Tiny industrial time-of-flight distance sensor works up to 1m

STMicroelectronics has created a time-of-flight distance sensor for industrial use.

VL53L4ED works over -40 to +105°C and in high ambient light, and provides “provides distance measurement to objects up to 1,150mm away over the full temperature range,” according to the company. “Special settings allow accurate distance measurement up to 800mm under strong ambient light [5klux].”

On-board the 4.4 x 2.4 x 1mm LGA package are a 940nm emitter “that is totally safe for eyes”, said ST, and a spad (single-photon avalanche-diode) detector. The laser emerges perpendicular to the 1mm thickness.

Ranging can work as far as 1.3m with a white target and the right lighting conditions, reducing to 400mm with a grey target and less ideal lighting. Mimimum range is 1mm, but presence can be detected at 0mm.

Measuring capability tails off above 60°C and below 10°C (in the dark), and outside its ±9° field of view.

Accuracy depends on ambient light and range, and is generally better than ±7mm close up and ±5% further away – the data sheet has plenty of information. “Up to two calibrations are needed to ensure the best sensor performance,” said ST. “Offset is needed in all applications. If a cover glass is used, cross-talk calibration is also needed.”

Recommended operation is from 2.7 to 3.4V (2.8V nominal), with the IO supply allowed as low as 1.7V for the I²C interface.

Max averaged consumption when ranging is 24mA, which can have peaks up to 40mA within it. Stand-by is at under 10μA.

To go with the company’s own microcontroller range, there is X-CUBE-TOF1 expansion software for the STM32Cube development ecosystem, and the STSW-IMG034 driver “that lets an interrupt command turn the VL53L4ED into a proximity detector for user detection and touchless control”, plus STSW-IMG039 software for liquid-level monitoring.

Find the VL53L4ED product page here, from where the data sheet is linked.