For this project, I made a textile interface that acts as a controller for Ableton Live. This project was an exploration in soft materials and rapid prototyping over the course of a weekend. You can see the full documentation of the process here.
I used the following technologies and softwares:
Arduino
Velostat pressure-sensing material
Conductive fabric
Neoprene
Laser cutter
Conductive thread
Vectorworks
MaxMSP
Ableton Live
C++
OSC/UDP network communication
For my final project, I wanted to create an interface that could be used wirelessly to control a software musical instrument. I drew a design by hand that upon reflection somewhat resembles a whale, as you can see below. I felt like some soft curves would be apropos given the soft nature of the technology we were employing.
Since I was going to be using Velostat buttons, I would be using two pieces of conductive fabric ironed on to neoprene backing layers with the Velostat in the middle. So considerations had to be made for the mirror image of each side of the buttons.
Since we had been using Vectorworks in my Digital Fabrication class, I took to Vectorworks to model the pieces which I could laser cut. I could not cut the neoprene on our laser cutters unfortunately; it is a somewhat toxic material. But I did cut a paper version which I traced on to the neoprene. Here are some photos. The neoprene is pink on the outside and black on the inside. You can see the two conductive fabric layers below in silver pattern and the black Velostat on top of one side. You can also see the blue wire wrap that I planned to use.
The conductive fabric laser cut quite well.
Here are all the pieces ready to be put together.
One challenge for me, and many textile interface designers it seems, is how to go from something soft to something hard, like metal connector or wire. I first did a test by sewing wire wrap straight on to the conductive fabric using conductive thread. I thought this worked pretty well as far as connectivity, but I didn’t think it would be sustainable as I felt the wire wrap would eventually wear out the Velostat and poke through.
I did use this first technique of sewing the wire wrap directly on to the conductive fabric for the bottom section where the + voltage would flow. I figured I could get away with this because the connection was in a place that was not where the buttons would be pressed. I also added some fabric glue which you can see and used some traditional yellow thread to keep the wire wrap in place.
I made some measurements before ironing on the conductive fabric to the inside of the top layer so that the top and bottom layers would line up. I found a purple paint pen to be more useful than a black sharpie.
After I ironed on the conductive fabric to the neoprene, I realized that I should have included tabs in my design. Luckily, I didn’t iron on the pieces too thoroughly and was able to pull up the top and sew conductive threat into the pieces. I didn’t sew through the neoprene though as I didn’t want to run into shorts when I use the interface.
From here, I didn’t want to use the conductive thread to go all the way to the Arduino, as I was envisioning a multi-pin connector on the other end. So I looped the end of some wire wrap, threaded conductive threat into the wire and then sewed the wire and conductive thread onto the neoprene. I added some fabric glue to tie it all together. I wasn’t entirely happy with this either though as I thought I could run into some issues with the bottom layer shorting with the conductive thread where the Velostat wasn’t covering.
Here’s the fabric glue that I found in our Soft Lab at ITP.
I improvised a different kind of connection, wrapping the conductive thread around the wire wrap and then looping the wire wrap around itself. I closed this with tape and then enclosed that all in shrink wrap to seal the connection. I thought this worked pretty well.
I then sewed the wire wrap down with regular yellow thread and began to sew the Velostat over the conductive fabric. I had hoped to use a sewing machine but was apprehensive since the noeprene seemed flimsy. In the future, I am definitely going to try it as the hand sewn look was not as charming as I had hoped.
Once all the Velostat was sewed on, it was time to put the bottom and top neoprene pieces together. Here you can see the finished product. I stopped sewing the layers together once I got a decent fit as I am leaving this as a working prototype. I would like to try again but using the sewing machine next time.
Here is a shot of the interface connecting to Arduino. This is a MKR 1010 board which is nice because I can use an OSC bundle to send the full range of data from each of the Velostat buttons to many different programs. You can check out the code on my Github page here to see this implemented.
You can see the multi-pin connector in this photo below. This is useful as I can reuse it each time to patch in to the Arduino instead of having a lot of loose wires. This is a design feature I was pretty proud of. You can see where I made loops to connect it to the top of the whale :)
Here is a video of the piece working! I was sending the button values via OSC to MaxMSP and from there sending MIDI notes to Ableton Live. Enjoy! :)
For this lab, we were to create one Velostat sensor and run it on our Arduino. Here you can see that the button is turning on an LED. Since this sensor is read by the analog pins on the Arduino, you get a value from 0 to 1024. In order to light the LED, you simply choose a threshold level between 0 and 1024, depending on the readings you get in the Serial Monitor.
Here is the Velostat button above before being glued together. The two conductive pieces of silver fabric are separated by the black Velostat piece. The Velostat will change resistance as pressure is applied to it, passing more or less current.
Here is a similar analog sensor setup as the Velostat but with a stretch fabric sensor.
For this lab, we simply created a number of simple circuits using conductive fabric and conductive to switch on an LED.
Here is an example of a bridge switch using flannel and iron-on conductive fabric to “bridge” the gap in the circuit.
Here, I made a switch using my belt buckle and conductive thread. When the belt is buckled, conductive thread in the eyelet makes contact with the metal buckle, which has conducive thread wrapped attached at the other end. The circuit is then closed, giving power to the green LED below the video text.
