Introduction
In a world when there’s so much chaos around, we are always at a risk of getting trapped y a fire which can cause harm to the environment and so humans. The chances of caught by fire are much higher if we don’t take any safety-related measures. hence, There should always have a smoke detector that indicates fire so that people would take immediate actions to prevent them from any kind of loss or damage. So, In this tutorial, we are going to ” Simple Smoke Detector Alarm Circuit using MQ02 ” This circuit is easy and can be quickly made, it has an MQ02 smoke sensor that detects any fire, smoke, and gas. Hence, it uses the buzzer and LED for indication. The circuit requires very few components which makes it more affordable.
An Overview about MQ-02 Sensor
The sensor has included two layers of steel. The output is taken as the voltage which depends on the concentration of the gases. In different words, voltage is directly proportional to the gas concentration of the environment. The lower the concentration, the lower would be the voltage. Similarly, when the concentration is greater, the voltage would be greater. The MQ02 sensor can quickly detect Alcohol, propane, LPG, hydrogen, and methane. The operating voltage of the sensor is about 5V. Since it requires a warm-up, therefore, it has a preheat duration of 20 seconds. Moreover, it can be used both as a digital or analog sensor. Also, the sensitivity of the digital pin can be changed by the given potentiometer.
Hardware Required
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Smoke Gas Sensor | MQ-02 | 1 |
| 2. | Dual Operational Amplifier IC | LM358 | 1 |
| 3. | LED | – | 1 |
| 4. | Buzzer | – | 1 |
| 5. | Potentiometer | 10KΩ | 1 |
| 6. | Capacitor | 0.1µF | 1 |
| 7. | Resistor | 10KΩ, 100Ω | 1, 1 |
| 8. | Battery | 6V | 1 |
Circuit Diagram
Working Explanation
This Simple Smoke Detector Alarm Circuit uses the MQ02 sensor, having three pairs called A, B, and HB pins are for the supply voltage, while A and B are interchangeable. To use this MQ02 sensor directly connect three pins at one side to the bias voltage. For example, we have connected B1, B2, and HB to that bias supply voltage. . After that, connect the HA pin to the negative terminal of the battery and connect A1 and A2 to the non-inverting pins of an operational amplifier, that is LM358.
Now, if there is any smoke, fire, gas, it would be detected by the MQ02 sensor, the sensing resistance value got changes. Hence, the amplifier increase that output which drives the load. In our case, the loads are the buzzer and the LED. The LED starts to glow while the buzzer starts beeping in any unusual conditions. And, this is how the circuit works.
Application and Uses
- It can be used in air quality monitoring systems.
- Moreover, it may be utilized in gas leak alarm devices.
- Also in the fire detecting devices.
- Residential gas leakage detectors can also use this circuit.
- industrial Combustible detector may employ this circuit for their use.
- Portable gas detectors are also one of its applications.
- Hence, you can utilize this in safety maintenance devices.
- Hence, it can be used in every safety maintenance device.
