The theory behind speaker operation is pretty simple. There’s a coil that is attached to some type of diaphragm and a permanent magnet. When electrical signals pass through the coil a magnetic field is generated, and that field’s interaction with the permanent magnet causes the diaphragm to vibrate and create sound. But we’ve always assumed that the vibrating material must be stretched tight for this to work. [Hannah Perner-Wilson] proved us wrong by making this speaker out of fabric. It uses conductive tape as the coil on a heavy piece of canvas. The permanent magnet is resting on a table and for the demonstration the fabric is just laid on top.
Check out the video after the break to hear the sounds generated by this device as well as a design that uses conductive thread instead of tape. This gets us wondering if what we’re hearing is the result of the magnet vibrating against the tabletop? Let us know your thoughts, and if you’ve got any information about the paper-backed circuit (seen at 0:04 into the video) driving the speakers we’d love to hear about that too.
[Lenore] added a bit of customization to her office window hangings by fitting roller curtains with custom printed fabric. The treatment seen above is a $20 Enje roller blind from Ikea but that logo is all Evil Mad Science. The weight at the bottom of the fabric uses a friction-fit plastic insert that can be stapled onto new material. Some fusible tape was ironed onto the sides to finish those edges, and the roller at the top has strong adhesive that remains for a second use after peeling off the original material.
A fabric printer was used to produce this rendition of shades. But we’d like to see some conductive thread added for a fabric-based display that can be rolled up when not in use.
If you’re into embedded clothing this stroke sensor is for you. As demonstrated in the video after the break, stroking the threads in a particular direction will create a circuit that senses and, in this case, turns on an LED. The concept uses two conductive buses on the back of a piece of neoprene. Conductive and non-conductive threads are then added for a furry or bristly finish. When stroked perpendicular to the power buses the conductive threads come together and form a circuit.
For some reason this just seems a bit creepy to us but perhaps that’s only because we haven’t come up with the right application for the technology. We’re pretty sure that a sweatshirt with an LED marquee and a “hairy” back that you stroke to illuminate is the wrong application.
The device consists of a positive bus of conductive thread sewn onto a regular piece of fabric. A second piece of fabric separates this from a ground plane made of conductive fabric. The LED leads are then bent into a spiral and can easily be wrapped around the appropriate part of the conductor.
We’re happy to see this creative design coming from a hacker that frequents a hackerspace; Pumping Station One in Chicago. This would be a wonderful application for banners or flags at hackerspace events.
We don’t want your brains to explode, so just trust us that this is a truly one sided circuit. Being a mobius strip means that this circuit has uber geek bragging rights. Beware, your friends who have never heard of a mobius strip will argue until they are blue in the face that there are two sides to it. The circuit they chose was fairly appropriate, an LED “chaser”.
[mikamika] has put together a great tutorial on how to build this musical shirt. The whole process is covered, from taking apart the toy keyboard to laying out the circuit and creating the fabric switches. He used the same method as [plusea] for the fabric buttons and conductive thread for most of the connections. It seems as though he has actually taken [plusea]’s wearable shirt project and added some polish. His looks good enough, he might even be able to make it through an airport.