Tag Archive | soft circuit

Stitching LED’s in T-Shirts

People often want to incorporate LED’s in their t-shirts.  However, stretch fabric doesn’t work well for circuits because it stretches while the conductive thread stays taught.  You end up with broken thread and also some pretty nasty looking stitches, even if you use an invisible stitch.  A good friend of mine approached me about incorporating an LED into her t-shirt, because it was highly appropriate — the logo on the shirt was for “The LightRoom”, a photography co-op.   So, rather than lecturing my friend on the negatives of Jersey fabric, I decided to do a work-around.  First, I tacked  a Lilypad Arduino battery holder with switch on the label of the shirt behind the neck area, using regular non-conductive thread.  That way there would be no stitches coming through the t-shirt fabric.  (This works if you can handle labels, if not, you could stitch a piece of fabric label style on the collar and still place the battery holder there.)

Batt Holder

Then, I fed some conductive thread in my needle and started with one of the positive petals on the battery holder, making sure to create multiple tight stitches like sewing a button.  Moving to the fabric of the shirt itself,  I connected to the bottom seam edge along the neckline with straight stitches, hiding in the seam until I reached the front side of the shirt.  Remember that conductive thread can short with skin contact, so I kept the stitches between the seam and the t-shirt.  Next, I picked up a piece of taupe satin seam binding, the kind often used in formal dresses to finish off a seam.  I cut a length that would fit perfectly from the point on the neck to the spot on the logo where I would incorporate the LED.  In this case, that spot would be above the letter “i”.  I tacked the corners of the seam binding near the neck of the shirt with regular non-conductive thread.

Seam Tape

After threading my needle with conductive thread, I made straight stitches joining onto the previous neckline stitching, moving directly into the satin seam binding.  Keeping in mind the problem of stitches and skin, I made my stitching on the inside of the seam binding (not on the flaps), on the part that would be touching the t-shirt fabric.  Once I reached the end, I stitched my LED in place at the positive side.  Finishing up,  I cut the thread and moved to the negative side of the LED.  With new conductive thread, I stitched loops firmly in place to hold the LED, and then moved to the satin seam binding.  Moving in parallel next to the previous stitching like a train track, I made another series of straight stitches leading back up to the neckline, being careful not to get stitches too close for fear of shorts.  This time, instead of stitching on the lower seam on the neckline, I moved straight up into the upper seam.  Like before, I made straight stitches under the edge, making sure to keep them between layers of fabric so they would not hit the skin.  Following the same curve of the neckline, I made my way to the battery holder’s negative petal and stitched another series of tight loops to secure the petal in place.  As with any electronic wearable project, I finished my knots with clear nail polish to prevent unraveling.  As a finishing touch, I used regular non-conductive thread to stitch the flaps of the satin seam binding together, so they wouldn’t shift open under the shirt.  So, in essence, this was like a mini bra strap inside the shirt that was only connected at the neckline and the LED.

Here’s the finished shirt powered on and my content friend!

Shirt FinishedAnnarita Model


Costume with LED’s

After I returned home from the workshop in TN, I was approached by a theater director to infuse some lights into a costume.  This wasn’t just any costume, it was a costume for a drag show called “Star Whores”.  What could be more fun than a sci-fi musical extravaganza with cross dressing?  I soon was matched up with the actor, Kevin, who had created a nicely draped, and somewhat flashy winged garment.    My idea was to add LED lightboards rows into the wings.

LED Pattern I originally imagined three rows of lights, but once I had the costume in hand, it was obvious that would have to be changed.  The last strip of fabric on the wings was barely attached, which meant there would be no safe way to have two rows of conductive stitching without the threads touching and shorting.  It could be done, but it would take some alteration using seam binding or additional fabric.  Not wanting to vary the costume design, I decided on having two rows of LED’s on each wing.  The main question then became, “what color LED’s?”.  After some discussion with the director and the actor, it was decided that pink and blue would be a fun combination — especially since the show played with gender.  I set to work using the stickers from SparkFun’s Lilypad line to represent the layout of the various parts.  At first I thought these stickers were for beginners, but as I have gotten more involved with design, I’m finding them to be extremely helpful for seeing the layout and path of the threads.

Costume DetailOnce I had the parts in their best places, I marked the locations with pins to make it easier to work.  I started by stitching the Lilypad Simple Snap board on the back center of the wings.  I had decided the theater company could borrow my Lilypad controller for the performance, so really they only had to deal with the expense of the snap base, LED’s and thread.  Once the base was in place, then I started working on the rows of LED’s on the wings.  The glittery fabric and rhinestone looking trim set off a small alarm in my head.  They looked metallic, so it was important that I get my multimeter out.  There was just a hint of conductivity in the trim, so I kept the stitching as far from those areas as possible.  In general, using conductive thread on stretch fabric is not the best situation.  The thread has no stretch, so you have to be careful to use the technique only on areas that won’t be stretched.  Luckily the wings on this costume were one of those areas!

I only had three days to get everything complete, so there were definitely some late nights involved.  I would use the multimeter as I finished each LED to make sure that I had continuity.  Once I was done a row, I would then attach the microcontroller and run a test to be sure all lights were lit.  One of the main problems with doing any LED project is calculating the power for the LED’s.  I even checked with an engineer friend on this matter, and there really is no good way to calculate this figure since there are so many variables — different colors of LED’s, different distances of thread etc.  In the end, you just have to test your circuit ahead of time and then place it on the outfit.  In my case, it was hard to even guess the thread lengths, so I just had to stitch and keep testing.  Luckily the lights were holding up well to the built in LiPo battery.

As with all projects there was some last minute drama.  I had wanted to include a switch on the top of the left wing, so the actor could initiate the lighting effect.  For some reason, the switch would not work, or when it would work, it would only trigger one or two of the rows.  I called my engineer friend, Brooks.  She was actually at an airport and happened to have Lilypad Arduino equipment with her since she was going to be teaching a class soon.  We had the funniest phone call together — me talking her through my circuit and her trying to mimic the LED’s on her microcontroller.  In the end, we finally reached the conclusion that there was too much resistance with the length of thread leading to the switch.  The actor had very limited movement with the costume, and there was no way to get the switch closer.  So, the switch had to be left out.  Wings LitThe final thing left to do was the code for the LED’s — it’s really the moment you wait for.  After testing various patterns, I decided the lights should really be more like the birdlike character it represented.   I had the top rows and bottom rows turn on and off much like breathing.   It’s one thing when you know you like something, but the real test is seeing audience reaction.

I remember being nervous the night of the show.  As a past actress, I know the jitters you get and the excitement that spreads through your fellow cast members.  At the hour of the show, the venue was packed.  The director had the audience stoked with some pre-show sci-fi music.  People were singing and they were expecting outrageous.  The moment the actor came out was really divine.  He stepped right into the main spot, and the LED’s were twinkling like magic.  People were actually smiling and pointing.  Some of them were trying to peer around as if trying to figure out how the lights work.  I think people expected to see wires and plugs like Christmas lights.  However, that is the beauty of wearable electronics.  When done properly, they work with the outfit and blend.  Even the microcontroller on the back of this outfit blended amongst the glitter, sparkles and forgiving sci-fi theme.  And when all was over, I let the actor know that he could borrow the controller, just in case he felt like bringing his character back to life for an evening.  No one wants magic to stop.  Either do I.  I wonder what will be next?

Crafting Electricity Workshop

NASA Space Apps proved to be more important than I ever thought — it helped me to win an award from Systers, a female tech organization.  The award is called “Pass-It-On”, and is geared to help women on the tech path, with the understanding that they will give back in some way.  My award was for a class called Crafting Electricity at Shakerag Workshops in TN.  It was already amazing to be winning an award, but there was yet another surprise.  As I checked my email in the airport, I discovered that the woman in Florida that assisted me on the Orbit Skirt for NASA, Brooks Zurn, was also signed up for this workshop!  In fact, one of us was over the amount of seats that were available in the class, and had they not allowed one extra seat, one of us would have been eliminated.  I guess Brooks and I were just meant to be. 🙂  Back to the story…  Leah Buechley, my fave tech artist and inventor of the Lilypad Arduino, was the teacher.  It took a while for me to get used to being in the same room with a rock star, but once the fog wore off, I was able to concentrate on paper circuits.  I was doing really well working with the copper tape, but once we got to surface-mount LED’s, well, that was another story.  Leah had given us an assignment to make a little story called “Boy Meets Girl”.  Well, it took me a whole day just to get one LED soldered correctly, granted they are just a bit bigger than a grain of rice.  So, my story ended up being rather short and sweet.  Our entire class struggled in some way or form and we all ended up going to bed about 3:00 AM! LED StoryThe one thing that I did spend quite a bit of time on was the power source.  While most people in the class chose to use a button cell battery on the corner of the page to connect to their circuit, I invented a conductive bookmark.  The top had copper tape, while the bottom had a battery and conductive thread tassel.  When the bookmark is held over the open bracket of the circuit, it completes it.  The beauty of this method is that you can create a whole book and just use the bookmark to activate each page.  I’m sure I will make a prettier version and one day use it for someone’s scrapbook — that’s the beauty of having a week long course to tinker. Once we had gotten our feet wet with paper circuits, we moved onto combining a microcontroller into our work.  Since we were working with Leah, it was only appropriate that we use the Lilypad Arduino.  The model she chose for our class was a newer once which had a self contained LiPo battery, as well as a removable snap base.  I was so excited by the base, because microcontrollers are expensive, and this meant you could have multiple projects that all share one microcontroller.  It was pure genius.  We began with a simple program to light up another surface mount LED, and this time we used conductive paint.  I really enjoyed the conductive paint because it is an easy way to make connections without solder.  This means it really lends itself to classes with young people.  Lilypad PaperAnother nice feature in this particular circuit is the bendable flap with the copper tape.  Throughout the week we found ourselves experimenting with switches.  The green LED on the Lilypad shows the device being on.  The surface mount LED is the tiny yellowish speck on the left side of the painted circuit.  I couldn’t take the photo with it on because it is actually extremely bright and blows out the picture.  They make great light sources for Halloween masks, artwork and gift cards. Since we had connected the ideas of circuits, programming and craft materials, it was time to embark on a project.  Leah happened to demonstrate a piano program that used capacitive sense.  You may remember from one of my earlier posts, that this was the exact type of program that I needed to make my musical spider’s web.  It looked  like my opportunity had arrived.  I started with a sketch and then strung my first model on some chair legs in the studio.  I knew things would be challenging,  because I only had conductive thread, not conductive yarn on hand.  The thread would occasionally break and I would have to start hand stitching onto the Arduino  as I was hanging it.  Gradually I got the pressure right and it started to resemble something that “Charlotte” would have been proud of.  The inside lobby of the building was my chosen spot for the web since it was scheduled to rain the next day.  The architecture was very modern and actually very similar in shape to tree branches.  The best part is that the metal rods were painted, which meant they were no longer conductive.  That was one short I didn’t have to worry about, however,  there were others.  I learned how to felt from a fellow classmate and made a cute hatch to hide the Lilypad Arduino.  The felt looked great, but it attracted every little piece of conductive thread that I had snipped.  One of my trickiest shorts ended up being a 1/2″ thread lodged on some stitching.  It’s all part of the learning process, and to be honest, it looked so cool that I never minded a single minute troubleshooting.  The finished web was playable on the spokes, while the center swirled string was merely decorative.  Incidentally, the center string came from another group at Shakerag that was working on natural dye methods.  There was much cross pollination between the classes during our stay, which merely added to the inventiveness of the projects.  Check out the finished web video.


The talent in our class included  filmmakers, painters, woodworkers, felters, papermakers and graphic artists.  It was really great seeing so many possibilities combining microcontrollers and circuits with these materials.  I leave  you with more examples from our Crafting Electricity class.  In the meantime, I’m already contemplating classes I’ll be doing at my local tech art org — The Hacktory.  I believe the first one will be doing paper pop up circuit cards for the holidays with a young woman that was attending Shakerag from Philadelphia.  I’m also contemplating programmable pumpkins for Halloween — light up LED eyes and spooky sounds.  It looks like my tech art teaching has begun.



Testing CapSense

Although Arduino has many fun programs in its library, I was in search of something a little more touchy-feely.  To be more specific, something that is touch sensitive.  I found out that someone had written a CapSense program for Arduino here.  This program gives the user the ability to create an object that when touched, will trigger an event.  Think of those lamps that when you touch the base, they act as a switch adjusting the brightness of the lamp or turning it on/off.  Sounds useful, right?  So, I set about uploading the program and doing a test.

The Lilypad Arduino has what is called pins around the outside circle.  That is a very electronic term, but basically they are the little holes you see on the edges that allow you to attach parts.  I’m just going to call them petals because the whole thing looks like a flower anyway.  Leah has a great diagram here to show what these petals are called.  Notice that some of them are marked “D” and some of them are marked “A” — this means Digital vs. Analog.  More on that when it is appropriate.

The way this capacitive sensing works is that it measures the electrical capacitance of skin as it touches or nears a pin.  In fact, it is similar to what a lie detector test is doing when you are hooked up — except the detector is looking more at changes from emotional stimuli rather than touch vs. no touch.  For my project, all I need is the second.  It takes two pins for each touch sensitive area, so I first had to connect a 1 M resistor between two of the petals that are used in the program.  I didn’t want to solder or use conductive thread since this was just an experiment, so I utilized a breadboard (not to be mistaken for my cutting board).  A breadboard allows you to connect various parts of a circuit and just use alligator clips to connect to your project for testing.  Once I had the resistor in place, then I needed something to act as the conductive metal to “touch” in order to trigger change in the program.  Some people make simple piano keys using some copper tape, but I decided to use conductive yarn.

So, here you have the setup, the alligator clips lead to the breadboard with the resistor and then there is the conductive yarn ready to be touched.  Remember the power is actually coming from the USB connector attached to my PC.  There’s one other thing that I want to point out here, I’m also using a circular yellow piece of craft foam as a coaster underneath the Lilypad.  This coaster allows you to clip things on without the whole thing sliding around — quite handy.  So, now it’s time to do the test.  First I have to turn on the Arduino monitor to allow me to see live data flowing, which  in this case will be numeric values for the petals in operation.  This particular CapSense sample program uses three possible touch sensitive areas, but I’ve only hooked up one for the test.  So, that means there will be three columns of values with only one column actually activated.  Let’s see what happens when I touch the yarn…

As you can see in the first column, there is a string of relatively low numbers which then shoot up at line 3907.  That is where I touched the yarn — success!  Notice they drop down again a few lines later once I’ve released the yarn.  This is exactly what I was hoping for.  So, in my case, I want the project to sense when I’ve touched yarn, in order to trigger a sound.  However, I won’t be able to get to that until I’ve done another round of testing with CapSense with more inputs.  I would really like to figure out how to have six to eight touchable areas instead of just three.  That will probably take some minor code hacking, but I’m not worried as it’s already been a great day.  Now I have to plan a visit to Radio Shack in order to get more 1M resistors.  I used to work at Radio Shack a very long time ago, and it’s still funny that I remember codes for some of the part items.  So geeky.  Sayonara!

Hello Lilypad Arduino!

After tinkering with some stitchable LED’s or soft circuits, I decided to move on to something a bit more serious — the Lilypad Arduino.  This beautiful microcontroller was designed to be used in textile arts by one of my faves, Leah Buechley.  Notice the red gizmo?  That device allows it to connect by USB to a computer to utilize a software called Arduino, which is C based for fellow geeks.  Arduino has many programs stored in a library, and the one you see running now is called “blink”.  It’s making the LED turn on and off.  Yes, this is exciting stuff!  As long as the unit receives power, the program is stored.  That means you are free to stitch this baby into a dress sans cord.  However, for my first project, I have something different in mind.  Like the geisha I am, I do not wish to reveal all my knowledge at once.  So, you will have to be patient as I unravel the threads (hint).  Notice the wood slab?  It’s important to work with electronics on a surface that will not create a static charge, and since I enjoy cooking, I decided to use an old cutting board.  I think it’s a nice female touch.