This sketch shows how to remote control wearable LEDs using text messages

 Messages sent over the Twilio API can be received by a GSM Module.
 We used a generic 'SIM900' based Module, but anything that understands AT-commands over UART should work as well.

 A chain of individually adressable WS2801 LEDs is controlled by the Arduino.
 The code supports current limiting to allow safe powering over USB.

 Except for the Rainbow-Fade Effect by Stefan Hintz/TrafoPop, this code is under A Creative Commons Attribution/Share-Alike License
 http:creativecommons.org/licenses/by-sa/4.0/
 (2014) by Felix Bonowski / Made for Twilio 


How to wire things up:
 
 ----------Connection to the GSM Module:--------------------------
 Our module was a bit picky about power.
 It needs AT LEAST 5.0V, anything less and it will crash erratically...
 The Arduino 5V pin actually gives you only about 4.7V because of the voltage drop across the protection diode on the Arduino board.
 The easiest way to make things work reliably is to cut a USB cable in the middle and draw power from it directly.

 So here is how you do it...
 GSM Module Ground/'-' <----> Arduino GND/0V (both connections are needed- see below!)
 GSM Module Ground/'-' <----> Cut USB cable GND (usually black) (both connections are needed- see above!)
 GSM Module 5V/'+'     <----> Cut USB cable 5V (usually red)
 GSM Module RX         <----> Arduino TX (Pin 0 on Leonardo/Micro/ProMicro, see below for Software Serial i.e. on Nano)
 GSM Module TX         <----> Arduino RX (Pin 1 on Leonardo/Micro/ProMicro, see below for Software Serial i.e. on Nano)
 GSM Module Power-On   <----> Arduino any digital Pin (#defined by 'gsmPowerPin' below)

 ----------Connection to the LEDs:--------------------------

 Any kind of WS2801 SPI-type controlled LEDs are supported.
 They can draw a low of power, so make sure you set the current limit and/or have a good USB power supply...
 It is also a good idea to put a large electrolythic capacitor (~1000µF, >=10V) in parallel to the LED Power supply
 

 Unfortunately, there is no standard color scheme for the wires, so you will have to look at the datasheet to find out.

 LED strand GND/0V/-      <----> Arduino GND and/or cut USB cable GND (usually black)
 LED strand 5V/+          <----> Arduino 5V and/or cut USB cable 5V (usually red)
 LED strand MOSI/Data in  <----> Arduino MOSI (Pin 16 on Arduino Pro Micro, Pin 11 on Arduino Nano)
 LED strand SCLK/Clock    <----> Arduino SCLK (Pin 15 on Arduino Pro Micro, Pin 13 on Arduino Nano)

 
 Have Fun!