Nails as momentary buttons to control IC Switches

Projects General Guidance
1

Hello everyone...

I'm very new to microcontrollers, so please forgive this question if it seems obvious.

I'm looking to build a box that has about 5 or 6 buttons that will control some analog IC switches or 5V relays. I want this thing to be very small, so I was wondering if it was possible to use some capacitive touch buttons to control the Arduino to alter the pins between HIGH and LOW for the IC's to switch their states.

Could I use a screw or nail heads as a capacitive button? Would mounting 5 or 6 of these in a small plastic enclosure work?

Thanks!

2

Years ago I used glass fuses as capacitive touch buttons, with just the top of the chrome caps visible they looked good. IIRC I needed some CMOS logic to detect the touch (pre uC days for me).

So yes it should be OK, as to the detection I would have to think about that but there would be a way, for example the old apply 5v and measure the time it takes to rise.

Rob

3

I'm using this as the basis for my design:
http://www.arduino.cc/playground/Code/CapacitiveSensor

My question is, could I wrap that wire around the nail or screw shaft, solder them together, and then add 4 or 5 more to the box?

I'd like to be able to press more than one at a time, which this design says to leave the pins low if you want to touch more than one at a time.

Would I need anything else besides just the Arduino board? How many inputs would I be able to use with just the Arduino board?

4

I think that would work unless the total capacitance of the final setup was too high.

Do you have an Arduino and a nail? Give it a go.

Rob