Circuit Documentation

Summary

This document provides a detailed description of a circuit that includes a gas sensor (MQ-2), a power supply (2x 18650 batteries), a rocker switch, a voltage regulator (7805), a 1-channel relay, and a piezo buzzer. The circuit is designed to detect gas and trigger an alarm using the piezo buzzer when gas is detected.

Component List

1. MQ-2 Gas Sensor

   • Pins: GND, VCC, ANALOG, Digital
   • Description: A gas sensor used to detect the presence of gases such as LPG, i-butane, propane, methane, alcohol, hydrogen, and smoke.
   • Purpose in Circuit: Detects gas and sends a digital signal to the relay.

2. 2x 18650 Batteries

   • Pins: vcc, gnd
   • Description: A pair of 18650 lithium-ion batteries used as the power source for the circuit.
   • Purpose in Circuit: Provides power to the entire circuit.

3. Rocker Switch

   • Pins: 1, 2
   • Description: A switch used to control the power supply to the circuit.
   • Purpose in Circuit: Turns the circuit on and off.

4. 7805 Voltage Regulator

   • Pins: Vin, Gnd, Vout
   • Description: A voltage regulator that converts the battery voltage to a stable 5V output.
   • Purpose in Circuit: Provides a stable 5V power supply to the components.

5. 1 Channel Relay 5V

   • Pins: VCC, GND, IN, NC, COM, NO
   • Description: A relay module used to control the piezo buzzer.
   • Purpose in Circuit: Activates the piezo buzzer when gas is detected.

6. Piezo Buzzer

   • Pins: pin 1, pin 2
   • Description: A buzzer used to produce an audible alarm.
   • Purpose in Circuit: Sounds an alarm when gas is detected.

Wiring Details

MQ-2 Gas Sensor

• GND is connected to the common ground.
• VCC is connected to the 5V output from the 7805 voltage regulator.
• Digital is connected to the IN pin of the 1 Channel Relay 5V.

2x 18650 Batteries

• vcc is connected to pin 1 of the Rocker Switch.
• gnd is connected to the common ground.

Rocker Switch

• Pin 1 is connected to the vcc of the 2x 18650 Batteries.
• Pin 2 is connected to the Vin of the 7805 voltage regulator.

7805 Voltage Regulator

• Vin is connected to pin 2 of the Rocker Switch.
• Gnd is connected to the common ground.
• Vout is connected to the VCC of the 1 Channel Relay 5V and the VCC of the MQ-2 Gas Sensor.

1 Channel Relay 5V

• VCC is connected to the Vout of the 7805 voltage regulator.
• GND is connected to the common ground.
• IN is connected to the Digital pin of the MQ-2 Gas Sensor.
• NO is connected to pin 1 of the Piezo Buzzer.
• COM is connected to the Vout of the 7805 voltage regulator.

Piezo Buzzer

• Pin 1 is connected to the NO pin of the 1 Channel Relay 5V.
• Pin 2 is connected to the common ground.

Code

There is no code provided for this circuit.