figure touch pad

Thread Starter

boby4u

Joined Jun 1, 2007
26
I am going to make a finger touch pad .
first of all I wanna get some information about that would you mind giving me some, if you khow any sites?
 

lightingman

Joined Apr 19, 2007
374
Hi...Ther are a few ways of doing this.....One is by using the stray hum pick-up from your finger... You just amplify and rectify this to trigger what ever you need to.....The next method is the capacitive one, whereby you send a square wave signal into one input of a CMOS exclusive or gate (4030/4070), then the same signal through a 4.7Meg resistor to the other input (this input also being the touch plate)..... The idea being that when both inputs are high or low, there will be a logic 0 at the output.... When you touch the plate it will alter the time constant of the signal into the touch plate input, causing the output of the gate to produce pulses....The other method is by using a touch plate made in 2 sections and detecting the resitance change when the finger touches the plate...Hope this helps...Daniel.
 

Thread Starter

boby4u

Joined Jun 1, 2007
26
wowwww
thank you very much .
I don`t think I could find this information elsewhere.
I googled the web befor but found nothing.thanks a lot
 
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