Pololu Distance Sensor v2 with Pulse Width Output and Side-Entry Connector - 50cm Range

This small lidar-based distance sensor from Pololu reports the distance of objects up to about 50 cm (20″) away (Pololu 5472) 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. It works over an input voltage range of 3.0 V to 5.5 V and features a side-entry 3-pin JST SH-style connector that is compatible with our 3-pin JST SH-style cables. 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.

The relationship between measured distance d (in mm) and pulse width t (in µs) is as follows: d = (3 mm / 4 µs) * (t – 1000µs) t = 1000 µs + (4 µs / 3 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 50 cm will produce a 1.667 ms pulse width. The sensor uses a pulse width of 2.0 ms to indicate no detection, and the pulse period T ranges from around 6 ms to 7 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 around 50 cm away, and it could reliably detect a hand out to around 30 cm away. The following graph shows the measured distances of five units versus their actual distances from a white paper target at several different ranges:

This sensor features a side-entry 3-pin male JST SH-style connector that works with our 3-pin JST SH-style cables. 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 neighbouring surface-mount pad on the back side labelled “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, 50cm Max and displays the measured distance in millimeters. // Example Arduino program for reading the Pololu Distance Sensor with Pulse Width Output, 50cm Max

// Change this to match the Arduino pin connected to the sensor's OUT pin. const uint8t sensorPin = 2;

void setup() {

Serial.begin(115200); }

void loop() {

int16t t = pulseIn(sensorPin, HIGH);

if (t == 0)

{

// pulseIn() did not detect the start of a pulse within 1 second.

Serial.println("timeout");

}

else if (t > 1850)

{

// No detection.

Serial.println(-1);

}

else

{

// Valid pulse width reading. Convert pulse width in microseconds to distance in millimeters.

int16t d = (t - 1000) * 3 / 4;

// Limit minimum distance to 0.

if (d < 0) { d = 0; }

Serial.print(d);

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, 50cm 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 for v2 short-range versions

This 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. Specifications

Operating voltage 3.0 V to 5.5 V

Supply current 30 mA (typical) when enabled, 0.4 mA when disabled2

Maximum range 50 cm (20″)

Minimum range < 1 mm

Resolution 1 mm

Update rate 142 Hz (7 ms period)1

Field of view (FOV) 10° typical (can vary with object reflectance and ambient conditions)

Emitter Eye-safe 940 nm invisible Class 1 VCSEL (vertical cavity surface-emitting laser)

Output type Digital pulse width

Connector Side-entry, 3-pin JST SH-type

PCB dev codes irs17b

Other PCB markings 0J15469, 0J15601, or 0J15851

Size 0.9″ × 0.35″ × 0.2″ (22.9 × 8.9 × 5.2 mm)

Weight 0.5 g (0.02 oz)

* Minimum.

* Typical average current draw when enabled; disabling via the EN pin reduces it to around 0.4 mA.

Resources

* micro:bit MakeCode serial example

* Dimensions

* 3D Model (STEP)

* Drill Guide

Package Contents

* 1x Pololu Distance Sensor v2 with Pulse Width Output and Side-Entry Connector - 50cm Range