Developing a Touch Led

OBJECTIVE:

A touch sensor is a type of equipment that captures and records physical touch or embrace on a device and/or object. It enables a device or object to detect touch, typically by a human user detector or operator. A touch sensor may also be called a touch.

The purpose of this project is to trigger/switch an LED with a simple touch.

COMPONENTS:

• 2 Transistors ( BC 547)
• 2 Resisters (270 ohm,100k ohm)
• LED
• Connecting Wires
• Battery 6V

CIRCUIT DIAGRAM:

Working:

The skins resistance is about 600K-1M. So if you try building a circuit with just an LED, power supply and touch conductors, the LED doesn’t glow. This is because, high skin’s resistance prevents enough current to flow through the circuit. So the only option we have is to amplify the tiny current flowing through the skin to a magnitude enough for an LED to glow. For that purpose, we have to use transistors. The circuit will also work with just one transistor, but the LED doesn’t glow bright enough. So we have used two.

Tiny electric current flows through the skin when the end touch conductors are touched. This tiny current is amplified in magnitude by the first and second transistors and it finally passes through the LED. Refer to the circuit diagram for better understanding.