Author Topic: Conductive paint or ink safe enough to activate by lips or tongue?  (Read 8485 times)

J

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Hi, does anyone know of a conductive ink or paint which is durable and essentially food safe? What I'd like to try to do is have a few switches drawn on the clear Lexan tube of a Quadjoy, a mouth-operated mouse used by quadriplegics, similar to the way people have drawn switches on paper and other surfaces using pencils, ink, and paint.

I'm a quadriplegic, and the idea is that I would be able to use the Quadjoy normally, wherein I only touch the last centimeter or so of the tube, and when I want to hit one of the switches, I would just reach a little further down with my upper lip for switches drawn on the top, or my tongue or lower lip for switches drawn on the bottom. Wires would attach near the base to complete the circuits with the MaKey MaKey

Anyone know of something which could be used on the Lexan and wouldn't be dangerous? Of secondary importance would be something which could be used to draw relatively thin lines while maintaining conductivity, and wouldn't wear away quickly.

eric

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Re: Conductive paint or ink safe enough to activate by lips or tongue?
« Reply #1 on: June 25, 2013, 02:38:49 PM »
This is a great question and I hope we can help you out!

I have used conductive paint from Bare Conductive with MaKey MaKey, and that works great, but I wasn't sure it would be able to do what you are interested in. I asked Matt Johnson from Bare Conductive, and he explained that the paint is water soluble, so it would dissolve if your tongue touches, and also the paint is not rated for this type of use. So, that won't work. He also said he didn't know of any conductive paints or inks which would be safe for this because they tend to contain nasty solvents.

I also thought maybe you could use thin strips of adhesive copper tape on the quadjoy, and touch those with your tongue (like this stuff: http://www.adafruit.com/products/1128 ). the problem is that the copper tape has sharp edges so it might not be safe enough to use with your lips or tongue.

Another idea is to attach some metal objects to the quadjoy. Something like a straightened segment of a paperclip. you could attach it to the quadjoy with glue or tape, and then clip on to the other end to connect to makey makey.

I think this last idea is worth a try. Good luck, and let us know how it turns out. I think there are other people out there who could benefit from these ideas, so thanks for posting here!

J

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Re: Conductive paint or ink safe enough to activate by lips or tongue?
« Reply #2 on: July 02, 2013, 11:47:00 PM »
Hey Eric, thanks for looking into this, and for asking Matt. When I couldn't find something I had confidence was safe to use as a paint or ink, I decided to go with something which happens to be very close to your last suggestion. I got some thin copper wire (26 gauge) which will be threaded through some paper at different points. The paper will be wrapped around the Quadjoy and taped in place, acting as a circuit board and diagram for where the wire should be threaded while keeping it in place. Where the wire exits near the base of the tube, it will be spliced to some shielded highly flexible braided cable of a slightly larger gauge, which will be anchored to the main body of the Quadjoy, and connected to the alligator clips which connect to the MaKey MaKey.

I think I will be able to get two switches on top and two on the bottom of the tube if all goes well. Weight is a concern, it could influence the movement and resting position of the tube, but I'm hoping just a little paper and the thin wire shouldn't influence it much.

It'll be a week or two before I can have someone try to put it together for me. I'll report back if we're successful or not.

djl57

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Re: Conductive paint or ink safe enough to activate by lips or tongue?
« Reply #3 on: August 05, 2013, 09:19:18 PM »
J,

I like your idea. Have you tried conductive thread? It's cheap, soft, and flexible. Keep us posted on how it works. Here's a link for some on Amazon:

http://www.amazon.com/Conductive-thread-screen-gloves-texting/dp/B0063UL9DS/ref=sr_1_1?ie=UTF8&qid=1375751412&sr=8-1&keywords=conductive+thread

J

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Re: Conductive paint or ink safe enough to activate by lips or tongue?
« Reply #4 on: August 09, 2013, 07:47:03 PM »
Hi dl57,

I did consider some conductive thread, and even got some stainless steel thread, which has fewer reports of fraying and shedding metallic particles compared to other types, to try along with the copper wire, although I expect the copper wire will work best. Unfortunately, it will be quite a while before I can give it a try, other events and equipment failures have intruded.

eric

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Re: Conductive paint or ink safe enough to activate by lips or tongue?
« Reply #5 on: August 14, 2013, 02:07:13 PM »
Keep up the good work J! I look forward to hearing more updates.

phishphace01

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Re: Conductive paint or ink safe enough to activate by lips or tongue?
« Reply #6 on: August 28, 2013, 02:50:08 PM »
Tinfoil! Works like a charm!
"Everybody is a genius, but if you judge a fish by it's ability to climb a tree, It will live it's whole life believing that it is stupid" - Albert Einstein