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Topic: Extending CapSense Inputs (Read 671 times) previous topic - next topic

asuryan

Jul 09, 2011, 03:37 am Last Edit: Jul 09, 2011, 02:32 pm by asuryan Reason: 1
Hi!

Is there a way to extend the maximum number of capacitive sensors controlled by the
Capsense Library? Because one needs always 2 digital Pins which mades a maximum of
5 Sensors... but nothing else... :( Im thinking of something like the 74hc595 which enables
one to control a nearly infinit number of LEDs!
If it is possible using a certain chip do I have to write my own Capsense Lib when
changing the hardware?

As a base I would like to use the UNO!

Thanks in advance!! :)


tkbyd

You might find useful stuff in....

http://sheepdogguides.com/arduino/art3capsen.htm

In particular, look at the circuit diagram near the bottom... for, say, 4 cap-sense inputs, you only need 5 digital lines. Maybe I mis-understood your post, but if you thihnk you need two lines per input, no, not so.

I hope that's good news?

asuryan

Thanks for your answer!

1. Does that mean that I only need one signal pin and add lets say 8 reciever pins?

2. It would be even more cool, when using only 3 pins and read as many
capacitive sensors as I like! Eg. as I mentiond like the 74hc595 but for inputs. Is there
a chip for extendting inputs and is able to read capacitive sensors?

tkbyd

Quote
1. Does that mean that I only need one signal pin and add lets say 8 reciever pins?...


With 9 pins dedicated, you could monitor 8 touchpads.

Quote
2. It would be even more cool, when using only 3 pins and read as many
capacitive sensors as I like...


Ummm... not sure how to do this!

You COULD probably multiplex the inputs somehow, but then you will have complex polling software to write. Buy a Mega, and have more inputs than you can use!

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