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???
02/29/08 19:07
Modified:
  02/29/08 19:10

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#151689 - getting the same problem + my concept
Responding to: ???'s previous message
Since i couldnt make the schmitt trigger output duty cycle similar to the center frequency, i used the 556 timer in astable mode and gave its output to input(pin3) of 567.

I used a scope and checked the duty cycle and time period of 556 output and found that matching with the center frequency(pin5) of 567.
Yet, iam getting only a pulse output at pin8 of 567.

I dont have an Ex-OR gate right now to give the two signals(556 output and 567 center frequency) to it and check the output response. I would possibly do that.

Basically my intention on perfoming the above test is to achieve in getting HIGH/LOW logic state before/during touch of capsense.

So, once i am able to get the required output from the Ex-OR gate (logic LOW before touch and pulses during touch), i have planned to give that to an SR NAND latch with its 'R' input inverted.

This NAND latch acts as a debounce circuit and maintain a constant logic LOW state at 'Q' output during the pulse output from EX-OR gate. Otherwise the 'Q' output will be HIGH.

This is the concept iam trying and would get back if i see success.

Suresh.








List of 18 messages in thread
TopicAuthorDate
Suitable method for implementing capsense            01/01/70 00:00      
   Use a chip !            01/01/70 00:00      
      Other chips            01/01/70 00:00      
         Yes, we explicitely beg your pardon, Erik, Richard            01/01/70 00:00      
   Technical Details on Capacitive sensing            01/01/70 00:00      
   most un reliable - is this a commercial product            01/01/70 00:00      
      for commercial product only..            01/01/70 00:00      
         why its considered unreliable            01/01/70 00:00      
   high/low for before/during touch            01/01/70 00:00      
      What do you mean?            01/01/70 00:00      
         Yes i am going through..            01/01/70 00:00      
            LM567            01/01/70 00:00      
               LM567??            01/01/70 00:00      
                  and..            01/01/70 00:00      
                     Post back your result            01/01/70 00:00      
                        getting the same problem + my concept            01/01/70 00:00      
   Another one - SiLabs            01/01/70 00:00      
   Freescale capactive touch/proximity            01/01/70 00:00      

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