Charliplexed Led E-textile Patch

April 15, 2011 by · Leave a Comment
Filed under: Electronics, Projects 

Did you bring a hack? – (Spring of 2011 -Pre Maker Faire SF Bay Area)

Answering this question was the driving motivation in getting this project underway. After seeing several Charlieplex links on hack-a-day, I decided it was high time that I give it a try myself. I wanted something I didn’t have to carry around, so a T-shirt seemed like a logical choice. I had seen some other LED based e-textiles, but didn’t want to use huge 3mm or 5mm LED’s. Surface Mount Led’s came to mind, but I was not sure how to go about soldering anything to conductive thread.

Fortunately, I ran across an article describing how to mount surface mount LEDs to fabric by way of soldering small crimp beads to each end. This provided a place to loop the conductive thread through the LED.

First, acquire crimp beads and leds:

Seccond: Assemble

Each SMT led has a silver ring attached to it.

Next I had to decide how to design and control the Charlieplex.

The first step, was a prototype circuit and layout. I really have to thank this guy [Ben] for posting helpfull information on the web. His 5×4 Charliplex display walkthrough provided me with the design I used to lay out the e-textile. I ended up taking his hand drawn schematic and using it as my t-shirt layout with minimal changes. I don’t have a printer at home, so I actually traced this schematic from a sheet of paper I placed over my monitor, and transferred that to the front and back of the fabric.

Then I added the conductive thread and components.


then I cut out a square, attached some connectors and an Arduino, and stuck it to a shirt!


Laser Beams and 555’s

March 2, 2011 by · Leave a Comment
Filed under: Electronics, Projects 

This page serves as my contest entry for the 555 timer design contest.

I have created a laser trip wire that actuates a camera. An ambient light sensor by Vishay ,  the TEMT6000 [datasheet] from Sparkfun Electronics, acts as  an NPN transistor attached to a 555 in BiStable mode. The output is sent to a logic inverter for quick visual status, then off to another 555 in Monostable configuration. The output from that 555 can be used to actuate any number of devices (Electric squirt gun, Sirens, Nerf guns, etc.), but in this example I have my camera set up in continious fire mode, as the output stayes on for several seconds. This could be used for catching a burgler (who probably wants to steal my camera), or more usefull items such as taking pictures at the end of a race.

I have a green laser for visuals, but it is probably possible to use alternate frequencys or light that are less visible to the human eye.


laser ——-Light sensor(npn) ~555 bistable> inverter logic chips and Status leds> 555 monostable >transistor (npn)-relay >camera trigger > CLICK!

The block diagram:

The schematic:

Video of my submission below: