How to create a capacitive sensing using MCU ?

[ColdFire]

ipod capacitive sensing

Dear All,

I am using a MCU to create a capacitive sensing switch but have no idea how to do it. Can someone advice how to do it and its principle. Thank you.

Regards

 

[IanP]

Re: Capacitive Sensing

Take a look at this simple example .. see picture below .. more details at:
https://www.redcircuits.com/Page22.htm

Maybe you can implement this idea in your application ..

Regards,
IanP

 

[BeeBop]

Re: Capacitive Sensing

Hi,
I've seen this done with frequency using a 555 timer, but can't find that info now!! However, I do know that there is a sensor: the QT300, which converts capacitance to digital output directly, at 16 bits. You can connect to this device with SPI or UART.
I got mine at http://www.sample.co.kr but am sure this is widely available. Google will give you a data sheet on this 8 pin device.
Hope this is of use to you! Any questions, just ask.
Regards,
Robert

Added after 10 minutes:

Also, you may find Quantum's site at http://www.qprox.com/
They have a whole range of capacitive sensors.
Regards

 

[trader]

Capacitive Sensing

Look at the Cypress PSOC series, they have the capacitive sensing switch build in one of their microcontroller. Apple IPOD is using it