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QTRX-MD-03A Reflectance Sensor Array: 3-Channel, 8mm Pitch, Analog Output, Low Current


This array of IR LED/phototransistor pairs is great for precisely identifying changes in reflectance (like line detection). It operates from 2.9 V to 5.5 V and offers dimmable brightness control independent of the supply voltage.

In general, the closer the object, the higher the contrast between light and dark readings, but high-reflectance objects are generally detectable out to around 30 mm. This version features high-performance, low-current QTRX sensors with lenses.



  • Dimensions: 21.0 × 20.0 × 3.0 mm 
  • Operating voltage: 2.9 V to 5.5 V
  • Sensor type: QTRX
  • Sensor count: 3
  • Sensor pitch: 8 mm
  • Full-brightness LED current: 3.5 mA (independent of supply voltage)
  • Max board current: 9 mA
  • Output format: analog voltages (0 V to VCC)
  • Optimal sensing distance: 10 mm
  • Maximum recommended sensing distance: 30 mm
  • Weight: 1.1 g
pitch × sensorssize
outputmax currentoptimal
8 mm × 3 21.0 × 20.0 analog 3.5 mA 9 mA 10 mm

General specifications

Maximum range: 30 mm
Optimal range: 10 mm
Minimum operating voltage: 2.9 V
Maximum operating voltage: 5.5 V
LED current: 3.5 mA1
Peak wavelength: 940 nm
Maximum current draw: 9 mA2
Sensor type: QTRX
Sensor pitch: 8.0 mm
Sensor count: 3
Output type: A (analog voltages)

Identifying markings

PCB dev codes: irs25j3
Other PCB markings: 0J113813


Can be dynamically reduced to any of 32 available dimming levels.
With all LEDs on at max brightness setting.
Note: this does not differentiate between the A and RC output types.


Pololu QTR Reflectance Sensor Application Note (Printable PDF

Arduino Library for the Pololu QTR Reflectance Sensors (Printable PDF