need help here... what switching device will i use

[kerpogi]

hi, im a student planning on my design.

i don't know what switching device will i use.

i plan to design a device with a switch covered with glass.

what type of switch can i use that will trigger once a touch the glass?

help me please... ASAP

[Ate Shey]

capacitive proximity sensor or retro reflective switch like CNY70 ..

[kerpogi]

thank you, now i have an idea.... ill check it,

[kerpogi]

found it..,

sir... can i use those switches on a small space like 8" x 20" with 70+ similar switches?

and wont it affect its adjacent switch when i trigger on one switch?

[Ate Shey]

found it..,

sir... can i use those switches on a small space like 8" x 20" with 70+ similar switches?

and wont it affect its adjacent switch when i trigger on one switch?

can you give more information about your project, set-up, objectives or layout? .. masyado kasing limited ang info mo so i cannot really say..

[kerpogi]

heheh... sorry,

its a glass keyboard...? the space is limited.., is it possible with those switches?

[zer0w1ng]

A few new PIC MCUs have capacitive sensing hardware built-in.
http://ww1.microchip.com/downloads/en/AppNotes/01101a.pdf

Capacitive sensing is just measuring the changes in the frequency when a capacitive pads is touched.
The monostable oscillator frequency will decrease depending on the amount of touch/capacitance is added to the pad.

Hardware only solution for capacitive sense may fail for the surface can dirtied with ketchup or water thus the capacitance is always added.  Temperature and humidity could also affect the initial capacitance.  The circuit also is susceptible to EMI for grounds on the board layout is decreased to minimize the total capacitance on the pad and lines from the sensors.
But with smart software, the "rest"/no-touch state is computed if the capacitance value stays for a long time using long-term averaging.

Cypress PSoC do also capacitive sensing. In fact they are used in ipods.
http://www.cypress.com/?id=1156&

[kerpogi]

thank you, ill be working on those,
its a big help...,

thank you very much...