Studio Contrechoc

design & textile & technology entries

Monthly Archives: July 2015

Discharging Victory over the Sun

Experimenting with the possibilities of Victory over the Sun, an unexpected paradox presented itself: gathering energy is not too dificult, but getting rid of this energy (for starting a new game) is not simple.

In the test version with a supercap of 1F a simple short cut was used. But in version 2 with a double supercap of 10F this seemed throwing away a lot of energy. And since the energy is the theme of this silhouet, just throwing it away seems not right.

So looking around for ways to use this energy the first idea was feeding it back into the lipo. But charging a lipo is a slow process. You don’t want to wait too long to start a new game. And also charging the battery that is running the system is … probably asking for problems.

Discharging by powering a ventilator is possible but making wind is not fitting in this silhouet. So the LED’s of the hacked Ljusa were chosen. The back of the silhouet already had lasercutted patterns. Inserting the LED’s and using a aluminum foil to make an inside reflecting surface gives a nice reward for all the work during the game. Since the supercaps are discharging the light effect are dimming. Because not only Ljusa bright LED’s were used but also red bicycle LED’s the light effect change because of the voltage drop.

The voltage drops from 5V to … 1V, so a MCP1702-3002 voltage regulator was used, limiting the voltage for the LED’s to 3V. This MCP is better than the voltage delimiter LD33V because this last one takes about 1V for itself, which makes discharging the low volts even more difficult.

Getting rid of the last volts is not solved yet. Discharging properly is not as easy as harvesting energy.


Light effect after winning the game.





Presentation Version of Victory over the Sun

During the coming e-textile summercamp there will be an exhibition displaying work of all the participants. For the Victory over the Sun project, a game on a wearable between a hand crank and a solar cell this means making a special presentation version, because the exhibition will be displayed in a closed space. No sunlight to play the game.

In fact wearable projects always needs one or several presentation versions.

The two lines of LED’s on the front will be all lit. Normally only two LED’s are indicating the current game situation. From time to time there will be a simulated game between left and right (hand crank and solar cell). That way the silhouet will be “alive” and showing its potential even without players.

vs1   front   vs7    back (if discharging)

The electronics in the perspex casings at the left side will be lit by special bright LED’s, white, inside a kind of small shade. From the top of theperspex the lasercutted text will be nicely visible. The “scary” electronics will be a bit in the dark.

vs2    vs3 right side

In preparation is the next version in this project. Flexible solar cells will be used bent over the shoulders. These cells produce 1.5V each, and the game needs 5V, so another LTC3105 will be inserted. This chip boosts the voltage to 5V and can keep the most efficient load value (MPPT).

The cells of this newest version will be on display too:


The flexible solar cells can be bend to the shape of the shoulders. The LTC chip delivers 5.2V even when the Sun is weak. Compare this to the first version:


The big LED’s are nice but the light is invisible in the Sun. But of course in the latest version the bright LED’s are blinding inside.

Linking the 2015 Swatch

After the knitting of the swatch, two sides had to be linked on a circular linker. It saved time to attach 4 or 5 swatches at the same time. So the swatches are draped around the linker.


After linking two sides, one side remained open for inserting the magic. One layer of plastic and one layer of paper, — both insulators — with aluminum foil at the back connected to a rectifier bridge can make a LED flash when you knock on the two layers.


The two layers had to be inserted into the swatch. The polyesther threads will help the tribo electric effect a little bit (hopefully :-).

After inserting the 30 double layers the second linking closed the swatch. A bit of caring for some stray wires and the production is finished.

Knitting the 2015 Swatch

At the coming e-textile summercamp the Swatches will be exchanged. The Swatch is a sample of small size showing some aspect of a combination of textiles and electronics. A group of e-textile designers willing to put a lot of work into this exchange all make 30 samples and these samples will be distributed at our meeting in Paillard, France.

Making a prototype is easy. Normally there are 3 – 5 versions necessary to have a finalized version which is presentable. But than making 30 copies is another business. You have to organize all the needed components (most of the time you have “some”, but not 30 and then find the same things like the knitting yarn, or the same conductive thread is sometimes even impossible!).

And e-textile designers are experimenters, so we like to change and always look for possible improvements. So making 30 identical copies is … stress!

In my production time there are three phases: the first phase is slow, because I really have to start the production, make it a bit “faster”, modular, more efficient. Then all stages are getting into my system and production is started. But in the last phase I have to be careful to stay concentrated, I get careless start thinking of other projects, and am likely to make stupid mistakes.

My swatch, after making the first prototype, is now divided into three production events:

knitting: knitting the envelop

electronics: making the tribo electric “battery” and connecting the rectifier bridge and the LED

linking: putting knitting and electronics together and close the envelop by linking.

These three production phases ask for different types of concentration. With the knitting the knitting machine – laptop combination must be working impeccably. I had a problem with the board (lobotomy of the KH-940). What was wrong with the board? In the end, after checking all the connections of this fragile board, it was the USB cable! Replacing the cable solved all connection problems. Who doubts his USB cable???? In this knitting phase eventually during production I make all possible mistakes. Forgetting the weights, reversing the cast of order, breaking threads, etc, etc, etc. With machine knitting you can make a lot of mistakes indeed!

The electronics are reduced, but still this can go wrong: in my first sample after linking the knitting (closing the envelop) a wire got detached. Good for the production: make sure the wires are very very very well connected, because the knitting will not facilitate soldering inside!

The linking can be done by hand, but as a hand stitcher it would take me another week…so a linker machine is used. Of course arriving at this linker at school it is out of production. First I had to repair it. But then things go smooth.


The 30 copies knitted, not linked yet.

Description of this swatch can be found here:

All coming swatches can be seen here:

E-textile summercamp 2015:


Knitted at the KH-940

Screen Shot 2015-07-05 at 08.16.49

Knitting Pattern, for lace knit.