Short Range Reflective
Object Sensor - Drawing only 30uA from a 3v supply, this circuit will detect a human
finger with a range of about 1 inch. The sensor uses an inexpensive infrared LED and a matching photo diode . . .
[Circuit by Dave Johnson P.E., 07/09/06]
Simple Touch Alarm Circuit
- Touch the sensor of the alarm with your finger and it starts beeping, goes on for some time and then stops.
Touching it again, and it goes again! This little and flexible circuit consists of a touch sensor and a directly
coupled transistor amplifier with a small loudspeaker as the output load. Two sensor strips of metal are. . .
[Circuit Posted by T.K. Hareendran]
Single Output 120VAC
200 Watt Touch Switch - This simple circuit uses a single IC to form a nice touch
switch circuit. A single transistor forms the remote active switch sensor. Multiple switches can be wired in
parallel. The switch circuit can be located about 500 feet from the control circuit. . . . [Hobby Circuit
designed by David Johnson P.E., 02/07/10]
Solid
State Touch Activated Switch - It does not get any easier if you want a solid state
switch that is activated by the touch of a finger. Two small metal pins route voltage through the finger skin to
a MOSFET switch. The circuit is great for situations where a membrane type mechanical switch . . . [Hobby Circuit
designed by David Johnson P.E., 06/03/00]
Through Glass Push Button
Switch - This simple technique allows a mechanical pushbutton switch assembly to
activate a reed type relay through a pane of thick glass. Pushing the button moves a magnet near the reed
relay, closing the relay contacts. . . . [Circuit by David A. Johnson P.E., 11/07/10]
Through
Glass Pushbutton Switch - This simple technique allows a mechanical pushbutton switch
assembly to activate a reed type relay through a pane of thick glass. Pushing the button moves a magnet near the
reed relay, closing the relay contacts . . . [Hobby Circuit designed by David A. Johnson P.E., 02/10/02]
Touch Activated Lamp
- The circuits below light a 20 watt lamp when the contacts are touched and the skin resistance is about 2 Megs
or less. The circuit on the left uses a power MOSFET which turns on when the voltage between the source and gate
is around 6 volts. The gate of the MOSFET draws no current so the voltage. . . [Bill Bowden's circuit]
Touch Activated Switch
- This circuit provides about one watt of non-isolated DC power for an automotive type 12v LED array lamp in
addition to a standard incandescent table lamp. . . . [Circuit by Dave Johnson P.E., 01/18/02]
Touch Alarm for Door
Knob - I designed this hobby circuit many years ago and it seems be a very popular
construction project. Many companies offer simple alarm devices for personal use in bedrooms or hotel rooms. A
metal chain attached to a box holding the electronics is place . . . [Hobby Circuit designed by Dave Johnson
P.E., 05/29/00]
Touch Controlled Mute
Switch with 555 IC - Here is another simple circuit to mute the volume of Audio devices
through simple touch. It exploits the action of the flip-flops in the timer IC 555 to reduce the volume of the
Audio amplifier. IC NE555 is designed in the toggle mode. Its lower and upper comparator inputs are connected to
the touch plates which can be. . . [Circuit Posted by D Mohankumar]
Touch 'N Flip
- Ever wonder how a touch plate, like the kind you see on some elevators and lamps work?This circuit will give
you a feel for how the touch plate works in a circuit and you can expand on the circuit to suit your project
needs. The touch plate. . . . [Randy Linscott's design]
Touch sensistive touchpad
- What to give your next project that distintive 'high tech' look? Want to do it for under $5? I make my own
single sided boards for most of my projects lately. This board layout was created using the SOIC version of a
PIC16F627A without drawing the usual schematic first. Most of the part values are etched on the Layout. The SIP
resistor packs I used are 10k ohm, some experimentation with this value may be useful. . . . [by Luhan
Monat-Mesa Arizona]
Touch
Sensor Switch Circuit with 555 timer - This is a very simple touch sensor switch that is
build with the 555 timer IC. You just need to touch the metal plate and the relay gets energised and is kept in
this state for about 100 seconds, then is released. This kind of sensor switch is suitable for making touch
operated bells, buzzers of small toys which operate for a. . . [Circuit posted by Popescu Marian]
Touch Switch
- The Touch Switch circuit will detect stray voltages produced by mains voltages and electrostatic build-up in a
room. In the first circuit, pin 2 must see a LOW for the circuit to activate. If sufficient static voltage is
detected by the plate, the chip will change state. If not, you will need to touch the plate and the 0v rail. . .
[designer's name not found on the website]
Touch Switch - A
touch switch is a switch that is turned on and off by touching a wire contact, instead of flicking a lever like a
regular switch. Touch switches have no mechanical parts to wear out, so they last a lot longer than regular
switches. Touch switches can be used in places where regular switches would not last, such as wet or very dusty
areas. . . [Circuit designed by Aaron Cake]
Touch Switch
- This circuit uses a 555 timer as the bases of the touch switch. You can learn more about 555 timers in the
Learning section on my site. When the plate is touched the 555 timer is triggered and the output on pin 3 goes
high turning on the LED and the buzzer for a certain period of time. . . . [Randy Linscott's design]
Touch Switch 240VAC
- This is another capacitance based touch on/touch off switch, which can control power to a 200 watt 240vac load
. . . [Hobby Circuit designed by Dave Johnson P.E., 02/12/02]
Touch Switch Circuits
- Here is a great collection of touch switch circuits. A touch switch is an electronic device that enables us to
control a circuit by simply touching a sensor. Simple touch switch circuit with 4011 – source The circuit as you
can see from its diagram is very simple and only uses 8 components. The heart of the circuit is. . . [Circuit
posted by Popescu Marian]
Touch Switch
Circuits - All the circuits and projects we describe in these articles consist of very
important "building blocks" that you can add to other designs. This time we describe the concept of touching a
plate (or two plates separated by a small gap) and turning a circuit ON or OFF. A TOUCH PLATE is classified as a
high impedance device. . . [email Colin Mitchell: talking AT tpg.com.au]
Touch Switch
controls a 120 VAC load - This is a capacitance based touch on/touch off switch, which
can control power to a 200 watt 120vac load . . . [Hobby Circuit designed by David A. Johnson P.E., 07/11/06]
Touch Switch Exciter - If you have hundreds of touch
switches that need an excitation signal, then this circuit is what you need. Its 20KHz 20v peak to peak output
signal can supply up to 3 watts of touch switch excitation power . . . [Hobby Circuit designed by David A.
Johnson P.E., 02/11/02]
Touch switch needs no DC return path - 02/03/05 EDN Design
Idea Common designs for touch switches detect a decrease in resistance when a user's fingertip either connects
a contact to the circuit's common ground or supplies an injection of 60-Hz ac voltage, resulting from immersion
in the electro. . . [by Brad Albing, Philips Medical Systems Inc, Cleveland, OH]
Touch triggered alarm -
No description available. . . [Posted by Jospfh]
Touch-Activated Timer Switch Extends Battery Life - 10-Jul-08
EDN Design Idea Designed to fit into the battery compartment of an optical mouse, this circuit automatically
shuts off the battery after a time delay. . . [by Israel Schleicher, Prescott Valley AZ]
Touch-controlled Dimmer - Here’s a dimmer that, besides being
touch-controlled, also has a setting memory that enables it, for example, to turn the lighting on at the level
you had set last time it was turned off. The project uses a specialized IC, an LS7534 from LSI Computer Systems,
available from Farnell, among othersmust register on this site. . . [Published in Elecktor July/Augu, 2010]
Travel Touch Alarm
- The Travel Touch Alarm can be used to provide a audible alarmwhen someone touches the door knob or handle of
your hotel room. The door knob or handle must be made of metal for the circuit to work. The main chip in the
circuit is a 555 timer. . . . [Circuit design by Randy Linscott] |