BBB code/old/ActuatorHandler_real.c

   1 #include "pwm.h"
   2
   3 char pin_dir = "/sys/class/gpio/gpio";
   4 int pwm_active = 0;
   5
   6 /** Sets a GPIO pin to the desired value
   7 *       @param value - the value (1 or 0) to write to the pin
   8 *       @param pin_num - the number of the pin (refer to electronics team)
   9 */
  10
  11 void SetPin(int value, int pin_num) {
  12         int pin;
  13         char buffer[10];
  14         char pin_path[40];
  15         snprintf(pin_path, sizeof(pin_path), "%s%d%s", pin_dir, pin_num, "/value");     //create pin path
  16         pin = open(pin_path, O_WRONLY);
  17         if (pin < 0) perror("Failed to open pin");
  18         if (value) {
  19                 strncpy(buffer, "1", ARRAY_SIZE(buffer) - 1);
  20         }
  21         else {
  22                 strncpy(buffer, "0", ARRAY_SIZE(buffer) - 1);
  23         }
  24         int write = write(pin, buffer, strlen(buffer));
  25         if (write < 0) perror ("Failed to write to pin");
  26         close(pin);
  27 }
  28
  29 //TODO: Be able to write to multiple PWM modules - easy to change
  30 //              but current unsure about how many PWM signals we need
  31
  32 void ActuatorHandler(FCGIContext *context, ActuatorId id, const char *set_value) {
  33         char *ptr;
  34
  35         switch(id) {                                    //Add new actuators here
  36                 case ACT_PRESSURE:                      //Suppose is pressure regulator. 0-700 input (kPa)
  37                 {
  38                         if (pwm_active == 0) {  //if inactive, start the pwm module
  39                                 pwm_init();
  40                                 pwm_start();
  41                                 pwm_set_period(FREQ);                           //50Hz defined in pwm header file
  42                         }
  43                         int value = strtol(set_value, &ptr, 10);
  44                         //Beaglebone code
  45                         if(value >= 0 && value <= 700) {
  46                                 double duty = value/700 * 100;          //convert pressure to duty percentage
  47                                 pwm_set_duty((int)duty);                        //set duty percentage for actuator
  48                         }
  49                         //server code
  50                         if (*ptr == '\0' && value >= 0 && value <= 700) {
  51                                 FCGI_BeginJSON(context, STATUS_OK);
  52                                 FCGI_JSONKey("description");
  53                                 FCGI_JSONValue("\"Set pressure to %d kPa!\"", value);
  54                                 FCGI_EndJSON();
  55                         } else {
  56                                 FCGI_RejectJSONEx(context,
  57                                         STATUS_ERROR, "Invalid pressure specified.");
  58                         }
  59                 } break;
  60                 case ACT_SOLENOID1:
  61                 {
  62                         int value = strtol(set_value, &ptr, 10);
  63                         if (*ptr == '\0') {
  64                                                                                 //code to set pin to value
  65                                 SetPin(value, 1);               //"1" will need to be changed to pin numbers decided by electronics team
  66                                                                                 //code for server
  67                                 const char *state = "off";
  68                                 if (value)
  69                                         state = "on";
  70                                 FCGI_BeginJSON(context, STATUS_OK);
  71                                 FCGI_JSONKey("description");
  72                                 FCGI_JSONValue("\"Solenoid 1 turned %s!\"", state);
  73                                 FCGI_EndJSON();
  74                         } else {
  75                                 FCGI_RejectJSON(context, "Invalid actuator value specified");
  76                         }
  77                 } break;
  78                 default:
  79                         FCGI_RejectJSONEx(context,
  80                                 STATUS_ERROR, "Invalid actuator id specified.");
  81         }
  82 }