Tag Archive | wearables

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?