Pololu Digital Distance Sensor 5cm

Overview

This compact sensor is a great way to quickly detect the presence of nearby objects. 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.

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.

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 update rate: 145 Hz (6.9 ms period)
Field of view (FOV): 15° typical; can vary with object reflectance and ambient conditions
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 (192k pdf) for more information
Weight: 0.014 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 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. The table in the section below shows the jumper settings for the different versions.

Specification

Dimensions

• Size: 0.85″ × 0.35″ × 0.122″
• Weight: 0.4 g

General specifications

• Maximum range:  5 cm
• Sampling rate:   145 Hz1
• Minimum operating voltage:  3.0 V
• Maximum operating voltage:  5.5 V
• Supply current:  30 mA2
• Output type:   digital3

Identifying markings

• PCB dev codes:  irs16a
• Other PCB markings:  0J13085

Notes:

• Minimum.
• Typical average current draw when enabled; disabling via the EN pin reduces it to around 0.4 mA.
• Low when detecting an object, high otherwise.