1. Introduction

Kitchen gas leak detectors and industrial safety monitors both rely on exactly this kind of sensor to detect a dangerous buildup of combustible or harmful gas and raise an audible alarm before the situation becomes hazardous. In this experiment, an MQ-series gas sensor module is wired to the STM32F070RB's analog to digital converter, and when the detected gas concentration crosses a set threshold, an active buzzer sounds an alarm.

2. Scope

This experiment covers reading an MQ-series gas sensor's analog output, comparing the reading against a configurable alarm threshold, and driving an active buzzer to sound an audible alert when that threshold is exceeded. This combines analog sensor reading with a genuine safety-relevant threshold response.

3. Prerequisite

3.1 Hardware

• STM32 Nucleo-F070RB development board

• MQ-series gas sensor module, such as an MQ-2 or MQ-135, with analog output

• Active buzzer module

• Breadboard and jumper wires

• Micro-USB cable

• PC with PuTTY

3.2 Software

• STM32CubeMX (standalone)

• STM32CubeIDE

• ST-LINK USB driver

• PuTTY, or an equivalent serial terminal application