Inductive Sensing Design Challenge: USB Microphone based on the LDC1000 Inductance to Digital Converter (week 1)

RE: Inductive Sensing Design Challenge: USB Microphone based on the LDC1000 Inductance to Digital Converter (week 1)

vsluiter — Wed, 07 May 2014 08:01:39 GMT

Very interesting project. Good idea, I'm curious what it will sound like, and whether you'll be able to callibrate for the non-linearity. On the other hand, the amount of displacement will be so small that I wonder whether you'll notice the nonlinearity over that small excitation.

RE: Inductive Sensing Design Challenge: USB Microphone based on the LDC1000 Inductance to Digital Converter (week 1)

Former Member — Wed, 07 May 2014 07:30:12 GMT

I like this project. I think it should be possible to mount a piece of metal with something like silicone glue on a background. It should allow it to vibrate enough to be picked up by the LDC1000.

RE: Inductive Sensing Design Challenge: USB Microphone based on the LDC1000 Inductance to Digital Converter (week 1)

shabaz — Mon, 28 Apr 2014 03:52:01 GMT

Interesting idea! It's quite novel, it will be a single-chip direct-to-digital microphone :-)

Maybe this is how those bone conduction mics work? no idea. It could be an interesting use-case.

RE: Inductive Sensing Design Challenge: USB Microphone based on the LDC1000 Inductance to Digital Converter (week 1)

dougw — Sun, 27 Apr 2014 23:29:29 GMT

Interesting project Sammy,

One issue you are probably pondering, but the readership may not be aware of, is that the moving element and its mount with have natural frequencies where they will vibrate or oscillate when excited. The best way to prevent these vibrations from distorting the audio signal is to ensure all natural frequencies are above the hearing range. This usually means very stiff and very small moving elements, however a mounting structure that allows the element to move also allows it to vibrate. Maybe if the natural frequency of the mount is below the hearing range it would help. For example if you hang a metal disk from 2 threads such that the pendulum frequency is below 20 Hz, then the disk is free to move without "hearing" the swing of the pendulum. Any vertical frequency modes associated with stretching the thread wouldn't register on the sensor because of the direction, also the sound waves wouldn't be providing much vertical excitation. Anyway I am sure it will be fun overcoming the various challenges in this project.

Doug

RE: Inductive Sensing Design Challenge: USB Microphone based on the LDC1000 Inductance to Digital Converter (week 1)

DAB — Sat, 26 Apr 2014 18:46:49 GMT

Hi Sammy,

Good idea. I thought of something similar using a mounted sheet of plastic with a thin metal plate or magnet.

If you draw the plastic tight like a drum head, then you can pickup the vibrations using the LDC detector.

It will be very interesting to see how sensitive your microphone can be given the micron detection capability of the device.

DAB