Problem with self-built sensor

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Anonymous
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Hello everyone,

   

 

   

i am using the CapSense controller of PSoC.

   

The touching element i built can be seen in the attached file....I coated a transparent conductive layer on the substrate and then separate the layer into eight stripe elements. In the end i made a nonconductive overlayer on top of conductiving eight elements.

   

I programmed the PSoC, assigned the pins, then connected the pins with 8 elements using alligator clamps. When i touch certain element, the corresponding LED light should be on and the LCD also shows the touching position. But it does not work as i wanted, the Capsense controller seems not able to detect the capacitance change from the finger.

   

I  measured the resistance of each strip element (130-200 Ohm), is it because of the high resistive load that the capacitance change cant be sensed?

   

But when i remove the alligator clamps from the touching element and i touch certain clamp, the desired effects were shown.

   

Anyone has idea why cant the finger touch be sensored on the touching elements?

   

 

   

Regards

   

Sammi

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4 Replies
Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked

There is an AppNote showing the design of capsense buttons: www.cypress.com/

   

 

   

Bob

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ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

You may have significant fringing C and general coupling C. Use the tuner

   

to set up the Capsense sensitivities.......

   

 

   

    

   

         

   

http://www.cypress.com/?app=forum&id=2232&rID=53237     Miniprog3 as I2C Bridge

   

 http://www.cypress.com/?rid=105688     CE95287 - CapSense CSD using Tuner with PSoC 3/5LP

   

    

   

          

   

http://www.cypress.com/?rID=58549     PSoC® 3 and PSoC® 5LP CapSense® Design Guide

   

 

   

 

   

 

   

Regards, Dana.

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Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked

Just found one more: www.cypress.com/  This explains a bit more...

   

 

   

Bob

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ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

Some more -

   

 

   

    

   

          

   

http://www.cypress.com/?rID=78578     PSOC 4 Capsense Design Guide

   

http://www.cypress.com/?rID=58549     PSoC® 3 and PSoC® 5LP CapSense® Design Guide

   

 

   

 

   

Regards, Dana.

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