Thundercat
Well-known member
Hi all, I'm keenly interested in creating a capacitive touch pot. I've settled on the Alpha endless potentiometers, RV112FF-40B1-15F-0B20, https://www.mouser.co.uk/ProductDetail/317-1240FF-15F-0B20K, and I know these have been used for this purpose.
They do not have a dedicated touch wiper and the metal shaft has a bit of connectivity with the body - when I test on my meter it bounces around from 75R to 200R and anything in between (not sure why that's the case). But there does seem to be some conductivity between the pot shaft and the body.
I'd love to be able to have capacitive touch on these pots, but I'm not clear how to proceed. Since the pots don't have high conductivity, I'm not sure they would work with just attaching a wire to the body of the pot through a 1M resistor to a Teensy pin.
Maschine made by Native Instruments (NI) has touch-sensitive pots. You can see a video of it in action here:
What you're seeing is the pot board, and the Alpha pot being used:
And a couple closeups:
I see some kind of interesting PCB pattern on the underside of them, which I assume is related to the capacitive touch, but I'm not sure.
Also there's a setting in the options for low or high touch sensitivity too.
Does anyone have any insights into what this curious PCB pattern on the underside of the pots may be doing, and how they might be achieving capacitive touch with it? And also even without this mysterious PCB do you think cap touch can be implemented with a slightly conductive pot knob to body?
Thanks for your thoughts.
Mike
They do not have a dedicated touch wiper and the metal shaft has a bit of connectivity with the body - when I test on my meter it bounces around from 75R to 200R and anything in between (not sure why that's the case). But there does seem to be some conductivity between the pot shaft and the body.
I'd love to be able to have capacitive touch on these pots, but I'm not clear how to proceed. Since the pots don't have high conductivity, I'm not sure they would work with just attaching a wire to the body of the pot through a 1M resistor to a Teensy pin.
Maschine made by Native Instruments (NI) has touch-sensitive pots. You can see a video of it in action here:
What you're seeing is the pot board, and the Alpha pot being used:
And a couple closeups:
I see some kind of interesting PCB pattern on the underside of them, which I assume is related to the capacitive touch, but I'm not sure.
Also there's a setting in the options for low or high touch sensitivity too.
Does anyone have any insights into what this curious PCB pattern on the underside of the pots may be doing, and how they might be achieving capacitive touch with it? And also even without this mysterious PCB do you think cap touch can be implemented with a slightly conductive pot knob to body?
Thanks for your thoughts.
Mike