E-textiles & Wearables II

Assignment

• Build your own soft actuators and sensors
• Integrate them in a working project
• Document what you did
• Include all source files

How will it be evaluated

• Student has developed soft actuators and sensors
• Student demonstrated understanding of the basic principles involved

Files

All the files created for this assignment can be downloaded by clicking on the link bellow:

General Idea

The assignment for this week was to create an interactive project, so having in mind my final project, I tested some motors and the posibility to sew the circuit to the fabric instead of using a PCB.

Circuit to test

I was aware that for my final project I would propably use a servo motor for moving some flaps a and a DC motor for creating thrust for moving my project through the air. So I decided to add them to my circuit and for controlling them, I thought on an ultrasonic sensor. For controlling the DC motor I needed a motor driver, for changing the 5 volt signals to 12 volt, while for the servo I did not need any driver but a pwm signal; so for processing ad sending the signals to the motors I needed a microcontroller, in this case I chose a lilypad USB board which has a microcontroller atmega328p in it. The circuit I had In mind was the following.

The capacitors connected in parallel to the 9 V source in the circuit are for eliminating high and low frequency noise and are recomended to be used with the 4953 motor driver.

Sewing The Circuit

The first thing I did was to sew thee motor driver since it was the component that had the pads closer. At a begining I tried to soldered it directly to the conductive thread, but I realizad that it was almost impossible. So to solve this I soldered the pins to copper wire and expanded them, so that the component look like an spider, and then I fixed it to the fabric with conductive thread. Once I did this I started to sew all the components to the fabric and between them. Since the copper wire I used was very brittle, I sewed very carefully directly to the terminals of the components, that way I avoided that the fabric stretched too much so that it broke the copper wire.

At a certain point I tried to test my circuit in the PC but I realized that the LyliPad had problems so I had to cut the wires that fixed the lilypad to the fabric changed it by one that worked correctly and soldered the remaining wires to it. Then I proceed to sew and solder the rest of the components and sewed the motor to the fabric with a common thread, this last action will move the fabric when the motor stops or changes it direction of spin, similar to when a car brakes suddenly and makes the passengers move.