RGB With SparkCore and Curl

Controlling a common RGB-LED with a Spark core and curl.

The complete code is attached.

To light up a simple rgb-LED you need:

• 1 Spark.io Spark Core
• 1 rgb-LED
• 3 220-Ω resistors
• 1 jumper
• 1 breadboard

Please wire all parts according to the scheme.

Hook up the core and claim it.

Transfer the code via the Spark core IDE.

This is the core part of the code parsing a list of numeric arguments separated by ',' into an array of double values:

for(int i=0;i<=length;i++)// parse all parts of args between the separators {
	
	if(args.charAt(i)==separator || i == length){
	String substring = args.substring(from, i);
	int bufSize = 1+ substring.length();
	char buffer[bufSize];
	substring.toCharArray(buffer, bufSize);
	double value = atof(buffer);


	*(allValues + allValuesCount)=value;
	allValuesCount++;


	if(i < length) // next substring beyond separator
	from = i+1;
	}
}

The call on a terminal-application for a yellow LED would be:

curl https://api.spark.io/v1/devices/0123456789abcdef01234567/changeColor \ -d "access_token=1234123412341234123412341234123412341234"\ -d "args=255,255,0”

Of course, the device-ID and the access-token have to be taken from the device you are working on.