the documentation.

I'm not sure what will happen if the incorrect tag is read on the first try. If the servo hasn't been used, can it be disabled?

Have you just tried using servo_speed(9, 0) when incorrect?

Tom