9th Assignment l E-Textiles and Wearables

Becky Stewart gave us a follow up on wearables and e-textiles and showed us incorporating computation into soft circuits by using micro-controlers and single-board computers.

Create an interactive object; if you are already experienced with coding, focus on fully integrating a micro-contoler into a textile circuit. If you are new to coding, choose an example and get it working using your own sensors and actuators.

I wanted to create jacket that lights up when it gets dark and cold outside. I did some research about photoresistors. It is a light-controlled variable resistor, the resistance of a photoresistor decreases with increasing incident light intensity . I did not choose this photoresistor because the installation in a jacket seemed a bit to complicated in consideration of accuracy of the sensor results and the lack of prior knowledge. Therefore, I thought about the jacket again and that a simple way to work with a sensor would be when it is directly integrated and controlled by the jacket itself. I read an article in a book about textile sensors and there they propose to use a zipper as a switch to control LEDs.

I started to gather materials I planned to use:

• Microcontroller: Lillypad (lighter and more handy than an Arduino)
• conductive material/fabric (I used it as wires because I could directly iron it on the jacket and did not have to sew it. Furthermore, I could cut my pattern of 'wires' in the Lasercutter)
• LEDs (I soldered these by my own, see following short clip)
• conductive threat (to connect single components zipper and LEDs and as substitution of wires)
• resistor with 10k Ohm (to compensate too much energy)

After preparing all my components I started to design the sketch for the conductive fabric in Rhino to cut it with the Lasercutter afterwards.

Retrospectively, this was a really time intensive work. It was important to work with the real data of the Lilypad (48mm in diameter) to have the correct measurements for your fabric. For correct meassurements and detailed parts I agree to lassercut it but if there are parts missing you can even cut it with a scissor.

I started to connect all single components, I started to sew the conductive threat on the upper third of the zipper along each teeth. I did this for both sides

(image is following). After I finished lasercutting I placed the Lilypad in a proper position on the back and ironed accordingly the conductive fabric. It was really important that non of the wires are touching to maintain a circuit which is only closed, when the zipper is pulled-up.

The next step was to connect the ironed fabric to the LEDs. I sew it on the outside of the jacket with conductive threat, on side of the LED to ground (negative) and the other side to the corresponding (positive) pin on the Lilypad. The wholes in the LEDs were really small therefore I had difficulties to find a needle for sewing. But I finally fixed each side of LEDs with 2 or 3 stiches on the jacket. In total I sewed 4 LED on my jacket.

Before I sewed the Lilypad as well with conductive threats on the place I determined beforehand I uploaded the code Blink for the LEDs on it.

I just had to adjust my pins where I connected the LEDs to.

I sewed the Lilypad and due to time issues I did not manage to integrate a battery into the jacket to make it completely wireless therefore I had to connect it with a computer due to power issues.

You can see the final jacket in the following clip