Editing Compass Vibro Anklet Directions (section)

==Part One: Assemble Controller on Breadboard==

The controller has five parts: the Arduino, the shift register, the compass chip, the battery, and the pager motor connector.  The pager motor connector connects to the shift register.  Everything else connects to the Arduino.

Here’s a really fake diagram of that:

          
    compass chip
          |
       Arduino   ---   Shift Register ---  pager motor connector
          |
      battery

To assemble the controller on the breadboard:

1. Connect the battery to the Arduino.  The wires from the battery go into the power and ground for the Arduino.  If the battery includes a connect, you may just want to get a matching connector for the other side and attach that to the Arduino.  Alternately, if you’re feeling ambitious you could add a power switch here.

2. Connect the compass chip to the Arduino.  You’ll connect three data pins, plus power and ground, to the Arduino.  One pin is input/output: bridge together the “in” pin and the “out” pin from the compass and connect them to the same pin on the Arduino.  The other two are the clock pin and the enable pin.  These all connect to the Arduino’s output pins.  Note which pins you use, since you’ll need to update the code with that information.

3. Connect the shift register to the Arduino.  You’ll connect five data pins, plus power and ground.  One of the data pins on the shift register is the enable pin.  This pin must connect to a pin on the Arduino which is capable of PWM.  (PWM lets a digital signal simulate analog, and the enable pin needs analog input if you want to be able to vary the speed of the motors.)

4. Connect the shift register to the header socket.  Solder ribbon wire to the shift register’s output and give it a few inches of wire.  On the other side of the ribbon wire, solder a 9-pin header socket.

5. Install the Arduino IDE on your computer.  You can get the IDE here: http://www.arduino.cc/en/Main/Software

6. Connect your computer to the Arduino with a data cable (it is recommended to unplug the battery when you do so).  Make sure you’ve got a data connection.  Try running Hello World or a similar program to make sure you’ve got everything working.

7. Download the code into the Arduino.  It's on the wiki on the [[Compass Vibro Anklet Code]] page.  You will probably need to modify the Arduino code based on what you connected on the Arduino: if you connect anything differently, change the Arduino code so that it connects to the right place.  This shouldn’t be a very difficult change in the code: just change the constants to reflect where you attached each wire.

8. For testing purposes, you may want to connect the shift register to LEDs and try moving around with the breadboard.  Each LED in turn should light up as you turn around.    Note that the light will go off if you hold it in one place for a while.  This is intentional: when the motors are vibrating against your ankle, they can get very annoying and itchy if they run all the time!

When you’re done with this, you’ll have a breadboard that includes all the logic to make the device work.  You’ll have a powered digital compass.  Most likely, you’ll want to test the compass with LEDs instead of motors at this point because they’re easier.

This is a working sensor!  Now you need a display and an armature.