Pololu Distance Sensor with Pulse Width Output, 50cm Max

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.

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. The pulse period T ranges from around 9 ms to 20 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:Please note that while this sensor can detect objects to within about 5 mm of the sensor face, the effective minimum distance it can measure is around 1 cm, so objects closer than 1 cm might result in an inaccurate measurement.

Specifications

• Operating voltage: 3.0 V to 5.5 V
• Current consumption: 30 mA (typical) when enabled, 0.4 mA when disabled
• Maximum range: approximately 50 cm (20″) (for high-reflectivity targets in good ambient conditions; lower-reflectivity targets or poor ambient conditions will reduce the maximum detection range)
• Minimum range: 1 cm (for accurate measurement); < 5 mm (for detection)
• Update rate: 50 Hz to 110 Hz (20 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″ × 0.122″ (21.6 × 8.9 × 3.1 mm);  (191k pdf) for more information
• Weight: 0.014 oz (0.4 g)