seeed_relay_test.c

/* A version of https://github.com/johnwargo/Seeed-Studio-Relay-Board/blob/master/seeed_relay_test.py in C for use with https://www.seeedstudio.com/Raspberry-Pi-Relay-Board-v1.0-p-2409.html */

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <wiringPiI2C.h>

int deviceRegMode1 = 0x06;
int deviceRegData = 0xff;

int relay (int deviceAddress, int relayNumber, int relayState) {
   int fd, relayResult;

   fd = wiringPiI2CSetup(deviceAddress);

   if(relayNumber == 1 && relayState == 1) {
       deviceRegData &= ~(0x1 << 0);
   }

   if(relayNumber == 1 && relayState == 0) {
       deviceRegData |= (0x1 << 0);
   }

   if(relayNumber == 2 && relayState == 1) {
       deviceRegData &= ~(0x1 << 1);
   }

   if(relayNumber == 2 && relayState == 0) {
       deviceRegData |= (0x1 << 1);
   }

   if(relayNumber == 3 && relayState == 1) {
       deviceRegData &= ~(0x1 << 2);
   }

   if(relayNumber == 3 && relayState == 0) {
       deviceRegData |= (0x1 << 2);
   }

   if(relayNumber == 4 && relayState == 1) {
       deviceRegData &= ~(0x1 << 3);
   }

   if(relayNumber == 4 && relayState == 0) {
       deviceRegData |= (0x1 << 3);
   }

   // All on
   if(relayNumber == 5 && relayState == 5) {
       deviceRegData &= ~(0xf << 0);
   }

   // All off
   if(relayNumber == 0 && relayState == 0) {
       deviceRegData |= (0xf << 0);
   }

   relayResult = wiringPiI2CWriteReg16(fd, deviceRegMode1, deviceRegData);

   return relayResult;
} 


int main(int argc, const char * argv[]) {
    int result;
    char rCommand[20];
   
    while(1) {
        printf("%s", "Input: ");
        fgets(rCommand,20,stdin);

        if (strcmp(rCommand, "1on\n") == 0) {
           result = relay(0x20, 1, 1);
        }
        
        if (strcmp(rCommand, "1off\n") == 0) {
           result = relay(0x20, 1, 0);
        }

        if (strcmp(rCommand, "2on\n") == 0) {
           result = relay(0x20, 2, 1);
        }
        
        if (strcmp(rCommand, "2off\n") == 0) {
           result = relay(0x20, 2, 0);
        }

        if (strcmp(rCommand, "3on\n") == 0) {
           result = relay(0x20, 3, 1);
        }
        
        if (strcmp(rCommand, "3off\n") == 0) {
           result = relay(0x20, 3, 0);
        }

        if (strcmp(rCommand, "4on\n") == 0) {
           result = relay(0x20, 4, 1);
        }
        
        if (strcmp(rCommand, "4off\n") == 0) {
           result = relay(0x20, 4, 0);
        }

        if (strcmp(rCommand, "allon\n") == 0) {
           result = relay(0x20, 5, 5);
        }
        
        if (strcmp(rCommand, "alloff\n") == 0) {
           result = relay(0x20, 0, 0);
        }

        if(result == -1) {
           printf("%s\n", "Nothing written"); 
        }
    }
}