I wanted to make a wearable digital compass, that would point to a destination you give it, instead of pointing North. Here is the process I went through, the successes and the failures.

The Parts

I ordered my parts from sparkfun. I got an ATtiny85 which I could program with the Arduino Uno, a compass module, and ripped some lights out of a children’s shoe (actually Bona did this part for her own project and donated the extra pink ones to me!). Eventually I thought this wearable would use bluetooth to communicate with a cellphone to get current GPS location and destination location, but I left this part out for this iteration. The locations will be hardcoded for now.

Testing the Compass Module

The module was actually fairly easy to setup. It has a breakout board and code posted on sparkfun. I used a variant of the code posted on bildr.org to get a simple circuit to point north. Here I’m using 4 lights instead of 8 like I did in the midterm.

Video: to be posted soon

Then I wrote a script so that it would take two points, where you are and where you want to go, (each with a latitude and longitude) and your heading from the compass, and point in the direction of your destination.

Programming the ATtiny85

I was pretty excited about this part. The ATtiny85 is pretty tiny so it seems it would be great for wearables. However, I soon realized that that the tiny was too tiny for my project, because I needed at least 6 pins (4 lights and 2 for the compass) and it only had 5. Plus some of the functions used by the compass module are not supported by the ATtiny. Doh!

But before I realized all this, I followed the tutorial at High-Low Tech and got my ATtiny to make a blinking light! Pretty cool huh?

Video: https://vimeo.com/55919894

The Wearable’s Shape Part 1: Clip-On Compass

At one point, I considered using a hard shelled bracelet, like a bangle, so that it could accomodate all the hardware. But that style was not at all in my vision, plus I would never wear a bangle, it’s just not me. My compass was more for someone who was on a hike, a bike ride, or an urban wandering walk. I wanted it to be a bit sporty, a bit rugged.

I designed a clip-on compass made of fabric, that you could clip to your bag or clothes.

To make it compact, I thought I stack everything on top of each other…

But as soon as I started sewing it, it became clear why that was a bad idea.

It was getting messy. I wouldn’t be able to control the thread from crossing and short-circuiting.

The Wearable’s Shape Part 2: Wristband

So I went back to my original idea of a wristband. I could spread out the hardware a bit more, than trying to stack them. I found this awesome armband at the Army/Navy story on 8th street between 5th and 6th avenue. It’s for service men and women to put their watch. It’s a little hard to see in the photo but it has velcro straps that go around your wrist, two smaller velcro straps inside to hold the watch face, and a velcro flap that folds over the face of the watch to protect it. This was much closer to the aesthetic I was originally thinking.

So I started to sew the compass in…

Unfortunately, this is as far as I got, because I can’t get a reading on the compass. I’m still debugging, but I’m guessing there are threads touching somewhere. I also need to solder, so that could be the issue too. But when it’s done, there will be lights on the top here:

Even if I got the sewn compass working, it’s not perfect. the lilypad is too wide for the wristband, but it would suffice for a prototype among prototypes.

I really want to continue this project and having it working. There are many more lessons to learn in this, including improving my sewing skills.

Lessons Learned the Hard Way

  1. The less hardware, the better! More hardware, makes it not so soft
  2. Stacking hardware to save space is a bad idea, especially if you don’t really know what you’re doing.
  3. Make sure your microcontroller has all the pins you need and supports your functions.
  4. You can try to plan out things in three dimensions forever. Just start making it so you can see where you fail and start remaking it sooner.
  5. Sewing a circuit is hard and time consuming, but will be easier with practice.
  6. The form is as important as the function, and deserves equal amount of time, planning, effort, stress, etc.