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Lilypatch: Quick Laser Cut Soft Circuit Breakout

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Rapidly make your Attinies sewable! The Lilypatch is a quick and easy way to get many of the advantages of Lilypad-style sewable arduinos without a lot of the cost or effort.

In short, it is a piece of felt, laminated with a piece of conductive lycra that is then laser-cut into a solder-free prototyping platform (with a built-in battery holder!). To build and use it just needs 3 steps:

  1. Glue felt to lycra and laser-cut
  2. Punch DIP socket into Lilypatch, bend pins and remove backing (no soldering)
  3. Flip over pads (if needed) and sew to attach to devices or clothing.

In this instructable, I'll go into a bit more depth to help guide you along, and also hopefully to get all your ideas about how to improve, what I hope could be a very useful "patch." This one is formatted to work specifically with Arduino ATTINY85's, but with advice from you people out there, we could make a whole ecosystems of cheap, simple circuit boards floating freely around the internet for other microcontrollers or electronics. I'm sure lots of people have made very similar things before, and can give all sorts of great feedback. This project was created with very specific needs in mind, but hopefully releasing this design out can help out others too!

Why was this created?

In my PhD research (digitalnaturalism.org), I go out to far out of the way places, like the jungles of Panama or Singapore/Malaysia, and try to teach workshops for creating digital devices to interact with animals in their natural environment. In some of my upcoming trips, I am hoping to actually run some hiking hackathons where we will be out in the woods living for several days or weeks. This poses many design challenges, primarily was how to do electronics out in environments without wall electricity or soldering irons. Soft-circuitry was a good choice, because we can just sew connections together, but for a not-well funded researcher like myself, buying and giving away a bunch of Lilypads can get really expensive. The Gemma is the cheapest sewable platform (http://www.adafruit.com/products/1222), but $8 +shipping, makes it still too expensive to not want to ask for them back from my participants. Also with a cheaper solution, I can build lots of different things and not have to worry about harvesting their boards later. This is what got me into using ATTinies in the first place (they are dirt cheap and do most the stuff I want, and they're the chip already in the Gemma). Their problem is that they can be hard to use without soldering them

Thus I wanted to re-create the capabilities of the Gemma but in a cheaper, more disposable way. So I set up the following design goals for myself:

  1. Cheap
    1. The price to beat is $8 for the Gemma, and Ideally I want to keep it around 1-2 dollars, letting me supply 50-100 people in workshops with a budget of just $100.
    2. The material cost of one of these lilypatches with an attiny in them is just around $1.00-$1.40 (felt, lycra, attiny, thread).
  2. Little Pre-manufacturing
    1. I wanted to figure out a 1-step process to rapidly make something I could take and put together however I wanted out in the field.
    2. Manufacturing during a trip is fine (there’s plenty of time for tinkering late at night while camping, but anything that needs exotic tools like laser cutters should be taken care of previously).
    3. Another regard was that I wanted to use this to teach electronics, so by not making it too complicated, people could use it as a platform to learn some basics on.
  3. Minimal Exotic Materials
    1. I wanted to limit myself to using only 1 non-conventional material. In this case this was the conductive lycra.
    2. I’ve gone through dozens of ideas trying to figure out how to do this, (eg. mix shapelock and wires, make conductive glue and run leads to conductive fabric, …etc).
  4. Versatile application
    1. The pads can be sewn to, gator-clipped to, folded over and stapled together, or used as touch-pads themselves.
    2. The pads stick out so that they can be flipped over for sewing on either side when attached to a garment or other device.
    3. I went through all sorts of geometry problems figuring out balances between making good contacts, making the backing peel easily, determining how to lock the pin legs to the right leads, while also trying to balance how this thing could be used. This hybrid, flip-if-you-want method with a battery pouch seemed to be my best option (after lots of personal iterations!)
    4. This design is also left open to lots of simple techniques that could make it a lot more robust (like if you aren't in the jungle, use some hot glue to seal the connections better!), though these aren't 100% necessary for simple projects.

What can it be used for?

All kinds of stuff! In theory anything you can do with an Attiny85 (which is a lot!). For many projects at home or in the lab, you might want to do some good old soldering for really good firm connections, but if you want to get started on an idea quick, and especially with soft-circuits stuff anyway, this might be a good option for you.

Also if you need to do some projects but get sick of sitting at the soldering iron, this can be a kind of fun activity, sewing together these different parts, that you can do while watching a movie or something.

I give three examples at the end of this instructable, a simple flashing costume, a plush, light-up cell model, and a device for monitoring where your pet tortoise may have run off to!

Help and Inspirations

Tom Jenkins, an awesome auteur of tinkering platforms (http://thomasjenkins.net/), helped me think thought this thing a lot

HOWTOGETWHATYOUWANT (http://www.kobakant.at/DIY/), as with most things soft-circuitry-related, the folks over at kobakant have compiled many great resources and ideas. For instance, the idea of making a conductive battery pouch like this comes straight from them: http://www.kobakant.at/DIY/?p=4432

Update: I just saw this other similar project they have http://www.kobakant.at/DIY/?p=2672 where they make a breakout board from laser cut fabric, but they also use somewhat specialized things like fabric fusing and pourable acrylic or soldering. This design I'm presenting here hopes to accomplish a very similar goal (in perhaps not as robust ways) with more limited materials.

 
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Wow, this is a really great idea. I see many light up costumes in my future!

Thanks! One of the workshops I run has people make their own light-up firefly costumes. Now it'll be even easier to teach! http://dtc-wsuv.org/wp/mla14-critical-making/2014/01/04/living-lightning/

Cool!

jbrawner6 months ago
I love instructables like this they sound very interesting and fun to build. but the problem with this one and with others that I read about on this website are the use of these laser cutting machines. this is not a shot at anybody, I'm just trying to say that in some places people don't have access to technology like this. Are there alternatives to some of these instructables that require the use of the laser cutting machines? The same complaint goes for that require 3 d printers and CNC machines. I am sure that access to these devices are fairly easy for somebody enrolled in a university or work at a high end shop and can take advantage of those available resources but I don't believe everybody has access to perks like that. I am quite sure most peoples motivation for going to instructables websites are to learn how to make things themselves and to save money. however if we have to pay a company to make something for us using those technologies it doesn't quite bring the cost down.
blorgggg (author)  jbrawner6 months ago
Totally agree. People far too often act like laser cutting stuff is a simple luxury anyone can afford. But the truth is that these are still luxury specialty items to priveledged people who are in a university environment (or get stupid lucky and win an instructable competition).

The nice thing about laser cutters though is that many more people do have cheaper access to them than more sophisticated things like CNC PCB mills and pick and place machines. And they tend to be a lot less sophisticated to use than many 3D printers, so even novices can quickly go up to one (if they have access) and manipulate or change designs to how they see fit.

With lots of people doing DIY laser cutters the cost is also really coming down, and hopefully they will be a cheap common tool you could find at Home depot like many other tools like a table-saw.

As always we are caught in the middle of hidden privilege and common reality, and the automation of machines replacing humans in tasks, and the abilities of humans to augment tasks.
blorgggg (author) 6 months ago

Does anyone know if you can cut the foam sheets they sell at Michael's? I can't find what they are actually made of:

http://www.michaels.com/Creatology%E2%84%A2-Foam-S...

I think they would be good to use as well for this application instead of the felt.

blorgggg (author)  blorgggg6 months ago

Just tested it out, works great! No obviously toxic fumes came out, and the thing is nicely sewable and durable!

blorgggg (author)  blorgggg6 months ago

I think it might be EVA, which i think you can safely cut on a laser cutter

diy_bloke6 months ago

very nice idea. I had to laugh though at 'the jungles of Singapore' kind of an urban jungle with a few patches of green in between :-D

blorgggg (author)  diy_bloke6 months ago

Hahah yeah! I am actually going there for the first time this sunday to join some researchers in the field. Apparently we are going to some of those little green patches but also further out into malaysia.

try sungei buleh. still crocodiles there

kschroeter6 months ago

You're research sounds really cool! Good luck

blorgggg (author)  kschroeter6 months ago

Thanks!

pcola6 months ago
were have you find this laser ? i have a mini cnc diy so i would like to apply an opportune laser to cut things like this...
blorgggg (author)  pcola6 months ago

I think there are a good amount of DIY Laser Cutter instructables on here. Maybe they will have some answers for you!

logwet6 months ago

This is really cool! Well done.

Om-Vaghela6 months ago
good work.....