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Single-Channel QTR Reflectance Sensors
These reflectance sensors feature IR emitter/phototransistor modules that are well suited for applications that require detection of changes in reflectivity. This change in reflectivity can be due to a color change at a fixed distance, such as when sensing a black line on a white background, as well as due to a change in the distance to or presence of an object in front of the sensor. All of the products in this category are single-channel sensors that can be arranged in whatever spacing or configuration is needed; we also have arrays with different sensor counts and densities available.
Single-channel QTR sensors with dimmable emitters 2.9 V to 5.5 V; 30 mA max LED current(1) |
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Sensor type |
Max board current(2) |
Optimal range |
Max range |
Board size | Connector | Output type |
Name | 1-piece price |
---|---|---|---|---|---|---|---|---|
QTR | 32 mA | 5 mm | 30 mm | 5.0 × 20.0 × 2.5 mm | — | analog | QTR-HD-01A | $3.25 |
RC (digital) | QTR-HD-01RC | $3.25 | ||||||
7.5 × 20.0 × 2.5 mm | — | analog | QTR-MD-01A | $2.75 | ||||
RC (digital) | QTR-MD-01RC | $2.75 | ||||||
8.1 × 15.2 × 5.5 mm | side-entry JST SH-type |
analog | QTR-MD-01A-S | $3.95 | ||||
RC (digital) | QTR-MD-01RC-S | $3.95 | ||||||
QTRX | 5 mA | 10 mm | 30 mm | 5.0 × 20.0 × 3.0 mm | — | analog | QTRX-HD-01A | $3.75 |
RC (digital) | QTRX-HD-01RC | $3.75 | ||||||
7.5 × 20.0 × 3.0 mm | — | analog | QTRX-MD-01A | $3.25 | ||||
RC (digital) | QTRX-MD-01RC | $3.25 | ||||||
8.1 × 15.2 × 6.0 mm | side-entry JST SH-type |
analog | QTRX-MD-01A-S | $4.29 | ||||
RC (digital) | QTRX-MD-01RC-S | $4.29 | ||||||
QTRXL | 32 mA | 20 mm | 80 mm | 5.0 × 20.0 × 3.0 mm | — | analog | QTRXL-HD-01A | $3.75 |
RC (digital) | QTRXL-HD-01RC | $3.75 | ||||||
7.5 × 20.0 × 3.0 mm | — | analog | QTRXL-MD-01A | $3.37 | ||||
RC (digital) | QTRXL-MD-01RC | $3.37 | ||||||
8.1 × 15.2 × 6.0 mm | side-entry JST SH-type |
analog | QTRXL-MD-01A-S | $4.29 | ||||
RC (digital) | QTRXL-MD-01RC-S | $4.29 | ||||||
1 Can be dynamically reduced to any of 32 available dimming levels. 2 With all LEDs on at max brightness setting. |
Note: All of the boards with black PCBs are versions introduced in 2018 with integrated LED drivers that offer dimmable brightness control independent of the 2.9 V to 5.5 V supply voltage. The boards with red and green PCBs are our original QTR sensors without LED drivers, so the emitter brightness is a function of the supply voltage.
Compare all products in this category
Products in category “Single-Channel QTR Reflectance Sensors”
Pololu item #: 4101 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
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sensors | size (mm) |
output | max current | optimal range |
|
---|---|---|---|---|---|
LED | board | ||||
1 | 5.0 × 20.0 | RC (digital) | 30 mA | 32 mA | 5 mm |
This IR LED/phototransistor pair 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 a traditional-style QTR sensor without lenses.
Pololu item #: 4141 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
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sensors | size (mm) |
output | max current | optimal range |
|
---|---|---|---|---|---|
LED | board | ||||
1 | 7.5 × 20.0 | RC (digital) | 30 mA | 32 mA | 5 mm |
This IR LED/phototransistor pair 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 a traditional-style QTR sensor without lenses.
Pololu item #: 4140 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
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sensors | size (mm) |
output | max current | optimal range |
connector | |
---|---|---|---|---|---|---|
LED | board | |||||
1 | 8.1 × 15.2 | RC (digital) | 30 mA | 32 mA | 5 mm | side-entry |
This sensor uses an IR LED and a phototransistor to measure the light reflected from nearby surfaces. It operates from 2.9–5.5 V, with dimmable brightness control independent of the supply voltage. The optimal range is <5 mm, but it can detect high-reflectance objects out to around 30 mm. This version features a traditional-style QTR sensor without lenses and a connector that works with our 4-pin JST SH-style cables (compatible with SparkFun’s Qwiic and Adafruit’s STEMMA QT cables, but the interface is not I²C).
Pololu item #: 4201 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
|
---|---|---|---|---|---|
LED | board | ||||
1 | 5.0 × 20.0 | analog | 30 mA | 32 mA | 5 mm |
This IR LED/phototransistor pair 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 a traditional-style QTR sensor without lenses.
Pololu item #: 4241 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
|
---|---|---|---|---|---|
LED | board | ||||
1 | 7.5 × 20.0 | analog | 30 mA | 32 mA | 5 mm |
This IR LED/phototransistor pair 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 a traditional-style QTR sensor without lenses.
Pololu item #: 4240 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
connector | |
---|---|---|---|---|---|---|
LED | board | |||||
1 | 8.1 × 15.2 | analog | 30 mA | 32 mA | 5 mm | side-entry |
This sensor uses an IR LED and a phototransistor to measure the light reflected from nearby surfaces. It operates from 2.9–5.5 V, with dimmable brightness control independent of the supply voltage. The optimal range is <5 mm, but it can detect high-reflectance objects out to around 30 mm. This version features a traditional-style QTR sensor without lenses and a connector that works with our 4-pin JST SH-style cables (compatible with SparkFun’s Qwiic and Adafruit’s STEMMA QT cables, but the interface is not I²C).
Pololu item #: 4301 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
|
---|---|---|---|---|---|
LED | board | ||||
1 | 5.0 × 20.0 | RC (digital) | 3.5 mA | 5 mA | 10 mm |
This IR LED/phototransistor pair 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 a high-performance, low-current QTRX sensor with lenses.
Pololu item #: 4341 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
|
---|---|---|---|---|---|
LED | board | ||||
1 | 7.5 × 20.0 | RC (digital) | 3.5 mA | 5 mA | 10 mm |
This IR LED/phototransistor pair 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 a high-performance, low-current QTRX sensor with lenses.
Pololu item #: 4340 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
QTRX-MD-01RC-S Reflectance Sensor: 1-Channel, 8mm Wide, RC Output, Low Current, Side-Entry Connector
sensors | size (mm) |
output | max current | optimal range |
connector | |
---|---|---|---|---|---|---|
LED | board | |||||
1 | 8.1 × 15.2 | RC (digital) | 3.5 mA | 5 mA | 10 mm | side-entry |
This sensor uses an IR LED and a phototransistor to measure the light reflected from nearby surfaces. It operates from 2.9–5.5 V, with dimmable brightness control independent of the supply voltage. The optimal range is <5 mm, but it can detect high-reflectance objects out to around 30 mm. This version features a high-performance, low-current QTRX sensor with lenses and a connector that works with our 4-pin JST SH-style cables (compatible with SparkFun’s Qwiic and Adafruit’s STEMMA QT cables, but the interface is not I²C).
Pololu item #: 4401 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
|
---|---|---|---|---|---|
LED | board | ||||
1 | 5.0 × 20.0 | analog | 3.5 mA | 5 mA | 10 mm |
This IR LED/phototransistor pair 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 a high-performance, low-current QTRX sensor with lenses.
Pololu item #: 4441 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
|
---|---|---|---|---|---|
LED | board | ||||
1 | 7.5 × 20.0 | analog | 3.5 mA | 5 mA | 10 mm |
This IR LED/phototransistor pair 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 a high-performance, low-current QTRX sensor with lenses.
Pololu item #: 4440 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
connector | |
---|---|---|---|---|---|---|
LED | board | |||||
1 | 8.1 × 15.2 | analog | 3.5 mA | 5 mA | 10 mm | side-entry |
This sensor uses an IR LED and a phototransistor to measure the light reflected from nearby surfaces. It operates from 2.9–5.5 V, with dimmable brightness control independent of the supply voltage. The optimal range is <5 mm, but it can detect high-reflectance objects out to around 30 mm. This version features a high-performance, low-current QTRX sensor with lenses and a connector that works with our 4-pin JST SH-style cables (compatible with SparkFun’s Qwiic and Adafruit’s STEMMA QT cables, but the interface is not I²C).
Pololu item #: 4501 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
|
---|---|---|---|---|---|
LED | board | ||||
1 | 5.0 × 20.0 | RC (digital) | 30 mA | 32 mA | 20 mm |
This IR LED/phototransistor pair 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 80 mm. This version features a high-performance QTRXL sensor with lenses and a high-brightness emitter for extra-long range.
Pololu item #: 4541 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
|
---|---|---|---|---|---|
LED | board | ||||
1 | 7.5 × 20.0 | RC (digital) | 30 mA | 32 mA | 20 mm |
This IR LED/phototransistor pair 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 80 mm. This version features a high-performance QTRXL sensor with lenses and a high-brightness emitter for extra-long range.
Pololu item #: 4540 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
QTRXL-MD-01RC-S Reflectance Sensor: 1-Channel, 8mm Wide, RC Output, Long Range, Side-Entry Connector
sensors | size (mm) |
output | max current | optimal range |
connector | |
---|---|---|---|---|---|---|
LED | board | |||||
1 | 8.1 × 15.2 | RC (digital) | 30 mA | 32 mA | 20 mm | side-entry |
This sensor uses an IR LED and a phototransistor to measure the light reflected from nearby surfaces. It operates from 2.9–5.5 V, with dimmable brightness control independent of the supply voltage. The optimal range is <5 mm, but it can detect high-reflectance objects out to around 80 mm. This version features a high-performance QTRXL sensor, with lenses and a high-brightness emitter for extra-long range, and a connector that works with our 4-pin JST SH-style cables (compatible with SparkFun’s Qwiic and Adafruit’s STEMMA QT cables, but the interface is not I²C).
Pololu item #: 4601 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
|
---|---|---|---|---|---|
LED | board | ||||
1 | 5.0 × 20.0 | analog | 30 mA | 32 mA | 20 mm |
This IR LED/phototransistor pair 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 80 mm. This version features a high-performance QTRXL sensor with lenses and a high-brightness emitter for extra-long range.
Pololu item #: 4641 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
|
---|---|---|---|---|---|
LED | board | ||||
1 | 7.5 × 20.0 | analog | 30 mA | 32 mA | 20 mm |
This IR LED/phototransistor pair 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 80 mm. This version features a high-performance QTRXL sensor with lenses and a high-brightness emitter for extra-long range.
Pololu item #: 4640 | |
Brand: Pololu | supply outlook |
Status: Active and Preferred | |
![]() |
sensors | size (mm) |
output | max current | optimal range |
connector | |
---|---|---|---|---|---|---|
LED | board | |||||
1 | 8.1 × 15.2 | analog | 30 mA | 32 mA | 20 mm | side-entry |
This sensor uses an IR LED and a phototransistor to measure the light reflected from nearby surfaces. It operates from 2.9–5.5 V, with dimmable brightness control independent of the supply voltage. The optimal range is <5 mm, but it can detect high-reflectance objects out to around 80 mm. This version features a high-performance QTRXL sensor, with lenses and a high-brightness emitter for extra-long range, and a connector that works with our 4-pin JST SH-style cables (compatible with SparkFun’s Qwiic and Adafruit’s STEMMA QT cables, but the interface is not I²C).
Pololu item #: 2458 | |
Brand: Pololu | |
Status: Active and Preferred | |
![]() |
The QTR-1A reflectance sensor carries a single infrared LED and phototransistor pair in an inexpensive, tiny 0.5" x 0.3" module that can be mounted almost anywhere and is great for edge detection and line following. The reflectance measurement is output as an analog voltage. This sensor is sold in packs of two units.
Pololu item #: 2459 | |
Brand: Pololu | |
Status: Active and Preferred | |
![]() |
The QTR-1RC reflectance sensor carries a single infrared LED and phototransistor pair in an inexpensive, tiny 0.5" x 0.3" module that can be mounted almost anywhere and is great for edge detection and line following. The output is designed to be measured by a digital I/O line. This sensor is sold in packs of two units.
Pololu item #: 2454 | |
Brand: Pololu | |
Status: Active and Preferred | |
![]() |
The QTR-L-1A reflectance sensor incorporates a right-angle infrared LED and a right-angle phototransistor in an inexpensive, tiny 0.35″ × 0.3″ module that can be mounted almost anywhere and is great for edge detection and line following. The reflectance measurement is output as an analog voltage. This sensor is sold in packs of two units.
Pololu item #: 2455 | |
Brand: Pololu | |
Status: Active and Preferred | |
![]() |
The QTR-L-1RC reflectance sensor incorporates a right-angle infrared LED and a right-angle phototransistor in an inexpensive, tiny 0.35″ × 0.3″ module that can be mounted almost anywhere and is great for edge detection and line following. The output is designed to be measured by a digital I/O line. This sensor is sold in packs of two units.
Coupon Discount
QTRSINTRO: Get 15% off one or more items from category Single-Channel QTR Reflectance Sensors (limit 5 per item). This offer is valid through 31 Oct 2025.