Introduction: RGB With SparkCore and Curl

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

The complete code is attached.

Step 1: Parts and Wiring

To light up a simple rgb-LED you need:

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

Please wire all parts according to the scheme.

Step 2: Code

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; } }

Step 3: Command

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

curl \ -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.