Introduction: Making a Web-programmable, Weight-sensitive Backpack
I've been traveling a lot with my backpack, sometimes putting too much in it, which is bad for my back. Taking a cue from this weight-sensing tote on Instructables, I decided to build one using schemer.
Schemer is a tiny programmable button that helps you easily make interactive art and craft. Instead of using wires or bluetooth, you program it by holding it in front of a computer screen. You only need your web browser. No wires, and no extra hardware or software to install.
It's an experiment and part of my Ph.D. research on ambient programming and wearable computation. Check out page 2 for a brief discussion of why I think simplifying the construction and programming of wearable electronics is an important goal.
Step 1: What This Means for the Future of Etextiles (aka What's the Point?)
These factors add up, therefore sewing with conductive thread becomes a mess really quickly. We need to rethink how electronics and fabric may better coexist, and I think simplifying and reducing the number of connections is a good way to start.
I imagine a future where if I have a wearable electronic item and I need to change its behavior, I'd want to take out my phone, poke at the screen, and send the instructions to my shirt or pendant.
Currently, the typical way would be to break out the laptop (nettop), sit down, fire up an editor or development environment, type, compile, find a USB cable, download. Hopefully you brought all that, and you've already installed all the software and drivers you need.
Step 2: Ingredients, Preparation and Layout
The other components of this projects are the force sensor itself, and the custom sensor board.
Step 3: Arrangement and Sewing Data Lines
The last picture illustrates how you just need one piece of thread to connect all components together. That's what cool about the schemer bus: simplicity.
Step 4: Minus Connections for Lightboards & Sensor
Normally, I'd start sewing the minus connections now, but to make things easier (in this case), I sew down one of the inputs to the custom sensor. Leave a long piece of thread, since you'll connect it later to the force sensor.
Next, connect all the minus holes. On schemer, when you align it with the + sign up, the bottom 2 holes are all minus. For lightboard, the minus hole is opposite the dot hole, and for sensor, it is the bottom hole when the text is right-side-up.
Step 5: Battery Power
Two reasons I'm working on the schemer system:
It hit me some time ago that the traditional ways of hooking up electronics are a big roadblock to broader acceptance of etextiles: for educators, for mass manufacturers, for DIYers, for artists, and so on.
On a circuit board, you can route all the wires carefully so they don't touch. This is easier to do on a hard, fixed, 2D circuit board where you have the luxury of routing wires under and above the circuit board.
However, in the case of sewing, the thread is stitched to both sides of fabric, making this kind of routing more difficult; it's in 3D; and the whole fabric moves; so it becomes a mess really quickly. We need to rethink how to electronics and fabric may better coexist, and I think simplifying and reducing the number of connections is a good way to start.
Programmable artifacts still require a relatively beefy computer (I'm talking about the need for hardware ports, software, keyboard, etc. and not processor specs). If I have a wearable thing and I need to change its behavior, the typical way would be to sit down, fire up an editor or development environment, type, compile, find a USB cable, download.
Wearables give us a tremendous opportunity to rethink this very premise. Why can't we program directly from our phones for instance? This would be awesome especially for quick changes. Could we download a program embedded in a painting? If I was a museum curator, could I make my visitors' light-up shirts behave differently depending on the exhibit? What would that mean? How would that be possible?
I feel that web-programmable wearable buttons are a good - though tiny - step in enabling a more pedestrian approach to etextiles.
Step 6: Testing
Step 7: Force Sensor
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