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Pololu Distance Sensor with Pulse Width Output, 50cm Max

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Pololu Distance Sensor with Pulse Width Output, 50cm Max

SKU: POLOLU-4064 Brand: Pololu

This small lidar-based distance sensor reports the distance of objects up to about 50 cm (20") away with a pulsed signal similar to a hobby servo control ...

$28.50 AUD, inc GST

$25.91 AUD, exc GST

Available with a lead time
Expect dispatch between May 09 and May 12

Quantity Discounts:

10+ $25.13 (exc GST)
25+ $24.62 (exc GST)

This compact sensor makes it possible to measure the distance of objects up to about 50 cm (20") 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 3 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.


#4050: Digital output, 5cm	5 cm	< 5 mm	145 Hz	0000	irs16a
#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
#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)
#4064: Pulse width output, 50cm max	~50 cm	1 cm	3 mm	50 Hz	1110	irs16a
#4071: Pulse width output, 130cm max	~130 cm	4 cm	1 mm	100 Hz	0101	irs17a
#4079: Pulse width output, 300cm max	~300 cm	4 cm	2 mm	30 Hz	1101	irs17a

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 Pololu's 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:

Firmware version history

The Pololu Digital Distance Sensors (irs16a and irs17a) use a small integrated microcontroller to operate the distance sensor, drive the OUT pin, and control the on-board LED. There have been several different versions of the firmware for this microcontroller:

Version 2: This is the initial-release version of the irs16a firmware.
Version 3: This is the initial-release version of the irs17a firmware; it is not used on the irs16a boards.
Version 4: This update for the irs16a boards fixes a bug in the version 2 firmware that could cause some units to erroneously have a 25 cm offset in their readings (i.e. to incorrectly measure distances as approximately 25 cm farther than reality). Only a small percentage of boards with version 2 firmware were susceptible, and the problem only occurred when those susceptible units were operating in modes with a maximum sensing range of 20 cm or more. All irs16a units shipped from Pololu on or after January 30th, 2024 have firmware version 4. This firmware is not used on the irs17a boards.

If you have an affected irs16a unit with firmware version 2 and you would like a replacement, please contact us.

Determining the firmware version

When you apply power to the board or make it reset by any other means, the microcontroller transmits a signal with the firmware version on the via marked in the picture below.

The via that outputs firmware version information at startup on a Pololu Digital Distance Sensor.

To see the signal, you can probe the via with an oscilloscope. Configure it to trigger on a rising edge with a threshold around 1 V to 2 V and to capture data for at least 1 ms after the trigger. Then apply power to the distance sensor.

Each bit in the signal is transmitted as a high pulse. A 1 µs pulse indicates a 0, while a 3 µs pulse indicates a 1. The first two bits are 1 and 0, and they are followed by an 8-bit firmware version number, most significant bit first. The signal from a board running firmware version 4 looks like this:

Version signal from a Pololu Digital Distance Sensor running firmware version 4 (100 in binary).

People often buy this product together with:

Pololu Digital Distance Sensor 5cm

Pololu Digital Distance Sensor 10cm

Pololu Digital Distance Sensor 15cm

Dimensions

Size:	0.85" × 0.35" × 0.122"
Weight:	0.4 g

General specifications

Resolution:	3 mm
Maximum range:	50 cm¹
Sampling rate:	50 Hz²
Minimum operating voltage:	3.0 V
Maximum operating voltage:	5.5 V
Supply current:	30 mA³
Output type:	digital pulse width

Identifying markings

PCB dev codes:	irs16a
Other PCB markings:	0J13085

Notes:

1: This maximum is only achievable for high-reflectance objects in good ambient conditions; lower-reflectivity targets or poor ambient conditions will reduce the maximum range.
2: Minimum.
3: Typical average current draw when enabled; disabling via the EN pin reduces it to around 0.4 mA.

File downloads

Dimension diagram of the Pololu Digital Distance Sensors (irs16a) (191k pdf)
3D model of the Pololu Digital Distance Sensors (irs16a) (4MB step)
Drill guide for the Pololu Digital Distance Sensors (irs16a) (22k dxf)

This DXF drawing shows the locations of all of the board’s holes.

Recommended links

micro:bit MakeCode serial example for the Pololu Distance Sensor with Pulse Width Output, 50cm Max

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