Pololu Distance Sensor with Pulse Width Output, 130cm Max

Pololu item #: 4071
Brand: Pololu supply outlook
Status: Active and Preferred 
RoHS 3 compliant

Price break Unit price (US$)
1 17.95
5 16.51
25 15.19

backorders allowed

This small lidar-based distance sensor reports the distance of objects up to about 130 cm (50″) away with a pulsed signal similar to a hobby servo control signal. A digital microcontroller pin can be used to time the length of each high pulse, which encodes the measured distance. The sensor works over an input voltage range of 3.0 V to 5.5 V, and the 0.1″ pin spacing makes it easy to use with standard solderless breadboards and 0.1″ perfboards.

Note: The maximum range of 130 cm is only achievable for high-reflectance objects in good ambient conditions. Lower-reflectivity targets or poor ambient conditions will reduce the maximum range.

Alternatives available with variations in these parameter(s): maximum range Select variant…

 Description Specs (11) Pictures (10) Resources (4) FAQs (0) On the blog (1) 


This compact sensor makes it possible to measure the distance of objects up to about 130 cm (50″) away using a simple digital pulse width interface (similar to a hobby servo control signal). It uses a short-range lidar module to precisely measure how long it takes for emitted pulses of infrared, eye-safe laser light to reach the nearest object and be reflected back, allowing for 1 mm resolution. As long as the sensor is enabled, it takes continuous distance measurements and encodes the ranges as the widths of high pulses, which can then be timed by a microcontroller using a single digital input.

A camera with no IR filter shows the infrared light emitted by a Pololu Digital Distance Sensor.

The relationship between measured distance d (in mm) and pulse width t (in µs) is as follows:

     ``d = (2 text( mm)) / (1 text( µs)) * (t  – 1000 text( µs))``

     ``t = 1000 text( µs) + (1 text( µs)) / (2 text( mm)) * d ``

The timing uncertainty is approximately ±5%. As objects approach the sensor, the output pulse width will approach 1.0 ms, while an object detected at 130 cm will produce a 1.65 ms pulse width. The sensor uses a pulse width of 2.0 ms to indicate no detection. The pulse period T ranges from around 9 ms to 10 ms, depending on the proximity of the detected object.

The maximum detection range depends on object reflectivity and ambient lighting conditions. In our tests, the sensor was able to reliably detect a white sheet of paper out to its maximum range of 130 cm, and it could reliably detect a hand out to around 80 cm away. The following graph shows the measured distances of three units versus their actual distances from a variety of targets at several different ranges:

Please note that while this sensor can detect objects to within about 1 mm of the sensor face, the effective minimum distance it can measure is around 4 cm, so objects closer than 4 cm might result in an inaccurate measurement.


  • Operating voltage: 3.0 V to 5.5 V
  • Current consumption: 30 mA (typical) when enabled, 0.4 mA when disabled
  • Maximum range: approximately 130 cm (50″) (for high-reflectivity targets in good ambient conditions; lower-reflectivity targets or poor ambient conditions will reduce the maximum detection range)
  • Minimum range: 4 cm (for accurate measurement); < 1 mm (for detection)
  • Update rate: 100 Hz to 110 Hz (10 ms to 9 ms period)
  • Field of view (FOV): 15° typical; can vary with object reflectance and ambient conditions
  • Output type: digital pulse width
  • Dimensions: 0.85″ × 0.35″ × 0.136″ (21.6 × 8.9 × 3.5 mm); see the dimension diagram (193k pdf) for more information
  • Weight: 0.014 oz (0.4 g)

Using the sensor

Important note: This product might ship with a protective liner covering the sensor IC. The liner must be removed for proper sensing performance.

Three connections are necessary to use this module: VIN, GND, and OUT. These pins are accessible through a row of 0.1″-pitch through holes, which work with standard 0.1″ (2.54 mm) male headers and 0.1″ female headers (available separately). The VIN pin should be connected to a 3 V to 5.5 V source, and GND should be connected to 0 volts. The sensor outputs its digital pulses on the OUT pin. The low level of the pulses is 0 V, and the high level is VIN. A red LED on the back side of the board also lights whenever an object is detected (the closer the object, the brighter the LED).

The board has an optional ENABLE pin that can be driven low to put it into a low-power state that consumes approximately 0.4 mA. This pin can be accessed through a via or its neighboring surface-mount pad on the back side labeled “EN” on the silkscreen. The ENABLE pin is pulled up to VIN, enabling the sensor by default.

The board has one mounting hole intended for use with #2 or M2 screws.

Arduino program for reading pulse width output

This is a simple Arduino sketch that reads the output of the Pololu Distance Sensor with Pulse Width Output, 130cm Max and displays the measured distance in millimeters.

// Example Arduino program for reading the Pololu Distance Sensor with Pulse Width Output, 130cm Max

// Change this to match the Arduino pin connected to the sensor's OUT pin.
const uint8_t sensorPin = 2;

void setup()

void loop()
  int16_t t = pulseIn(sensorPin, HIGH);

  if (t == 0)
    // pulseIn() did not detect the start of a pulse within 1 second.
  else if (t > 1850)
    // No detection.
    // Valid pulse width reading. Convert pulse width in microseconds to distance in millimeters.
    int16_t d = (t - 1000) * 2;

    // Limit minimum distance to 0.
    if (d < 0) { d = 0; } 
    Serial.println(" mm");

micro:bit MakeCode program for reading pulse width output

We have also created a MakeCode example program for the BBC micro:bit single-board computer that demonstrates how to read and convert the output of the Pololu Distance Sensor with Pulse Width Output, 300cm Max. The program’s output can be viewed in the MakeCode device console, which also plots the readings on a graph. You can open the program in the micro:bit MakeCode editor by clicking this link or the picture below.

Jumper settings (irs17a)

The board features four surface-mount configuration jumpers that determine its operation mode. Different versions of the Pololu Digital Distance Sensors ship with the appropriate jumpers pre-populated with 0 Ω resistors. These resistors can be desoldered from the populated spots or solder bridges can be added across the unpopulated spots to convert one sensor version into another. This sensor can be converted into any other irs17a version as listed in the following table. (For more information about how the different output types work, see the product pages for representative versions.)

Item # Description Maximum
Hysteresis Resolution Minimum
#4066 Digital output, 25cm 25 cm 50 mm - 100 Hz 0000
#4067 Digital output, 50cm 50 cm 50 mm - 100 Hz 0001
Digital output, 75cm 75 cm 50 mm - 100 Hz 0010
#4069 Digital output, 100cm 100 cm 50 mm - 100 Hz 0011
Digital output, any detect ~130 cm - - 100 Hz 0100
#4071 Pulse width output, 130cm max ~130 cm - 1 mm
(= 0.5 µs)
100 Hz
(110 Hz max)
Digital output,125cm 125 cm 50 mm - 30 Hz 1000
Digital output,150cm 150 cm 50 mm - 30 Hz 1001
Digital output,175cm 175 cm 50 mm - 30 Hz 1010
#4077 Digital output, 200cm 200 cm 50 mm - 30 Hz 1011
Digital output, any detect ~300 cm - - 30 Hz 1100
#4079 Pulse width output, 300cm max ~300 cm - 2 mm
(= 0.5 µs)
30 Hz
(33 Hz max)

* Effective range depends on object reflectivity and ambient lighting conditions.

Item numbers in this table indicate versions that we offer for sale as standard products, but we can manufacture the other versions on demand (or even make sensors with custom firmware for you). If you are interested in customization, please contact us.

The Pololu Digital Distance Sensor family

We have several different versions of Pololu Digital Distance Sensors, all with the same dimensions and pinout:

Digital output
(does not provide distance measurement)
Sensor Maximum
PCB ID Price
#4050: Digital output, 5cm 5 cm < 5 mm 145 Hz 0000 irs16a $12.95
#4052: Digital output, 10cm 10 cm < 5 mm 115 Hz 0010
#4054: Digital output, 15cm 15 cm < 5 mm 95 Hz 0100
#4066: Digital output, 25cm 25 cm < 1 mm 100 Hz 0000 irs17a $17.95
#4067: Digital output, 50cm 50 cm < 1 mm 100 Hz 0001
#4069: Digital output, 100cm 100 cm < 1 mm 100 Hz 0011
#4077: Digital output, 200cm 200 cm < 1 mm 30 Hz 1011

Pulse width output
(provides distance measurement)
Sensor Maximum
Resolution Minimum
PCB ID Price
#4064: Pulse width output, 50cm max ~50 cm 1 cm 3 mm 50 Hz 1110 irs16a $12.95
#4071: Pulse width output, 130cm max ~130 cm 4 cm 1 mm 100 Hz 0101 irs17a $17.95
#4079: Pulse width output, 300cm max ~300 cm 4 cm 2 mm 30 Hz 1101

1 Effective range depends on object reflectivity and ambient lighting conditions.
2 Objects closer than the minimum distance can still be detected, but the measured distance might be inaccurate. The minimum detection range is < 5 mm for irs16a boards and < 1 mm for irs17a boards.

These are the output graphs for the digital output versions that just report if an object is in their detection range:

The output graph is a bit different for the versions that use a pulse width to encode the measured distance. The output for these versions is similar to hobby servo control signals and is shown below as a function of time:

Comparison to Sharp Digital Distance Sensors

These Pololu Digital Distance Sensors have the same form factor and pinout as our carrier boards for the Sharp/Socle GP2Y0D8x digital distance sensors. They are available in the same 5 cm, 10 cm, and 15 cm ranges, in addition to longer ranges of up to several meters. This means they can be used as replacements for these older modules, which are based on sensors from Sharp/Socle that are no longer in production, and the longer-range versions can serve as upgrades that provide enhanced detection and measurement capabilities. The sensors on these newer units are much thinner than the Sharp modules, so the zero-range point is approximately 7 mm closer to the PCB, and the beam angle of the newer units is wider. The pictures below show side-by-side comparisons of the two:

People often buy this product together with:

Pololu Distance Sensor with Pulse Width Output, 50cm Max Pololu Distance Sensor with Pulse Width Output, 50cm Max
Pololu Distance Sensor with Pulse Width Output, 300cm Max Pololu Distance Sensor with Pulse Width Output, 300cm Max

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0.100" (2.54 mm) Breakaway Male Header: 1×40-Pin, Straight, Black
0.100" (2.54 mm) Breakaway Male Header: 1×40-Pin, Right Angle
0.1" (2.54mm) Crimp Connector Housing: 1x3-Pin 25-Pack
0.100" (2.54 mm) Female Header: 1x3-Pin, Straight

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