QTR 8 Bit Line Hunter Sensor Array Module

Key Specifications:

• Sensors: 8 IR emitter/phototransistor pairs.
• Operating Voltage: 3.3V to 5V DC.
• Output: 8 digital I/O signals (timed high pulse).
• Sensing Distance: Optimal ~3mm (0.125″), Max ~9.5mm (0.375″).
• Pitch: 0.375″ (9.525 mm) between sensors.
• Current Draw: ~100 mA (with LEDs on).
• Dimensions: ~2.95″ x 0.5″ (75mm x 13mm).
• Features: Onboard LEDs, optional LED control via MOSFET, adjustable sensitivity via potentiometer.
• Interface: Resistor-Capacitor (RC) circuit for timing-based reads.

How it Works:

• Each sensor charges an output pin high, then measures the decay time as the phototransistor discharges it through a resistor.
• A shorter decay time (faster fall to low) indicates higher reflectance (white surface), while a longer time indicates lower reflectance (black line/surface).
• This timed measurement (pulse width) is read by a microcontroller’s digital pin.