DIY Carbon Monoxide Home Alert System with Arduino Uno, MQ-7 Sensor & GSM SMS Alerts

Every part needed, pre-tested for compatibility, with an AI build companion trained on this exact project. Shipped from Bengaluru in 3-5 days.

Carbon monoxide (CO) is odourless, colourless, and lethal—especially in Indian kitchens using gas stoves, water heaters, or during winter with room heaters. This kit lets you build a real-time CO home alert system that not only sounds a loud local alarm but also activates an exhaust fan and sends an SMS warning to your phone when gas concentrations cross safe limits. Unlike cloud-dependent smart alarms, this Arduino-based solution works independently using a SIM800L GSM module, ensuring your family is alerted even without Wi-Fi.

What You'll Build

A stand-alone carbon monoxide safety device. The MQ-7 sensor continuously measures CO levels; the Arduino Uno reads the analog output, compares it to a calibrated threshold, and upon detection of a dangerous concentration, triggers three actions: the active buzzer sounds an audible alarm, the 5V relay switches on a connected exhaust fan (or any mains appliance) to ventilate the space, and the SIM800L GSM module sends a pre-configured SMS alert to a mobile number. The entire circuit runs on a single 12V DC power adapter via the LM2596 buck converter, making it deployable in a kitchen, boiler room, or garage.

What You'll Learn

• Interpret analog output of the MQ-7 CO sensor and map it to ppm using the datasheet curves.
• Configure Arduino ADC to read gas concentration and implement calibration routines.
• Send SMS messages using AT commands with the SIM800L GSM module.
• Drive a 5V relay to safely control AC-powered appliances like exhaust fans.

Kit Contents