Introduction

Autonomous line-following robots, a common project in robotics competitions, rely entirely on exactly this kind of sensing to know whether they are still tracking their intended path. In this experiment, an infrared line-tracking sensor module is wired to the STM32F070RB as a simple digital input, and the microcontroller reports over UART whether it currently detects the line beneath it.

2. Scope

This experiment covers understanding how surface reflectivity differences, a dark line against a light background or the reverse, are detected using infrared reflectance sensing, and reading the sensor's digital output. This is a straightforward digital sensor reading, forming the fundamental building block a full line-following robot would extend into a multi-sensor array.

3. Prerequisite

3.1 Hardware

• STM32 Nucleo-F070RB development board

• IR line-tracking sensor module, single channel, digital output

• A test surface with clear light and dark contrast, such as a black line drawn on white paper

• 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