STMicroelectronics Next generation multi-zone time-of-flight sensors improve ranging performance and energy efficiency

     STMicroelectronics' latest generation 8x8 Multi-zone time-of-flight (ToF) ranging sensor, the VL53L8CX, implements a number of improvements, including greater resistance to ambient light interference, lower power consumption and enhanced optical performance. St's direct ToF sensors integrate a 940nm vertical cavity surface-emitting laser (VCSEL) and a multi-region SPAD(single-photon avalanche diode) detector array in a single module, along with an optical system consisting of filters and diffracted optical elements (DOE).

     Among them, the performance of the optical system is better than that of conventional microlenses commonly used in similar substitutable sensors. The new sensor has a field of view Angle of 45°x45°(65° diagonal), calculates the distance of the object to the sensor by receiving reflected light, and measures up to 400 cm in 64 separate areas, ranging up to 30 times per second.

     The new VL53L8CX improves ranging performance by using a new generation of VCSEL light sources and advanced silicon-based optics. Compared with the existing ranging sensor VL53L5CX, the new sensor improves the resistance to ambient light interference, extending the daylight ranging performance from 170 cm to 285 cm in low-power mode, while reducing the power consumption from 4.5 milliwatts to 1.6 milliwatts.

     ST released its first multi-zone time-of-flight sensor, the VL53L5CX, in 2021. By improving ranging performance, the new VL53L8CX further widens the advantage gap between ST sensors and alternatives using traditional optical components, which have fewer inherent ranging areas and less sensitivity in the peripheral measurement area. Thanks to true 8x8 multi-zone ranging, the VL53L8CX ensures consistent sensitivity across the entire field of view, high ranging accuracy, and longer range in ambient light conditions.

     When the VL53L8CX is used for system activation and human presence detection, better resistance to ambient light interference makes the device more responsive and stable in performance. The VL53L8CX is also a hardware component of ST's STGesture™ platform, along with the STSW-IMG035 gesture recognition package and gesture EVK development tool. The new sensor provides the ranging accuracy required for repeatable motion interactions. In addition to action recognition, gesture recognition can also be achieved using the latest AI model in STM32ai modelzoo on GitHub.

     In addition, in industrial bulk storage and warehousing, the VL53L8CX can improve the accuracy of capacity and level monitoring of tanks, containers, silos and tanks. Excellent ranging accuracy can also improve the performance of beverage machines such as coffee machines and beverage dispensers.

     The VL53L8CX can be used by mobile robots, including autonomous vacuum cleaners, to improve tracking and navigation capabilities, such as floor sensing, small object detection, collision avoidance and suspended drop detection. In addition, synchronization pins speed up the autofocus of the projector and camera. There is also a motion indicator on the module, which is an automatic stop function that allows real-time action. The sensor is not affected by cover crosstalk at distances beyond 60 cm. Now, in addition to the 1MHz I2C interface, the new sensor also supports the SPI interface for up to 3MHz data transfer with the main controller.

     Designers can quickly evaluate VL53L8CX with a supporting ecosystem to accelerate project development. The development ecosystem includes the X-NUCLEO-53L8A1 expansion board and the SATEL-VL53L8 adapter board. St also offers the P-NUCLEO-53L8A1 development kit, which includes the STM32F401 NUCLEO microcontroller board and the X-NUCLEO- 53L8A1 expansion board, which can be powered on at any time to begin development.