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General Category => General Discussion => Topic started by: ia_85 on November 10, 2014, 00:12:44 AM

Title: Capacitive touch question
Post by: ia_85 on November 10, 2014, 00:12:44 AM
Hello,

I sew all the vids and the different methods for building a capacitive touch sensor.

In my project i wish to use a 3 big surfaces as the touch buttons.
the surfaces sizes are 10X10cm , 50X50 cm, 100X100 cm.
the surfaces resistance is 200-300 ohm.

what is the best capacitive method to use - hum ? frequency ? voltage ? any other method ?
could there be a problem with this size of surfaces ? if so , why is that ?

Thanks.
Title: Re: Capacitive touch question
Post by: cheerio on November 11, 2014, 15:06:51 PM
i would use the charge/discharge method. but make sure to protect your mcu from high voltage, because the touch area is like an antenna that can catch elektromagnetic waves and produce high voltages.
just use a resitor + zener diode for protection i guess...
Title: Re: Capacitive touch question
Post by: kam on November 11, 2014, 21:07:08 PM
well, actually the size is rather big. the capacitance with ground will be bigger and more significant than the body capacitance. so i would not use capacitive method. Sensing a touch will be hard, you will always be between touch and proximity. Unless of course if you find a way to reduce the sensor's capacity ... hard  :-\

what is the application?

Title: Re: Capacitive touch question
Post by: cheerio on November 13, 2014, 01:03:07 AM
i would try to use a mesh for the big areas. should be less capacitance