This week I chose to start a multi week project to combine the next few assignments. The problem is interfacing with my iphone while driving my scooter. This may be to answer a phone call or adjust the volume of the music. Apple makes a simple button interface with a mic that is integrated into the Apple earphones. This is tough to use while driving because it requires me to take my hands off the handlebars. It is increasingly difficult while wearing gloves and a helmet. I started by making a "power glove" with buttons embedded in the finger tips. This would allow me to click without letting go.
I started in Eagle by designing a chip small enough to fit on the back of my hand and thin enough to not impair the movement of the glove or create a bulge in the fabric. I tried to eliminate all unnecessary components. The ISP header was not soldered to the board but was connected only for programming.
I had a difficult time reading the serial data from my chip. I knew it was sending data because my FTDI cable had a LED on it. When ever I pressed the buttons on my glove the light would blink. After installing PySerial and several other serial interfaces as well as error checking my program and missing libraries I finally found that my FTDI driver was not installed. I could not run term.py because their was no USB Serial file in the /dev directory after a while I finally was able to run it at a speed of 9600.
I programmed my chip to display "volume up" when I released one button, "volume down" when I released the other and "answer phone" when I tapped them both. It's curious that when I tested the glove, the displaying characters were "n", "p" and "np" respectively. I'm not sure where these characters are coming from because they are not part of my embedded C program.