***"Touch Control" Switch Circuit***

Submitted By "JoeTestingEngr"

Here is a "Touch Switch" Schematic, submitted by "JoeTestingEngr".

This device may be used to turn on and off a Load, simply by touching the probes (plates) with a finger.

Typically, these controls perform as "Touch Once for On, Touch Once Again For Off" when controlling a simple "On/Off" function for a Load, such as an Incandescent Lamp; but they may also perform as "Touch And Hold To Dim (up or down), Touch Again For Off" control of an Incandescent Lamp load.

This Schematic may be discussed at the Electrical Theory and Applications area, under the topic of:

Touch Switch Discussion

Click the hyperlink above to open that thread in a new window.

Member's Text Below:


Here is a tif of a circuit that might be of interest to some.
I would probably call it, "Touch Pads, Current Sensing, and Time Delays."

On background, this circuit is part of my little one's fountain.

A 4017 Johnson decade counter drives a transistor array through a diode matrix.

The array sinks current to strings of red, yellow, and super bright red, yellow, white, and blue LEDs, shining up through the water.

The 0 output of the counter doesn't drive any LEDs so I can hold the counter reset if I wish to drive the LEDs by other means.

As she grew a little older, I wanted her to see a little cause and effect.

Here, she can touch brass rods embedded in a pine rosette to directly drive the colors.

The current is sensed and used to drive the reset pin of the 4017 high.

The sequence is allowed to resume about 10 seconds after she gets bored and stops touching the pads.

The next project is to drive the LEDs from low-pass, 2 band-pass, and high-pass filter circuits, to kid's music, like the old color organs.

The tail end of this circuit could have just as easily driven BigB's automotive relay, instead of pulling down a 15K resistor.

The BS-108 can switch 300mA at 200V. The middle shows a good way of sensing current to switch things.



Moderator's Note:

Thanks to Joe for the Contributions!!!


posted 07.15.2006 @ 01:41:00
local = x:\elect_eng02\ECNusers\upload\Touchckt.jpg
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!