Leah Buechley in corperation with SparkFun released the first version of the LilyPad. It seems to be a great work and I can’t wait till I get one.
View the LilyPad guide for more examples.
We will order it for EduWear, but unfortunatly it is already sold out.
So we will stick to the shield for the Arduino Mini that I verified, until there are new LilyPads availible. That is the Layout in Eagle and here is a pic of the layout.
Sewing on to a PCB is one of the ways to connect textiles to electronic as we know from xslab, Leah Buechley or the Bling Cricket. To do it with Arduino I made this shield for the mini:
On the frontside you have the controller and a power source
the actual board layout sits on the backside. I connected the reset to 5V to prevent random resets.
Once I tested it I will blog the eagle files.
Although we agreed on working on a textile pcb, we tried ease the connection between a “regular” pcb and textile materials (e.g. conductive yarns). One solution is to sew directly to the pcb (as you can do it on the very nice Bling Cricket)but it has to be done neatly what is quite hard for a lot of children (and adults 
). At our meeting in Sweden we could work together on different solutions.
The Textilhögskolan has a lot of very advanced machines but for today we sticked with snap-button and button tools.
What came out is a pcb that has snap buttons pressed on.
Most schools do not have the tools required to work with the electronic/textile combination. Therefore we packed a teacher’s kit in addition to the kit for children.
As you can see, we have a multimeter, special scissors that work with the conductive yarn, clips, cable, a battery and connector, the board, examples (i.e. prepared gloves that can act as sensors), a textile bus (to demonstrate basic principles of electronics), software, sensors/actuators, fabric, a manual and yarn.
There are still parts we are not sure about: do we need a lab power supply, a soldering iron and a breadboard?
The basic kit for beginners to learn about circuits has a databus with gaps and is connected to a power source. As the circuit is not closed the actuator patch (here an LED) won’t work.
Now the learners can close the gap and make the led light up by using various textile techniques (in the example sewing and glueing).
Or by adding switches to the circuit.
The circuit then can be attached to a piece of cloth or bag or anything else.
The more advanced learners will program a microcontroller that is connected to the bus in order to use more advanced sensor e.g. the stretch sensor.
The learner can either attach the sensor and actuators directly to the patch or put them somewhere else on a piece of close by e.g. using conductive yarn in between.
Before I leave next week for a 3 weeks holiday I made some Eagle schematics board layouts that I will etch when I am back.
One is a little board for external power supplies e.g. for powering the thermochromic material.
Another one is a basic board layout in case we decide to use the ATmega8 directly with an ISP programmer instead of using the bootloader.
Still we have to attach controllers to fabric in a reliable and nice-looking connection. A very nice technique by Leah Buechley (http://www.cs.colorado.edu/~buechley/engineering/fabric_PCB.html) who irons laser-cut fabric pcbs on fabric exists. Unfortunately we do not have a laser cutter. As we will stick (for this time) to regular etched pcbs we only have to connect the output pins to fabric so we can use a very quick and dirty variation. I partly cut out stripes stick the pins through from the other side and glue them together. Now I can sew to the textile databus.
As the bootloader solution of Arduino proved as problematic with young children I tested several different solutions. One is to use a cheap serial programmer to program Arduino via ISP programming. Unfortunatly Arduino relies on uisp that does not support newer version of the sdk500 firmware or usb programmer that is why I could not use the Atmel original hadrware. I used an avr910 and changed the preferences.txt and set upload.erase=true, upload.verify=true and serial.download_rate=115200 as written on the Arduino website. Also upload.programmer had to be set to avr910. A crucial point is (especially when using an usb-serial adapter) to set the Comport number between 1 and 4. Using the external programmer we could simplify the board further.
Arduino uses the 6-pin ISP while the programmer (if you buy a ready-made one) uses 10-pin – you need an adapter.
After checking and discussing the observations of our workshop we have the most important problems to fix on the hardware as the following:
The first problem is not easy to solve. The Arduino bootloader system work but it is not very easy to press the buttons at the right moment. Therefore we experiment with other solutions: using regular programmers to upload the sketches. The cheap parallel programmer proved as an unstable solution therefore it is no need to explore it further. It works but we somtimes had to erease the chip a couple of times tu brun new programs to it.
Also parallel interfaces are not found anymore on newer notebooks. We tried to use the SDK500 directly from Arduino but UISP seems to have a problem when the SDK500 has Firmware from 2.0 on. UISP also cannot work with USB programmers as the MKII. Our last hope to work with UISP is a cheap serial programmer we can get here.
To fix the cables in a more stable way we can use pin connectors with cables soldered to them, we will also try out various connection systems on the market as it is a lot of work to make the connections manually.
To ease the circuits with resistors and actuators we wanted to but the resistors and actuators on fabric and having color coded connection to the controller. I just finished to make prototypes to verify the circuits. Here are the schemes for switch, sensor and led.
And that is how a patch could look (only from the technical point of view )
