QTR-8A Reflectance Sensor Array

QTR-8A Reflectance Sensor Array info

QTR-8A Reflectance Sensor Array is intended as a line sensor, but it can be used as a general-purpose proximity or reflectance sensor. The module is a convenient carrier for eight IR emitter and receiver (phototransistor) pairs evenly spaced at intervals of 0.375" (9.525 mm). Each phototransistor is connected to a pull-up resistor to form a voltage divider that produces an analog voltage output between 0 V and VIN (which is typically 5 V) as a function of the reflected IR. Lower output voltage is an indication of greater reflection.

The outputs are all independent, but the LEDs are arranged in pairs to halve current consumption. The LEDs are controlled by a MOSFET with a gate normally pulled high, allowing the LEDs to be turned off by setting the MOSFET gate to a low voltage. Turning the LEDs off might be advantageous for limiting power consumption when the sensors are not in use or for varying the effective brightness of the LEDs through PWM control.

QTR-8A Reflectance Sensor Array - General Specifications

• Line sensor
• General purpose proximity or reflectance sensor
• 8 IR emitter and receiver pairs
• Maximum 6mm sensing range

QTR-8A Reflectance Sensor Array - Technical Specifications

• Dimensions: 2.95" x 0.5" x 0.125" (without header pins installed)
• Operating voltage: 3.3-5.0 V
• Supply current: 100 mA
• Output format: 8 analog voltages
• Output voltage range: 0 V to supplied voltage
• Optimal sensing distance: 0.125" (3 mm)
• Maximum recommended sensing distance: 0.25" (6 mm)
• Weight without header pins: 0.11 oz (3.09 g)

Videos

Documents

QTR-8A and QTR-8RC Reflectance Sensor Array User’s Guide:

https://www.pololu.com/docs/0J12

Pololu QTR Reflectance Sensor Application Note:

https://www.pololu.com/docs/0J13

Pololu AVR C/C++ Library User’s Guide:

https://www.pololu.com/docs/0J20

Arduino Library for the Pololu QTR Reflectance Sensors:

https://www.pololu.com/docs/0J19

Pololu AVR Library Command Reference:

https://www.pololu.com/docs/0J18

References

Pololu Web Site: https://www.pololu.com/product/960