Gas Leak SMS Alert

Overview

The MQ-2 warms up and reports gas level on its analog pin. A SIM800L sends a text message, so the alert works even when there is no WiFi.

Build Steps

1. 1

   Warm up the MQ-2

   Let the sensor heat for a few minutes and log normal room readings so you can pick a sensible threshold.

2. 2

   Power the SIM800L

   Feed it about 4.0 V from an LM2596 with a 1000 µF capacitor close by; its 2 A peaks will reset a weak supply.

3. 3

   Wire serial

   SIM800L TX/RX to software-serial pins and test with a manual AT command before connecting the sensor.

4. 4

   Send the alert

   When the gas reading passes the threshold, send an SMS, then rate-limit so it does not text repeatedly.