Touch switch - Electronic Circuits Projects Diagrams Free

Asjad · 25th August 2004, 01:59 PM

Does anyone have a link or a circuit for the the following requirement

------------------------------

Easy to understand touch switch circuit.

I would prefer the switch to start a clock so that I can count how long the
switch has been pressed for.

Which is easier to implment:

50Hz detection
Capacitance based
-----------------
THANK YOU FOR YOUR HELP!!!!!!!

grrr_arrghh · 25th August 2004, 02:59 PM

look up CD4026 on the net. The data sheet should probably give you enough info.

If the clock needs to be accurate, you will need a crystal, (or if accuracy is not an issue, a 555 timer IC would do) to give the pulses, which will feed into a 4026, which would cascade into another 4026. Each 4026 will drive a 7-segment display. You would connect your push switch to the 'enable' pin on the first 4026. I have a digram of this lying around somewhere, I'll try and dig it out for you.

The above is probably the simplest way to do it, however, it will only count in seconds. If you want minutes as well, it gets a bit more complicated. However, it would be accomplished using (instead of each 4026) a 4510 and a 4511. The 4510 has a binary output, to drive the 4511 (which drives the 7-segment display). Logic gates can be connected to the binary output and reset the whole thing when it gets to 59 seconds (using the first method it would count up to 99 seconds).

Is this any help?

Tim

grrr_arrghh · 25th August 2004, 03:06 PM

along the lines of my second idea, here are two (the second probably more complex than the first) circuits for you to look at.

http://users.otenet.gr/~athsam/samgordon_clock_eng.htm
http://users.otenet.gr/~athsam/samclock_english.htm

Asjad · 25th August 2004, 03:12 PM

I think you misunderstood me, I need a simple circuit for a

touch sensetive circuit

McGuinn · 25th August 2004, 03:22 PM

Quote:

Originally Posted by Asjad

I think you misunderstood me, I need a simple circuit for a

touch sensetive circuit

Correct, but no misunderstanding.
The CD4026 will allow you to measure the time that the button has been pressed. All you really need to do is get busy with your school project and search google/books on the topic of touch switches.

grrr_arrghh · 25th August 2004, 03:27 PM

lol, McGuinn, my electronics teachers were very fond of the 4026...partly why I suggested it.

as suggested, google 'touch switch'. It comes up with exactly what you're looking for.

Tim

kentken · 26th August 2004, 01:38 AM

Look up qt60040
http://www.qprox.com/products/qmatrix.php

Kent

niq_ro · 26th August 2004, 07:25 AM

look at http://www.niq.dap.ro/senzor.htm
are there a few senzor

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25th August 2004, 01:59 PM	(permalink)
Asjad	Touch switch Does anyone have a link or a circuit for the the following requirement ------------------------------ Easy to understand touch switch circuit. I would prefer the switch to start a clock so that I can count how long the switch has been pressed for. Which is easier to implment: 50Hz detection Capacitance based ----------------- THANK YOU FOR YOUR HELP!!!!!!! __________________ Best Regards

25th August 2004, 02:59 PM	(permalink)
grrr_arrghh	look up CD4026 on the net. The data sheet should probably give you enough info. If the clock needs to be accurate, you will need a crystal, (or if accuracy is not an issue, a 555 timer IC would do) to give the pulses, which will feed into a 4026, which would cascade into another 4026. Each 4026 will drive a 7-segment display. You would connect your push switch to the 'enable' pin on the first 4026. I have a digram of this lying around somewhere, I'll try and dig it out for you. The above is probably the simplest way to do it, however, it will only count in seconds. If you want minutes as well, it gets a bit more complicated. However, it would be accomplished using (instead of each 4026) a 4510 and a 4511. The 4510 has a binary output, to drive the 4511 (which drives the 7-segment display). Logic gates can be connected to the binary output and reset the whole thing when it gets to 59 seconds (using the first method it would count up to 99 seconds). Is this any help? Tim

25th August 2004, 03:06 PM	(permalink)
grrr_arrghh	along the lines of my second idea, here are two (the second probably more complex than the first) circuits for you to look at. http://users.otenet.gr/~athsam/samgordon_clock_eng.htm http://users.otenet.gr/~athsam/samclock_english.htm

25th August 2004, 03:12 PM	(permalink)
Asjad	I think you misunderstood me, I need a simple circuit for a touch sensetive circuit __________________ Best Regards

25th August 2004, 03:27 PM	(permalink)
grrr_arrghh	lol, McGuinn, my electronics teachers were very fond of the 4026...partly why I suggested it. as suggested, google 'touch switch'. It comes up with exactly what you're looking for. Tim

26th August 2004, 01:38 AM	(permalink)
kentken	Look up qt60040 http://www.qprox.com/products/qmatrix.php Kent

26th August 2004, 07:25 AM	(permalink)
niq_ro	look at http://www.niq.dap.ro/senzor.htm are there a few senzor __________________ see http://www.tehnic.go.ro & http://www.niq.go.ro