We love doing electronics projects. We love teaching kids and adults how to build awesome electronics projects.
For years now we've found that there are really only two ways doing DIY electronics:
- Buy a very expensive kit
- Use inexpensive off the shelf parts that are hard to use.
There didn't appear to be any middle ground between "easy to use" and "expensive." So we created our own open source system: CRAZY CIRCUITS!
At the heart of this project is the Crazy Circuits Touch Board. The Touch Board is built around a Teensy LC microcontroller and features capacative touch inputs. Any conductive material, from a cup of water to a potato can be turned into a touch sensor, no grounding necessary.
Here we turn the word NASA into a touch sensitive switch with conductive thread. It triggers the LED stars twinkle randomly. Ooo, shiny.
Step 1: Video and Materials
For those who prefer visuals, check out the video above.
Before you begin gather your materials and tools. For this project you will need:
- NASA T-shirt
- Space Shuttle patch
- Spare fabric for pocket
- 3 AAA battery pack with switch.
- 1 Crazy Circuits screw terminal
- Crazy Circuits touch arduino board
- 5 Crazy circuit 5mm LEDs
- Conductive thread
- Black thread
- Needles, one with a large eye for the conductive thread.
- Sewing machine for pocket and zig zag stitching.
- Iron and ironing board
- Pins to hold things together.
Step 2: Sewing NASA
Start sewing the word NASA by hand with conductive thread.
First I traced around the edge of the letters with conductive thread, then I filled them in with diagonal lines. You may follow any pattern you like. We recommend that the distance between any two lines of thread be less than a finger width.
The most important part is to make sure everything is connected to ensure good electrical conductivity. When you reach the end of a length of conductive thread while sewing the letters, follow these steps:
- Tie a knot as usual on the back of the project.
- Thread the needle with a new length of thread and tie a knot on the end.
- Starting on the back, tie the end of the NEW length of thread to the end of the previous thread. Make sure this knot is good and tight.
- Continue sewing as usual.
Step 3: Attaching LED Stars
Next attach the LEDs to the shirt over the stars. Do this with NON-conductive thread.
Sew through each hole several times, going around the edge of the board. Tie a knot on the back.
Step 4: Touch Board and Ground
Attaching the Crazy Circuits Touch Board
Next attach the touch board to the lower right hand side (or left if you are left handed).
Have the USB connector pointing UP. Make sure it is up at least an inch above the hem of the shirt so there is room to sew the pocket around it.
Sew through several holes with NON-conductive thread, making sure the board is securely in place.
Stitching the ground conductive thread
Next we start attaching the board to the LEDs with conductive thread. Started with the ground (negative, white) pin. Use large stitches which keep the thread mostly on the top. This has two advantages:
- Can see the circuit pattern on front and follow where things are connected
- Makes it easier to cross under and not create a short circuit.
Start at the ground pin on the touch board and stitch up and around the Nasa symbol, connecting to one negative (white) hole on each of the LEDs.
Be careful not to stretch the T-shirt when hand stitching the conductive thread lines. T-shirt material is very flexible and if you stretch it too much the shirt will end up looking lumpy and uneven.
When attaching the end of the conductive thread to a board, follow these steps to ensure a good electrical connection.
- From the back side, come up through the board hole
- Wrap thread around edge of board and come back up through the hole. Do NOT go through the fabric.
- Again wrap thread around edge of board, this time go THROUGH the fabric.
- Repeat steps 1-3 a couple more times.
Step 5: Connecting the LED's +
Connecting all the components
To minimize jumping conductive thread lines, start sewing connections from the center out.
First connect the "always on" pin #23 to the shuttle LED positive side.
Next the touch sensitive pin #15 to the conductive thread around the word NASA. I followed the line of the NASA red swoosh to help it blend in.
The LEDs over the stars are programmed to twinkle in a semi-random pattern, so it doesn't matter what order they are connected. They are pins 3,4,9 and 10. I started at the top LED + pin #3 and worked my way down and out, following the previous lines and contour of the NASA logo to the LED positive (dark) sides.
You may have to cross under the lines in several places. When jumping lines sew under the conductive thread in the middle of a large stitch. Come back up to the front of the shirt well away from the conductive thread on the top. This will avoid short circuiting the lines.
Step 6: Zig Zag Stitching
All those big stitches and parallel lines can bend and touch each other, shorting out the electricity in them and keeping the shirt from working properly.
To prevent this, use your sewing machine and non-conductive thread to sew a large zig-zag stitch over all the conductive thread. Use clear thread if you have it, but black will also work.
DO NOT sew over any of the components, this will break your sewing needle and ruin your day.
Step 7: Space Shuttle
Place the shuttle patch over the LED at the end of the NASA swoosh and hand stitch the edges to hold it in place. Our shuttle also had iron on adhesive on the back, so we pressed it with an iron to make it double good luck stuck.
Step 8: Battery Pocket
Add a pocket!
Lay out the battery pack near the touch board to determine how large your pocket should be. Remember the shirt will flex so it is ok if the pocket looks tight.
Cut a piece of fabric 1" too big on all sides.
Fold the edges over twice to hide the cut edge. Iron the edges to make them nice and crisp.
Using a sewing machine, sew the top of the pocket to itself first.
Next, pin the pocket to the shirt over the touch board. Using a straight stitch (not zig zag) sew around the two sides and bottom with the sewing machine, making sure NOT to sew over the touch board. Again, this will break the needle.
And you are done with the sewing!!!
Now insert 3 AAA batteries into the battery pack. Connect the red wire to the positive (dark) side of the screw terminal and the black wire to the negative (white) side of the terminal.
Unless you skipped ahead of us your board will not be programmed yet. So the shuttle LED may or may not come on when you flip the battery pack power on. But an LED on the touch board should light when the board is powered on. If not, switch the battery pack wires.
Now on to programming.
Step 9: Programming the Touch Board
Load the code as you would on any arduino board through the USB cord. Code is here on our github.
Once it's loaded, the shuttle LED will come on a few seconds after the battery pack is switched on. Now when the conductive thread is touched it will trigger the 4 LEDs on the stars to twinkle and pulse randomly. Geektastic!
One word of warning, we do NOT recommend wearing this shirt over bare skin. Wear an undershirt. Skin is highly conductive and will short out the circuit, stopping it from working properly.
And thanks for reading this far. Check out our other Crazy Circuit kits and projects.