Capacitive touch buttons


I have been working on various applications of capacitive sensing since 1998. Most design activity in the late 1990s focused on capacitive touch buttons. Cypress developed robust methods for sensing very small changes in capacitance (femto farads), which we used to sense the presence or absence of a finger. The “killer application” for this technology was mechanical button replacement. We shipped literally 100s of millions of units into products such as the click wheel iPod, televisions, monitors and all manner of consumer electronics. I helped design capacitive buttons on laptops for large PC OEMs.