I've been lurking these forums for the last year getting info and ideas for a project I want to understake. The wealth of knowledge is incredible and, as a "thank you", I decided to post up this guide. It's my first so please feel free to offer up any constructive criticism. Part of my project will make use of touch-sensitive buttons. Electrodes will be placed behind a plexiglas panel to activate these buttons. I mostly see questions about power switches, so I'll cater to this, but the QT110 will ground its output on activation (active-low) so you can use it for any button that does this. The QT110 by QProx (datasheet here, PDF) is actually a very simple IC to implement in a circuit. Better yet, it's CHEAP! All it really needs to function is a 10nF capacitor (non-electrolytic per their instructions), an electrode, and a 2.5-5VDC power supply. In this guide, I'll add some other options supported by the QT110 that might be of interest to the PC modder. First, the parts list: 1 x Breadboard (Radio Shack p/n 276-150) 1 x QT110 IC (Digikey p/n 427-1000-ND) 1 x IC socket (Digikey p/n A24802-ND) 1 x Piezo sounder (Digikey p/n P9910-ND) 1 x 475kOhm resistor (Digikey p/n 475KXBK) You'll also need some wire, and (obviously) some soldering equipment. For wire, I use 20-gauge solid-core wire because it fits nicely into the holes in the breadboard. It's a little less flexible than braided-core, but I find it easier to solder and trim. First, we set up the signal path around the breadboard: For the most part, I use lead clippings from resistors to make jumpers. Don't worry, I know it looks sparse, but it'll make sense as we go along.