Eky
Newbie level 2
Hay
Im doing a school project with QT401 slider and im having problems understanding how it works,i have manual which i copy from their main site buth its just a basic operations described .
Im interested in proces of sensing touch position on strip ,like there are two electrodes connected on strip which is made of 18 pads connected in series with resistors .
I know that positions are already defined with algorithms buth im not shure which path is taking for caculation and second i know that output signal (before it goes in ADC) is linear ramp,now the thing is that im short with basics of electronics :
My definition which i goath from manual:
burst impulses travel from electrode 1 through slider and charging CS2 so if i touch slider on "position 6" i will add paralel capacitance to that spot and analog result for added charge is already defined so the only thing to do is measure the voltage on CS2 and the touch spot is fixed with amount of voltage that you will get from it.Process is done in both way for recalibration of end positions
I goath image of burst signal and it has shape of amplitude reducing impulses which
are proabably lead to an integrator so well get an linear output for further A/D conversion now if you let that signal through touched slider what happens ?
-Is signal coupled through finger to ground and well get smaler amplitude
or
-Is charge from touch added to burst signal and well get higher amplitude
----------------------------------------
I know that im complicating buth if anyone knows how it works please help me its giving me a headache and sory for my English,cheers
Im doing a school project with QT401 slider and im having problems understanding how it works,i have manual which i copy from their main site buth its just a basic operations described .
Im interested in proces of sensing touch position on strip ,like there are two electrodes connected on strip which is made of 18 pads connected in series with resistors .
I know that positions are already defined with algorithms buth im not shure which path is taking for caculation and second i know that output signal (before it goes in ADC) is linear ramp,now the thing is that im short with basics of electronics :
My definition which i goath from manual:
burst impulses travel from electrode 1 through slider and charging CS2 so if i touch slider on "position 6" i will add paralel capacitance to that spot and analog result for added charge is already defined so the only thing to do is measure the voltage on CS2 and the touch spot is fixed with amount of voltage that you will get from it.Process is done in both way for recalibration of end positions
I goath image of burst signal and it has shape of amplitude reducing impulses which
are proabably lead to an integrator so well get an linear output for further A/D conversion now if you let that signal through touched slider what happens ?
-Is signal coupled through finger to ground and well get smaler amplitude
or
-Is charge from touch added to burst signal and well get higher amplitude
----------------------------------------
I know that im complicating buth if anyone knows how it works please help me its giving me a headache and sory for my English,cheers
