🔍 QTR-8RC Reflectance Sensor Array – 8-Channel IR Line Sensor (RC Version)
The QTR-8RC is a high-performance reflectance sensor array designed to detect contrast between surfaces, such as black lines on white backgrounds. Ideal for line-following robots, edge detection, or maze-solving applications, this sensor array uses infrared LEDs and phototransistors arranged in a straight line for precise, fast, and flexible tracking.
✅ Key Features:
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8 Individual Sensors – Each with its own IR emitter and phototransistor pair.
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Digital Output (RC Decay Time) – Measures reflectance via charge/discharge timing (RC time).
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High-Speed Detection – Works well even at high robot speeds.
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Adjustable Brightness – Through included resistor or PWM control.
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Compact Form Factor – Can be split into smaller units (e.g., 2× QTR-4RC or custom-sized arrays).
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Works with 3.3V or 5V logic – Ideal for Arduino, ESP32, STM32, Raspberry Pi, etc.
📦 Technical Specifications:
| Parameter | Value |
|---|---|
| Number of Sensors | 8 |
| Operating Voltage | 5 V (recommended), 3.3V compatible |
| Output Type | Digital (RC timing) |
| Output Format | Reflectance measured via time delay |
| Typical Sensing Range | ~3 mm (depends on surface) |
| IR LED Wavelength | ~940 nm |
| Array Width | ~75 mm |
| Pin Header Type | 2.54 mm standard (included) |
🧠 How It Works:
The QTR-8RC doesn’t output analog voltages. Instead, each output pin behaves like a capacitor discharge timer:
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Charge the sensor line (set high).
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Switch to input and measure how long it takes to go LOW.
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Faster discharge = more reflectance (white surface), slower = less (black line).
Perfect for timing-sensitive microcontrollers like Arduino or STM32 that can measure pulse durations accurately.
🎯 Applications:
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Line-following robots
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Maze solvers
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Edge detection
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Surface tracking
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PID-based autonomous navigation
