Revised Relay Shield Code

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1

My version allows you to control all 4 relays in one request using the following parameters -

params=R1,HIGH,R2,LOW

This can be abbreviated to -

params=R1,1,R2,0

or even -

params=1,1,2,0

int RELAY1 = D0;
int RELAY2 = D1;
int RELAY3 = D2;
int RELAY4 = D3;

void setup()
{
   //Initilize the relay control pins as output
   pinMode(RELAY1, OUTPUT);
   pinMode(RELAY2, OUTPUT);
   pinMode(RELAY3, OUTPUT);
   pinMode(RELAY4, OUTPUT);
   // Initialize all relays to an OFF state
   digitalWrite(RELAY1, LOW);
   digitalWrite(RELAY2, LOW);
   digitalWrite(RELAY3, LOW);
   digitalWrite(RELAY4, LOW);

   //register the Spark function
   Spark.function("relay", relayControl);
}

void loop()
{
   // This loops for ever
}

int tokenise(char * command, char * tokens[], int max_tokens) {
int n = 0;    
char * p = command;
    while (n<max_tokens) {
        tokens[n]=p;
        while (*p != '\0' && *p != ',') { p++; };
        if (*p == '\0') return(n+1);
        *p++ = '\0';
        n++;
    }
    return(n);
}

// command format r1,HIGH
int relayControl(String command)
{
char char_command[64];
char * tokens[20];
int token_count;
int relayNumber;
int relayState;
int n = 0;

  command.toCharArray(char_command, 64);
  token_count = tokenise(char_command, tokens, 20);
  if (token_count >=20 || token_count == 0) return(-1);
  
  while (n<token_count) {
    if (tokens[n][0] == 'R' || tokens[n][0] == 'r') relayNumber = tokens[n][1] - '0';
    else relayNumber = tokens[n][0] - '0';
    n++;
    
    relayState=-1;
    if (strncmp(tokens[n],"HIGH", 4) == 0 || strncmp(tokens[n], "1", 1) ==0 ) relayState = 1;
    else if (strncmp(tokens[n],"LOW",3) == 0 || strncmp(tokens[n], "0", 1) ==0 ) relayState = 0;
    
    n++;
    
    // do a sanity check
    if (relayNumber < 1 || relayNumber > 4 || relayState==-1) continue;

    digitalWrite(relayNumber-1, relayState);

    
  }
  
  return 1;
}
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2

@defsdoor, cool! Thanks for posting this! I’d recommend tagging it in the “Project Share” category so everyone else can take a look :smiley: