Capacitive sensor keypad

Forum 2005-2010 (read only) Hardware Interfacing
1

Forgive me if the answer is somewhere on the forum, but believe me I have tried to find it.

I am looking into making a capacitive keypad. Something along the lines of 12 buttons or so. Since this would take up all the digital I/Os on my arduino I was looking for another way of expanding the number of capacitive sensors I can have. I have seen mention of possible using a multiplexer to do this, but no real explanation.

I was wondering if the capSense library would work with something like that or if not how exactly I would go about adding more inputs to be used as capacitive sensors.

Thanks!

2

You can't really use the simple kludge sensors technique for a key pad, it's far too unreliable. You need a chip something like this:-

But there are lots of others.

3

Wow, that was quick, Grumpy_Mike! This is exactly what I am looking for. I don't suppose you could go 3 for 3 in answer these next two questions? Any pointers on how to go about using this with the arduino and how best to get into prototyping without having to solder this type of component?

Thanks so much again for pointing me to the touch sensor!

4

how best to get into prototyping without having to solder this type of component?

The easiest way is to use a development or evaluation kit, they are not too cheap but see this list:-

go about using this with the arduino

Just read the data sheet but most of them use I2C or SPI interfacing so look that up for the arduino.