mTouch capacitive sensing

[mackrackit]

Hello mackrackit

I must design the "virtuall buttons" on the glass and the pcb is mounted behind, that is the problem than with normal capacitor sensor with the PIC
or Quantum IC's when a blind people scan with finger the area to find the desired buttons, validate all them, i need the same sensor technique but
validate only when make pressing on the glass.
Hope that with this explanation you can undestand what i mean
Sorry for my bad english

Regards
Pedro

I follow you now. Was not thinking about scanning the buttons.
What about pressure sensitive membrane buttons? Use a piece of acetate with dimples punched from the back.

Your English is fine. My brain is slow

[aratti]

Pedro, your glass pannel could be mounted with retro springs (one at each corner). Place a microswitch in between that validate the choise. The microswitch could be activated only with a finger pressure that you can control using springs that will require the correct compromise between security and usability.

Another way could be to have a separate switch that should be pressed after that the disabled has found the requested command. A vocal staff could be activated after the selection has been made to tell which command has been chosen and to request the pressing of the abilitation command.

Al.

[Pedro Santos]

Hello Aratti

Can´t use it with springs, the glasspanel must mounted fixed with no movement.
It must exist another possibility, but no idea?

Regards
Pedro

[aratti]

if you don't want movement than you can use a Force Sensors, which will measure the pressure againt the pannel, and will anable the command only if the push reach your calibration.

Al.

[sougata]

Hi,

For the blinds http://en.wikipedia.org/wiki/Laser_engraving laser engraved switch marks can be really useful. Rather than actuating a key press you may give a feedback through some digitized sound (Beep, ISD, RomanBlack, VS101, whatever) while the user scans the buttons. Hold (2secs... or whatever), or tap+hold, double tap, mixture of anything goes for registering keypress.

[bcd]

Thinking about your application for blind people.

Would a scan of the buttons to find the active areas not normally be quite fast running of the hands across the device?

Maybe be having software that rejects presses if the previous two buttons next to the current one were also pressed within a fast time-out would allow you to have the scan ability but then also sense the actual button presses.

Might need to make the scan work from either direction as some may scan left to right and some right to left.

bill