Circuit schematic of Versatile Touch Switch

Introduction

As discussed earlier, the Timer IC 555 based circuit design of this versatile touch switch is a very simple schematic and even a novice can easily understand the circuit diagram for successful assembling of the project. Very few components are used in the circuit design The circuit schematic of the versatile touch switch is given below. 

The circuit schematic

The working of the circuit

The circuit works on a 12V DC power supply, which is fed to pins 4 & 8 of the IC. The circuit triggering bias to keep the output latched is fed to the pin 6&7. 1M ohm resistor along with a 100 MFD electrolytic capacitor determines the timing factor. This RC combination holds for 3 seconds time interval. To start the circuit input signal is given through the touch plate to the input pin 2. Once the touch plate is touched, the circuit is put into action and the output is latched for 3 seconds and then released automatically.  The output pin 3 is connected to a relay through a diode. Whenever the output pin 3 goes high the relay latches and the relay latching is released when the output goes to zero. This is a simple straightforward circuit that works well as a touch switch. Aluminum foil or a small metal piece preferably a copper clad board piece can be used as a touch plate. 

If one wants to do away with the relay, the output can be connected to any other annex circuit for the required performance. Even a simple LED will give an indication of the performance. Hence it is not necessarily a relay that should be connected. Some electronics enthusiasts want to alarm indication either light signal or audio signal, which everyone wants the circuit can be modified as it is flexible for easy adoption. 

Parts list

IC555-1no.

1N4001 Diode- 2 nos.

1M ohm resistor ¼ w-1 no.

100 MFD 25V electrolytic capacitor-1 no.

12V SPST DC relay-1 no.

12V DC power supply / 12 V Battery

General-purpose PCB or Vero board-1 no

Assembling hints

Detailed assembling instructions will be discussed in our next post. As such newbies will not find any difficulties in assembling this circuit.  Please share your comments that help to update the post for the benefit of all.