I happened to use an Atmel Qtouch chip in a project recently. The particular part was AT42QT1040, used in a fairly typical application- replacing four tactile buttons with four touch buttons. The chip is literally a “black box” that you give power, connect a few passives to the electrodes and in return you get four digital outputs representing the status of each key. No software to write, and is very simple. This particular feature came up very handy when a customer recently decided to switch from tactile to touch buttons mid-design. Since I was using Altium Designer on this project, the electrodes were essentially a freebie for me. I simply used Atmel Qtouch library, added the rectangular buttons into my schematic as components and Continue reading →