Overcoming design challenges: the touch button for the Pendrive S3

How can you add a button to a device without drilling a hole in its enclosure? This was the challenge Dani Eichhorn faced when designing the Pendrive S3, as Dani wanted to use an off-the-shelf USB enclosure. Drilling a hole was an option, but the aim was for the Pendrive S3 to resemble a regular USB stick without any conspicuous buttons altering its exterior.

The solution became clear: a capacitive touch button. These buttons are ubiquitous in modern devices, from stoves to elevators. The primary advantage of a touch button is that it doesn’t require openings in the surface, preventing water or dirt from entering the electronics.

Searching the JLCPCB catalog for “spring” yielded many options. Under “press spring,” are suitable components, including variations with one pin soldered in the center and others with two pins, all through-hole. Knowing the distance between the PCB and the enclosure was 4.6mm, one needed to determine how much force was required to compress the spring to fit into the enclosure. Experimentation provided the answer.

See the video below and more in the post here.


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