Using Frequency division Multiplexing for capacitive sensors

Thread Starter


Joined Sep 26, 2023
Hi, I am studying the possibility of using the FDM technique for an array of capacitive sensors. I have multiple capacitive sensors and each of them has a wire for stimulating it with a sinusoidal signal and reading the output. Being a lot of sensors and therefore tracks, I need to reduce the number of tracks. I am thinking to use a FDM technique in other to stimulate each of them with a sinusoidal signal at different frequency and then read the output through a single channel with demodulation. could it be done?


Joined Jan 27, 2019
Welcome to AAC.

In principle there's no reason something like what you describe couldn't work. But demodulate wouldn't be the right term for what is sounds like you are proposing.

Could you flesh out the idea so it is possible to tell exactly what you hope to do?


Joined Jan 23, 2018
What might be applicable is diode switching, where the signal from each sensor would pass thru a forward biased diode, while the other sensors would be isolated by unbiased diodes. That would allow one common signal line but still require a separate excitation line for each sensor.
Are there any constraints, such as size, cost, complexity, or power requirements? And what sort of distance is involved? Is this application a capacitive keypad, possibly??