Exhaust Monitoring System

The Exhaust Monitoring System is a portable or fixed device that continuously checks air quality around engines and exhaust sources. It focuses on detecting:

1. Combustible gases like LPG, propane, methane, hydrogen, and fuel vapors
2. Air-quality pollutants like ammonia, benzene, alcohol vapor, smoke, and general polluted air

It uses two common semiconductor gas sensors:

1. MQ2 – for smoke and combustible gases near the exhaust source
2. MQ135 – for general air quality where people are working

The system is fully analog, meaning it does not use a microcontroller. Instead, it relies on simple and reliable electronic components to trigger alarms when gas levels become dangerous.

Gas Sensor:

1. MQ2 or MQ135

ICs:

1. U1 – LM358 (dual op-amp)
2. U3 – NE555 timer

Potentiometers:

1. 10 kΩ × 2 (sensitivity adjustment)

Resistors:

1. R13 – 10 kΩ
2. R12 – 100 kΩ
3. R3 – 1 kΩ

Capacitors:

1. C1 – 0.1 µF (100 nF)
2. C2 – 10 µF / 16 V
3. C9 – 100 µF / 16 V

Transistor:

1. Q2 – BC547 or 2N2222 (NPN)

LEDs:

1. LED1 – Red LED (Power)
2. LED2 – Red or Green LED (Alarm)
3. Series resistor for each LED – 330 Ω

Buzzer:

1. Active buzzer, 5–12 V

Other Items:

1. PCB
2. On/Off switch
3. DC power supply: 5–12 V
4. Wires
5. Enclosure
6. Screws and spacers
7. Solder

This project is about designing and building an Exhaust Monitoring System. The main aim is to detect harmful exhaust gases and poor air quality in places like garages, workshops, and engine rooms. Exhaust gases can be dangerous to health, so early detection is very important.

The system uses gas sensors to sense smoke and polluted air. When the gas level becomes high, the system gives an alarm using an LED and a buzzer. This helps people know there is danger and take action quickly.

The project is simple, low-cost, and fully analog. It is mainly made for learning, testing, and basic safety monitoring.

In this step, the battery and power switch are connected to the PCB. This allows the system to be turned ON and OFF safely. Proper connection is important to protect the circuit and make sure it works correctly.

In this step, all parts are placed inside the enclosure. This protects the circuit from dust, damage, and touching. It also makes the project neat and easy to use.

In this step, the project is fully completed and checked. All parts are tested again to make sure they work correctly. The system is now ready to use for monitoring exhaust and air quality.