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:

Capacitance of the body?

February 19, 2011 by · 1 Comment
Filed under: Blog, Uncategorized 

Take a look at this… a 555 circuit that powers on an LED when your place your hand near it.

Lets see if i can get this down to just one 555, with predictable results. Thinking of using it for something…

from NESIT’s 555 build off day, made by one of our junior “members”.

Please Be Discrete

January 20, 2011 by · 1 Comment
Filed under: Projects 

The 555contest has triggered (pun!)  a desire to be discrete. No, im not talking about conservative speech or keeping secrets, im talking individual componants!

It looks like im not alone! Someone has already been looking into this on Dave Jones’s eevblog

The forum user has linked to a schematic which may have been used to digitaly simulate the inner workings of the 555 timer.

I recall using a tool called (Circuit builder?) in high school to design basic digital/analog circuits. I wonder if i still have it installed on an old laptop somewhere…

My goals:
Reverse engineer the inner workings of a 555 timer chip.
Build a functioning 555 timer chip with “socket” extension that can be plugged into various “test boards”.
Make 2-3 test boards (blinky lights, pwm controller, one shot/debounce)
Design and etch clean looking boards for the 555 and test boards

Simulation software (circuit builder, pspice or lt spice)
Circuit board design software (eagle)

Linear Technology LTspice IV …examples\Educational\NE555.asc

Parts list (potential):
Transistors: BC847B (NPN ones) and BC857B (PNP ones)
Q1 N5 5 N7 1 NP
Q2 N1 6 N6 1 NP
Q3 N1 N6 N8 1 NP
Q4 N5 N7 N8 1 NP
Q5 7 N16 1 1 NP
Q6 N17 N14 1 1 NP
Q7 N1 N1 N3 1 PN
Q8 N17 N1 N2 1 PN
Q9 1 N5 N2 1 PN
Q10 N5 N5 N4 1 PN
Q11 N11 N20 N9 1 PN
R1 8 N3 4.7K
R2 8 N2 830
R3 8 N4 4.7K
R4 8 N9 1K
R5 8 5 5K
R6 8 N22 6.8K
Q13 1 2 N10 1 PN
Q14 N14 N10 N11 1 PN
Q15 N13 N12 N11 1 PN
Q16 N13 N15 N12 1 PN
R7 N14 1 100K
R8 N13 1 100K
R9 N15 5 5K
R10 N15 1 5K
R11 N8 1 10K
Q17 N16 4 N18 1 PN
Q18 N19 N17 1 1 NP
R12 N18 N20 5K
Q19 N20 N20 8 1 PN
Q20 N21 N20 8 1 PN
Q21 N21 N19 1 1 NP
R13 N17 N21 4.7K
Q22 8 N22 N23 1 NP
Q23 N22 N21 N24 1 NP
Q24 8 N23 3 1 NP
R14 3 N23 3.9K
Q25 3 N25 1 1 NP
R15 N25 N24 220
R16 1 N24 4.7K
R17 N24 N16 10K
D2 3 N22 D
D1 N18 N19 D
.MODEL NP NPN(BF=125 Cje=.5p Cjc=.5p Rb=500)
.MODEL PN LPNP(BF=25 Cje=.3p Cjc=1.5p Rb=250)
.MODEL D D(Is=1e-12 Cjo=1p Rs=5

to be updated as the project procedes!

555 Challenge

January 19, 2011 by · Leave a Comment
Filed under: Blog 

Twitter is alive with excitement over the 555 Timer. Jeri Ellsworth (twitter) has sparked an interest in this 40 year old IC.  With the help of Chris Gammell and some fellow hackers and engineers , She has proposed a design challenge contest revolving around this simple timer/multivibrator 8 pin dip.

Details are still forming, and are available on Twitter rumors (tumors?) indicate that element14, digikey and designspark are interested in sponsoring this contest.

pick up yours today!
Digikey ( DIP , SMT )
Talonix (High Temp Ceramic!)
Electronicplus (Metal TO-5 package – search for 555can)

Im sorry Dave… Im afraid I can’t do that.

January 18, 2011 by · Leave a Comment
Filed under: Uncategorized 

Thanks to Dave, for the tweaked revolution-code-blue theme.

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