Pololu Digital Distance Sensor v2, 5cm

Overview

Pololu Digital Distance Sensor v2, 5cm.

This compact sensor provides a simple way to detect the presence of objects up to 5 cm (2″) away. As long as the sensor is enabled, it takes continuous distance measurements and uses a single digital output to indicate if it detects an object within its detection range. The output is driven low when the sensor detects an object; otherwise, the output is high.

A camera with no IR filter shows the infrared light emitted by a Pololu Digital Distance Sensor (this light is eye-safe and not visible to the naked eye).

Please note that this sensor will only tell you if there is an object within the detection range along its line of sight, not how far away it is. As shown in the diagram above, there is hysteresis at the maximum range threshold to help ensure a clean transition as objects cross the threshold. The sensor can detect objects to within less than 1 mm of the sensor face.

This sensor has 0.1″-pitch through holes that are compatible with 0.1″ headers. A functionally identical version is also available with a side-entry connector that works with our 3-pin JST SH-style cables.

Unlike simpler optical sensors that use the intensity of reflected light to detect objects, this sensor 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. This allows the sensor performance to be largely independent of object reflectivity and ambient lighting conditions (though the range can be reduced for extremely low-reflectance objects).

Some example applications include:

• break-beam sensor or photogate alternative
• non-contact bumper or obstacle detector for a robot
• non-contact interface element for activating a device or process
• a counter or timer of objects as they pass by

Specifications

• Operating voltage: 3.0 V to 5.5 V
• Current consumption: 30 mA (typical) when enabled, 0.4 mA when disabled
• Maximum range: 5 cm (2″)
• Minimum range: < 1 mm
• Minimum update rate: 142 Hz (7 ms period)
• 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 signal (low when detecting an object, high otherwise)
• Dimensions: 0.85″ × 0.35″ × 0.122″ (21.6 × 8.9 × 3.1 mm); see the dimension diagram (277k pdf) for more information
• Weight: 0.015 oz (0.4 g)

Using the sensor

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 OUT pin drives low (0 V) when an object is being detected and it drives high (to the VIN level) when an object is not being detected. It is weakly pulled high when the sensor is disabled or waiting for its first reading to complete after power-up. A red LED on the back side of the board also lights whenever an object is detected.

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.

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. This sensor can be converted into any other v2 short-range version as listed in the following table. (For more information about how the different output types work, see the product pages for representative versions.)

V2 short-range version jumper settings
Item #		Description	Maximum range(1)	Hysteresis	Resolution	Minimum update rate	Jumper settings (4321)
no connector	side-entry connector
#5550	#5460	Digital output, 5cm	5 cm	35 mm	-	142 Hz	0000
		Digital output, 5cm (high sensitivity)	5 cm	21 mm	-	66 Hz	0001
#5552	#5462	Digital output, 10cm	10 cm	35 mm	-	142 Hz	0010
		Digital output, 10cm (high sensitivity)	10 cm	21 mm	-	66 Hz	0011
#5554	#5464	Digital output, 15cm	15 cm	35 mm	-	142 Hz	0100
		Digital output, 15cm (high sensitivity)	15 cm	21 mm	-	66 Hz	0101
		Digital output, 20cm	20 cm	35 mm	-	142 Hz	0110
		Digital output, 20cm (high sensitivity)	20 cm	21 mm	-	66 Hz	0111
		Digital output, 30cm	30 cm	35 mm	-	142 Hz	1000
		Digital output, 30cm (high sensitivity)	30 cm	21 mm	-	66 Hz	1001
		Digital output, any detect	~100 cm	-	-	142 Hz	1010
		Digital output, any detect (high sensitivity)	~100 cm	-	-	66 Hz	1011
#5562	#5472	Pulse width output, 50cm max	~50 cm	-	1 mm (= 1.33 µs)	142 Hz	1100
		Pulse width output, 50cm max (high sensitivity)	~50 cm	-	1 mm (= 1.33 µs)	66 Hz	1101
		Pulse width output, 100cm max	~100 cm	-	1 mm (= 0.5 µs)	142 Hz	1110
		Pulse width output, 100cm max (high sensitivity)	~100 cm	-	1 mm (= 0.5 µs)	66 Hz	1111
Note 1: 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 versions of Pololu Digital Distance Sensors with different ranges, operating modes, and connector options:

High/low digital output (indicates detection within specified range; does not provide distance measurement)
Sensor type	Item #		Maximum range(1)	Minimum range	Hysteresis	Minimum update rate	Price
	no connector	side-entry connector
original short‑range (irs16a)	#4050		5 cm	< 5 mm	16 mm	145 Hz	$19.95
	#4052		10 cm		20 mm	115 Hz
	#4054		15 cm		24 mm	95 Hz
v2 short-range	#5550	#5460	5 cm	< 1 mm	35 mm	142 Hz	$19.95
	#5552	#5462	10 cm
	#5554	#5464	15 cm
long-range	#4066	#5480	25 cm	< 1 mm	50 mm	100 Hz	$24.95
	#4067	#5481	50 cm			100 Hz
	#4069	#5483	100 cm			100 Hz
	#4077	#5491	200 cm			30 Hz
Pulse width output (provides distance measurement encoded as the width of a digital pulse)
Sensor type	Item #		Maximum range(1)	Minimum range(2)	Resolution	Minimum update rate	Price
	no connector	side-entry connector
original short-range	#4064		~50 cm	1 cm	3 mm (= 4 µs)	50 Hz	$19.95
v2 short-range	#5562	#5472	~50 cm	< 0.1 cm	1 mm (= 1.33 µs)	142 Hz	$19.95
long-range	#4071	#5485	~130 cm	4 cm	1 mm (= 0.5 µs)	100 Hz	$24.95
	#4079	#5493	~300 cm	4 cm	2 mm (= 0.5 µs)	30 Hz
Note 1: Effective range depends on object reflectivity and ambient lighting conditions. Note 2: Objects closer than the minimum distance can still be detected, but the measured distance might be inaccurate. The minimum detection distance is < 5 mm for the original (irs16a) short-range sensors and < 1 mm for everything else.

The Pololu Digital Distance Sensor family includes several different sensor types. The jumper options are different for the different sensor types, so it is important to be able to identify which type you have if you want to change the jumper settings. The following diagram shows some key visual differences among the different sensor types:

Comparison of the different Pololu Digital Distance Sensor versions.

Within each sensor type, there are digital output versions that just report if an object is within their detection range and pulse width output versions that report the measured distance by encoding it as the width of a repeating digital pulse, similar to hobby servo control signals. The graphs below show some examples of the different possible output signals from the different Pololu Digital Distance Sensor versions.

Comparison to Sharp/Socle Digital Distance Sensors

These Pololu Digital Distance Sensors have the same general form factor and pinout as our carrier boards for the Sharp/Socle GP2Y0D8x digital distance sensors (the versions with through-holes have the same length and width while the versions with JST SH-style connectors are 0.05″ longer). They are available in the same 5 cm, 10 cm, and 15 cm ranges as the Sharp/Socle sensors, 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 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: