Pulse Necklace 02Oct2009

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Hack Notes for pulse choker, Oct 2nd, 2009

Just Eric This Time

After Chung-Hay came in and hacked yesterday on her own, I came in today to work on my own, in order to make a "demo" out of the choker for the open house.

When Chung-Hay left, only 2/5 of the LEDs were working, so that was my highest priority in terms of fixing things.

First, I bought up some acetone, so that I could reconstitute the silver paint. I then painted over the solder points of the LEDs that were not working, trying to make them go. This did fix one LED immediately.

Then I spent a bunch of time on the middle red LED, trying to get it to go. I thought I determined that the LED itself was bad, so I replaced it. But that didn't help. Then I discovered that the power trace and the gnd trace were shorted together, even with no LED on them at all. I proceeded to clean up all the little paint "splashes", and to cut and trim all the conductive thread that might be connecting them. Eventually I found the one thread that was causing the problem, and snipped it. Then I soldered the LED back on and it worked, now I had 4/5, including the three red ones. I stopped there because I was happy enough.

I then found a 9V battery and taped it to the rig, and soldered it into the power wires of the RBBB. Then I used some masking tape to mount the electronics to my chest, some Red Dot cyborg nipples, and I put the armature on my neck.

But, it just flickered like crazy, despite the fast that it had been working mere seconds earlier. Chung-Hay had complained that it was doing this for her too. Then I remembered something that we discovered like a month ago when David was wearing it - if the painted traces touch skin, that messes up the ECG measurement. So I just cut a piece of fabric to go under the main armature and prevent the traces from touching my skin. Presto, the thing worked again.


Party Time

Result: working pulse choker, around my neck, with 4/5 lights blinking in time with my heart! I got lots of compliments about it during the open house. After about 2 hours though someone told me that only 1 light was blinking. I took it off and I think basically the silver paint/solder connections are broken again. I left it on the table for the rest of the night, with the one light blinking like crazy. It still inspired many conversations, and I demoed it many more times by just hooking up my cyborg nipples and leaving the armature on the desk.


Bias Tape Solution

I talked with a lady who had done quite a lot of work with conductive thread, and she gave me a tip that really worked well for her: she protects and guides the conductive thread using "bias tape", an iron on patch kind of fabric thing that is commonly used to hem clothing. She uses it in two different ways: (1) apparently it has two sticky strips, with an area in between them, so you can use it as a kind of "conduit" for conductive thread, you can pull more though, etc and (2) if you place stranded wire on top of the conductive thread, you can use the bias tape to form the mechanical/electrical connection (instead of using solder with crimp beads or similar horrible "solutions"). I am excited to try this solution - it might work as well for the paint as it does for the conductive thread, but either way it's a possible solution to our current connection woes.

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