Touch sensors and conductive paint?

[AndyGadget]

I'm just about to have my first play with the 18M2 and it's touch sensors to get a feel for it in advance of a project I've got in mind.

Rather than using actual metal plates for the sensors, I was wondering if anyone has tried painting detector pads onto the back of a thin piece of plastic sheet with conductive paint. Connection could be done with small pins glued to the opposite side in an out-of-sight area and coated in the paint. Should be OK as long as the film isn't able to flex at that point.

Also, is it OK to use ribbon cable to connect to an array of sensors, or will the capacitance between cores cause interaction and false readings? If yes, would using alternate grounds in the ribbon cable stop this or would the capacitance to ground swamp the inputs?

Time to go and try it, methinks.

 

[Grogster]

I don't see any reason why conductive paint would not work.

As I have learned from others here on the forums: "Why not try it and see?"

You'll soon find out if the PICAXE likes your idea or not...

 

[BeanieBots]

As Grogster states, TRY IT.

Conductive paint should be fine.
As for the ribbon cable, depends a lot on how long it is. (and the piece of string).
You need to calibrate the touch sensor inputs anyway, so you will to a large extent be able to calibrate out any cable capacitance.
Using alternate signal 0v signal is a good way to do it. There will ceratinly be extra capacitance doing that way but it will be a fixed amount and should be possible to compensate for. What it will offer is less cross-talk between channels which is something you cannot compensate for.

 

[1968neil]

I had a problem at work today with a similar problem.

I had to mount a remote radio head in a vehicle which used a CAT5 style lead, the lead was the flat ""ribbon" style.

I had all sorts of problems, so i decided tol use CAT 5 cable (twisted pair).
This completely cured the problems and the test cable was over 60 metres long ! (shortest cable i had on board)
So maybe cat5 or twisted pairs would solve your quandry ?

be intersted to know how you get on.
Regards

Neil