Touch Sensor Switch Using Inverters

This touch sensor switch can is designed using inverters (N1, N2)and some common electronic components. In standby state at the entrances of N1 there is a signal produced by oscillator N3/N4. At the touch sensor hand capacity forms a bridge to the ground for the 1MHz signal so that the voltage signal at the entrance of N1 decreases more (at the exit of N2 is logical 1). After the release of contact, a signal charge C4 through D1 Mhz, so the output of N2 is 0 logic after short time.

Touch Sensor Switch Using Inverters Circuit Diagram

Installation can be powered with a DC voltage between 3 and 15 volts (maximum current of 2 mA is absorbed).

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The Gentle Touch Circuit Diagram

Consumer home equipment in this day and age hardly have a proper mains switch. Instead, appliances are fliped on and off on the contact of a button on the faraway control, similar to any other perform. This circuit displays how a tool (as lengthy because it does not draw too excessive a present) can be swaped on and off the utilization of a pushbutton. The means requires that a microcontroller is already available within the circuit, and a spare input port pin and a spare output port pin are required, along with just a little software program. When power is applied T1 initially is nonetheless fliped off. When the button is pressed the gate of T1 is taken to floor and the p-channel energy MOSFET conducts. The microcontroller circuit is now equipped with energy. Within a short duration the microcontroller must take output PB1 excessive. This activates n-channel MOSFET T1 which in flip preserves T1 turned on after the push-button is launched.

Now the microcontroller must poll the state of the push-button on its enter port (PB0) at regular intervals. Immediately after change-on it will observe that the button is pressed (a low degree on the input port pin), and it must look ahead to the button to be launched. When the button is next pressed the software should swap itself of f: to are attempting this the firmware running in the microcontroller must set the output port pin to a low stage. When the button is subsequently launched T1 will now flip off and the availability voltage will be removed from the circuit.

The circuit itself draws no present within the off state, and for (rechargeable) battery-powered appliances it is therefore absolute best to position the switch ahead of the voltage regulator. For primarys-powered instruments the change can be geared up ahead of the voltage regulator (after the rectifier and smoothing capacitor). Since there's no majors switch there will nonetheless be a small standby current draw on this case because of the transformer. Be careful not to exceed the maximum gate-source voltage specification for T1: the IRFD9024 software prompt can face up to up to 20 V. At decrease voltages R2 could be changed by way of a wire link; otherwise appropriate values for the voltage divider formed by using R1 and R2 must be chosen.

Circuit diagram:

 The Gentle Touch Circuit Diagram

The writer has arrange a small website for this challenge at http://reweb.fh-weingarten.de/elektor, which gives source code examples (which embody dealing with pushbutton contact bounce) for AVR microcontrollers suitable for use with AVR Studio and GNU C. Downloads are additionally on hand at http://www.elektor.com.

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Touch Door Alarm Circuit Using 555 Timer IC

This is a design simple alarm that can be used to provide a audible alarm when someone touches the door knob or handle of your 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 which will be triggered if a hand comes close to or touches the door knob.


The circuit attaches to the door knob at the end of the 1 Mega ohm resistor. This is operation of the circuit. Once the timer is triggered the LED will light and the UJT will output a tone to the speaker. The timers will time out in 5 seconds. The sensitivity of the trigger can be changed by changing the 1 Mega ohm resistor to another value. The 5 second time out can be adjusted by changing the value of the resistor connected between pin 8 and pin 7. The output tone can be changed by changing the RC values on the base of the UJT.

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Touch Switch using NE555

The series of touch switch or touch switch is built by IC NE555, a series of touch switches can be used to turn on lights, alarms or other electronic equipment.
This circuit uses 2 pieces of metal plate media as touch, MP1 (Metal Plate 1) and MP2 (Metal Plate 2). Touch switch circuit is equipped with a visual LED indicator for relay status (load active). To enable (Relay ON) can be done by touching the surface of MP1 and to turn it off by touching the surface of the MP2. MP1 and MP2 in touch this switch can use a small piece of copper (diameter 5mm) was enough.

Touch Switch series with NE555.

Component List 555 touch Switch
R1 = 3.3M
R2 = 3.3M
R3 = 10K
R4 = 1K
C1 = 10nF-63V
D1 = 1N4007
D2 = Red LED
Q1 = BC547
IC1 = NE555
RL1 = 12V Relay

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