LEDs for blinking clothes to be better recognized outside are fun, but i didn't like sewing very much. Therefore, i decided to use an easier approach: Iron a motive on a textile and enlight it with a leds in rivets. Therefore no sewing it required.
I use WS2812B SMD LEDS, connected with wires with a micro controller of your choice. Standard rivets eyes for textiles (8mm inner diameter) are used as a LED holder together with a 3D printed inlay (but a hand or lasercutted diffuse acrylic will work, too).
The motive is (laser-)cutted out of white poli-flex premium foil for t-shirts, which is ironed on the textile.
Step 1: 3D Printing
First print a bunch of LED holder which will hold the led within the rivet and work as a diffusor. I use basic white PLA, which is thin enough to let enough light through.
You can also cut a 8mm circle out of diffuse acrylic if you do not have a 3D printer available.
Step 2: Cut the Motive Out of Flex Foil
I used a lasercutter to cut the motive out of a poli-fley foil. The motive has to be cutted out mirrored (something i allways forget on the first run), and the transparant foil should remain uncutted. With the epilog zing 30W lasercutter i used 7% power, 100%speed and 5000 frequency.
The flower is by the way from vector flowers, jsut enlarge an image such that the 8mm rivets fits nicely.
After cutting the flex foil remove the unnecessary parts.
Step 3: Ironing
The flex foil is then arranged on the textile and with a cotton textile in between ironed on. The ironing works with highest power and pressure. While removing the upper foil after ironing check if all parts stick with the textile, otherwise iron again above this parts.
Step 4: Punch a Hole
With the rivets you get the tools for punching holes in a textile. Insert both metal parts into the holder and arrange them on the right part of the textile (The smaller 8mm diameter tool should be on the outer side for better positioning). If you have the tools on the right position, press them firmly together (alias known as punch it with a hammer).
Step 5: Insert Rivet
Thereafter, the rivet can be insertet: The higher part goes to the outer side, the lower part on the backside (with the small groove towards the textile). Again the provided toolholder is used to press everything together: A plastic anvil holds the higher part in place, while the 8mm diameter metal tool forms the rivet with a hammer blow.
Step 6: Insert LED Holder
Now the plastic diffuser can be mounted into the rivet eye: I used epoxy glue to fixate it at its place, just coat the edge of either the rivet or the holder with the glue and insert it.
Step 7: Add the LED
The WS2812B has four pins: The one with the small triangle on the top side is the ground connection (i marked it on the backside with a black dot to find the right pins after mounting). The neighboring pin is the data in connection. Diagonal opposite of ground is the VCC pin. Its neigbor is the data out, which can be connected to the next LEDs data in pin if more than one LED is used. VCC and Ground are used in parallel for all LEDs.
On this pins small wires are soldered which connect the LEDs and a microcontroller and battery pack.
Step 8: Crimp Contacts
Ok that's not really necessary: But if you have the right tools at hand you can crimp male plugs on the end of the wires for a nice connection to the micro controller. Or just solder male pinheader on it.
Step 9: Test
At the end, connect the LEDs with your favorite micro controller - the basic Arduino might be a little bit large, but there are smaller ones with the same functionality (e.g. the Wattuino Nanite is perfect for this task, or build your own one with an attiny).
For the Arduino Uno you can just install Adafruits Neopixel library and upload the basic example, then connect the VCC and Ground of the LEDs with the 5V and Ground of the Arduino. The Data Input of the first LED is connected with pin 6 of the Arduino.
(If you want to use more than the five LEDs of the example, you have to change the number of LEDs in
Adafruit_NeoPixel strip = Adafruit_NeoPixel(5, PIN, NEO_GRB + NEO_KHZ800);
Thereafter, the LEDs should start to emitt light.
Step 10: Done!
Then add a battery pack for mobile power supply (either a 5V LiPo booster or just three 1.5V AA batteries in a row) and enjoy your new shiny clothes.