Apparently, the actual Sonic Screwdriver TV prop has a button on the leather grip area that the actor presses to activate the Sonic, but it's cleverly never shown in the TV show. The Wand Company believes that it was not intended for the overall look of the Sonic, and I agree with them. So instead of placing a button on the leather grip area, like I've seen in most Sonic Screwdriver modifications on the internet, I was thinking about adding a Force-Sensing Linear Potentiometer Strip (FSLP) under the leather-like grip area. Maybe not that exact one I posted in the link above, but something similar that is a bit wider. I'll also have to consider the operating temperature and power usage; it gets really cold where I live. According to one company's website: FSLPs are rugged, moisture resistant, low power consuming, and can be used with fingers, stylus, or gloves even in harsh conditions. So bonus marks there if that is all true.

Might set up the sensor to adjust the frequency of the Sonic sound to something like the more force you apply the higher the frequency of the Sonic Screwdriver sound. Not sure if this is plausible tho, because I'm not really certain if you can remove the leather-like grip layer without damaging it.

Anyway, it's just an idea that popped in my head, if it turns out to not be feasible then I can probably live with just using the gesture controls.