QTR-8RC Reflectance Line Follower Sensor Array (8 Channel)

The QTR-8RC Reflectance Sensor Array is a compact module featuring eight infrared (IR) LED and phototransistor pairs mounted on a single board. These pairs are spaced at 0.375 inches (9.525 mm) intervals, making it ideal for detecting lines or edges in robotic applications. The sensor works by emitting IR light and measuring the amount reflected back from a surface—more reflection (e.g., from a white surface) results in faster capacitor discharge times, while less reflection (e.g., from a black line) takes longer. This RC (resistor-capacitor) version outputs analog signals that can be read via timing measurements on microcontroller I/O pins, eliminating the need for ADC resources. The board includes a MOSFET for controlling the LEDs, allowing them to be turned off to save power or modulated via PWM for brightness adjustment.

Features

• Eight IR LED/phototransistor pairs arranged in series to reduce current draw.
• MOSFET-controlled LEDs for on/off functionality, power conservation, and PWM-based brightness control.
• Digital output via timed pulses for high sensitivity and parallel sensor reading.
• Voltage flexibility with staged current-limiting resistors for 3.3V or 5V operation.
• Breakable design for creating smaller sensor arrays.
• No ADC required, compatible with most microcontrollers for efficient integration.
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Specifications

ParameterValue/DetailsDimensions66.5 mm x 16.5 mm x 3.5 mm

Operating Voltage3.3 V to 5.0 V

Output Format8 analog I/O signalsSensor

Spacing0.375″ (9.525 mm) pitch

Optimal Sensing Distance0.125″ (3 mm)

Max Recommended Distance0.375″ (9.5 mm)

Weight6 g

Applications

• Line-Following Robots
• Proximity Sensing
• Edge Detection
• General Reflectance Tasks
• Educational Projects