For those of you that are looking for cheap, alternative capacitive sensing solutions, here is the CapSense chip from Cypress that I’ve been using for my recent music controller projects. Below you can find the test code Nan Zhao and I put together for CY8C20 a four-input interface. It’s relatively straightforward to use compare with other capacitive sensing solutions and it also supports PWM outputs if what you need is simple. . Like every other capacitive sensing chip, it has a strict design rule. But our star shaped buttons seemed to work pretty well. A few important document you might need from time to time..
some Arduino code I wrote for testing - cy8c20 sample code.