After freezing my ass off at Burning Man last year, and after discovering EL wire at Burning Man, I decided I wanted to make myself some kind of incredibly warm, pimped out coat which glowed. But rather than siimply glow, I wanted it to change colors in some dynamic way. I settled on the idea of having it change colors based on which direction I was facing.

This early version used this EL Sequencer from Sparkfun to turn on different strands of EL wire based on the heading returned by a HMC6352 Compass Module. 

I ended up abandoning this approach and instead using an LED strip which could blend seamlessly from one color to another. 

I’m posting this mainly so I can link to this tutorial on using the Sparkfun EL Sequencer. It’s probably the worst documented thing I’ve ever bought, and without the tutorial, I never would have gotten it working. That said, the sequencer works well once you decipher it via that tutorial. 

Also for reference- I learned how to hook up the HMC6352 Compass Module by following this useful post.

In the video above, the EL Sequencer was programmed with the following sketch:

 

//All this does is read the heading from HMC6352 and spit it out via serial

#include <Wire.h>
int HMC6352SlaveAddress = 0x42;
int HMC6352ReadAddress = 0x41; //"A" in hex, A command is: 
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
// turn a given EL wire segment on or off. 'num' is between 0 and 7, corresponding
// to EL segments 'A' through 'H'.  if 'value' is true, the segment will be lit.
// if value is false, the segment will be dark.
void elSegment(byte num, boolean value) {
  digitalWrite(num + 2, value ? HIGH : LOW);
}

int headingValue;

void setup(){
    // set up the EL wire segment pins
  byte i;
  for (i = 2; i < 10; i++) {
    pinMode(i, OUTPUT);
    digitalWrite(i, LOW);
  }
  // "The Wire library uses 7 bit addresses throughout. 
  //If you have a datasheet or sample code that uses 8 bit address, 
  //you'll want to drop the low bit (i.e. shift the value one bit to the right), 
  //yielding an address between 0 and 127."
  HMC6352SlaveAddress = HMC6352SlaveAddress >> 1; // I know 0x42 is less than 127, but this is still required

  Serial.begin(9600);
  Wire.begin();
}

void loop(){
  //"Get Data. Compensate and Calculate New Heading"
  Wire.beginTransmission(HMC6352SlaveAddress);
  Wire.send(HMC6352ReadAddress);              // The "Get Data" command
  Wire.endTransmission();

  //time delays required by HMC6352 upon receipt of the command
  //Get Data. Compensate and Calculate New Heading : 6ms
  delay(6);

  Wire.requestFrom(HMC6352SlaveAddress, 2); //get the two data bytes, MSB and LSB

  //"The heading output data will be the value in tenths of degrees
  //from zero to 3599 and provided in binary format over the two bytes."
  byte MSB = Wire.receive();
  byte LSB = Wire.receive();

  float headingSum = (MSB << 8) + LSB; //(MSB / LSB sum)
  float headingInt = headingSum / 10; 
  
  if (headingInt>337 && headingInt<361) { 
    Serial.println(" North");
    elSegment(0,true);
    elSegment(1,false);
    elSegment(2,false);
    elSegment(3,false);
  }
  else if (headingInt>0 && headingInt<23) {
    Serial.println("North");
    elSegment(0,true);
    elSegment(1,false);
    elSegment(2,false);
    elSegment(3,false);
  }
    else if (headingInt>24 && headingInt<67) {
    Serial.println("North East");
    elSegment(0,true);
    elSegment(1,true);
    elSegment(2,false);
    elSegment(3,false);
  }
    else if (headingInt>68 && headingInt<112) {
    Serial.println("East");
    elSegment(0,false);
    elSegment(1,true);
    elSegment(2,false);
    elSegment(3,false);
  }
    else if (headingInt>113 && headingInt<157) {
    Serial.println("South East");
    elSegment(0,false);
    elSegment(1,true);
    elSegment(2,true);
    elSegment(3,false);
  }
    else if (headingInt>158 && headingInt<202) {
    Serial.println("South");
    elSegment(0,false);
    elSegment(1,false);
    elSegment(2,true);
    elSegment(3,false);
  }
    else if (headingInt>203 && headingInt<247) {
    Serial.println("South West");
    elSegment(0,false);
    elSegment(1,false);
    elSegment(2,true);
    elSegment(3,true);
  }
    else if (headingInt>248 && headingInt<292) {
    Serial.println("West");
    elSegment(0,false);
    elSegment(1,false);
    elSegment(2,false);
    elSegment(3,true);
  }
     else if (headingInt>293 && headingInt<336) {
    Serial.println("North West");
    elSegment(0,true);
    elSegment(1,false);
    elSegment(2,false);
    elSegment(3,true);
  }

  delay(100);
}