Pololu Distance Sensor with Pulse Width Output, 300cm Max
This small lidar-based distance sensor reports the distance of objects up to about300cm (120″)away 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. The sensor works over an input voltage range of 3.0V to 5.5V, and the 0.1″ pin spacing makes it easy to use with standard solderless breadboards and 0.1″ perfboards.
This compact sensor makes it possible to measure the distance of objects up to about 300cm (120″) away using a simple digital pulse width interface (similar to ahobby 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 2mm 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 distanced(in mm) and pulse widtht(in µs) is as follows:
The timing uncertainty is approximately ±5%. As objects approach the sensor, the output pulse width will approach 1.0ms, while an object detected at 300cm will produce a 1.75ms pulse width. The sensor uses a pulse width of 2.0ms to indicate no detection. The pulse periodTranges from around 30ms to 33ms, 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 wall out to around 300cm away, a white sheet of paper out to around 170cm, and a hand out to around 100cm. The following graph shows the measured distances of three units versus their actual distances from a variety of targets at several different ranges:
Please note that while this sensor can detect objects to within about 1mm of the sensor face, the effective minimum distance it can measure is around 4cm, so objects closer than 4cm might result in an inaccurate measurement.
Specifications
Dimensions
| Size: | 0.85″ × 0.35″ × 0.136″ |
|---|---|
| Weight: | 0.4 g |
General specifications
| Resolution: | 2 mm |
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| Maximum range: | 300 cm1 |
| Sampling rate: | 30 Hz2 |
| Minimum operating voltage: | 3.0 V |
| Maximum operating voltage: | 5.5 V |
| Supply current: | 30 mA3 |
| Output type: | digital pulse width |