GoForSmoke:
I have to wonder now where that thread is.
This is the thread Cap sense advice please! - General Electronics - Arduino Forum
I think you will see that he has moved the goal posts a lot since my original comments. My thoughts were:-
- He wanted a capacitive slider sensor that was a meter long. The commercial cap sensor chips do not go that long, I provided a link to one to show him.
- The cap sensor he wanted would have to have transparent conductive coatings applied to the inside of a bent tube. A bit "ship in a bottle" given that conductive coatings are normally put on with vacuum deposition.
- Even bending a 1 meter tube is not something that is practical for a non commercial outfit.
As you see Tony came up with a capacitivly coupled potential divider which gave the promise that it might offer a partial solution but it failed on the transparency requirement and required almost floating pins. That is it was not very reliable. In the meantime GreyArea came up with a sequence of capacitave sensor "notches" that would sometimes work if the hand was dragged from one end to the other.
None of those developments, interesting though they might be, in my mind invalidated my original low key comment that I didn't think his project was possible even if GreyArea thought it did, as mentioned in his linked video.
Most of the time an "impossible" project is made possible by changing the requirements, or making it so unreliable or poor as to be not remotely the same project. I am reminded of the person here who wanted to stream live video using an Arduino. I said it was impossible, and someone jumped in and said it was and "proved it" by showing a project where a 4 by 4 pixel image was streamed off an SD card.
I rest my case. 