Metal Touch Sensor Switch Module

Metal Touch Sensor Module features a KRS13 darlington NPN transistor, the signal of which is controlled by a circuit part of which integrated type LM393 inside which there are two comparators. When you touch the bare wire bent over the transistor, which is represented by the base of the transistor, the 50 Hz signal around us in a modern home or office is injected into a high gain amplifier. The output of this amplifier is connected to a comparator, the sinusoidal AC signal is then converted to a square wave. Vein sensitivity adjustment by adjusting VR1 trimmer appropriately. If you look closely at the LED you will see a slight flicker, this is due to the output that is represented by a square wave of 50 Hz instead of constant value. 

Features:

• Main chip: LM393
• Working voltage: for DC 5V
• Single-channel signal output
• Low-level output signal used for human body touch sensor alarm
• Adjustable sensitivity
• Pin Connector to board: 4 Pins

Specifications:

Pin Description:

Outputs a signal if the metal pike of the Sensor was touched. You can adjust the sensitivity of the sensor with the controller.

• Digital Out: At the moment of contact detection, a signal will be outputted.
• Analog Out: Direct measuring value of the sensor unit.
• LED1: Shows that the sensor is supplied with voltage
• LED2: Shows that the sensor detects a magnetic field 

Functionality of the sensor:

The sensor has 3 main components on its circuit board. First, the sensor unit at the front of the module which measures the area physically and sends an analog signal to the second unit, the amplifier. The amplifier amplifies the signal, according to the resistant value of the potentiometer, and sends the signal to the analog output of the module.

The third component is a comparator which switches the digital out and the LED if the signal falls under a specific value.

You can control the sensitivity by adjusting the potentiometer.

Note: The signal will be inverted; that means that if you measure a high value, it is shown as a low voltage value at the analog output. 

Package Includes:

• 1 x Metal Touch Sensor Module