New Improved Multizone Time-of-Flight Sensor from ST
The STMicroelectronics VL53L8CX offers improved ranging performance and lower power consumption
STMicroelectronics has introduced the VL53L8CX, the latest-generation 8×8 multizone time-of-flight (ToF) ranging sensor. The VL53L8CX offers a range of improvements including greater ambient-light immunity, lower power consumption, and enhanced optics.
The VL53L8CX direct-ToF sensor combines a 940nm vertical cavity surface emitting laser (VCSEL), a multizone SPAD (single-photon avalanche diode) detector array, and an optical system comprising filters and diffractive optical elements (DOE) in an all-in-one module that outperforms conventional micro lenses typically used with similar alternative sensors. The sensor projects a wide square field of view of 45° x 45° (65° diagonal) and receives reflected light to calculate the distance of objects up to 400cm away, across 64 independent zones, and up to 30 captures per second.
The sensor boosts ranging performance with a new-generation VCSEL and advanced silicon-based meta-optics. Compared with the current VL53L5CX, the enhancements increase immunity to interference from ambient light, extending the sensor’s maximum range in daylight from 170cm to 285cm and reducing power consumption from 4.5mW to 1.6mW in low-power mode.
By increasing performance over the VL53L5CX, the new VL53L8CX now further extends the advantages of these sensors over alternatives with conventional optics, which have fewer native zones and lose sensitivity in the outer areas. Thanks to its true 8×8 multizone sensing, the VL53L8CX ensures uniform sensitivity and accurate ranging throughout the field of view, with superior range in ambient light.
When used for system activation and human presence detection, the VL53L8CX’s greater ambient-light immunity enables equipment to respond more consistently and quickly. As part of ST’s STGesture™ platform that also includes the STSW-IMG035 turnkey gesture-recognition software and Gesture EVK development tool, the new sensor delivers the precision needed for repeatable gesture-based interaction. In addition to motion gesture recognition, hand posture recognition is also possible leveraging the latest AI models available in the STM32ai-modelzoo on GitHub.
Moreover, the VL53L8CX provides increased accuracy for monitoring the contents of bins, containers, silos, and tanks, including liquid-level monitoring, in industrial bulk storage and warehousing. The superior accuracy can also enhance the performance of drinks machines such as coffee makers and beverage dispensers.
Mobile robots including autonomous vacuum cleaners can leverage the VL53L8CX to improve guidance capabilities like floor sensing, small object detection, collision avoidance, and cliff detection. Also, the synchronization pin enables projectors and cameras to benefit from coordinated autofocus. There is also a motion indicator, an auto-stop feature that allows real-time actions, and the sensor is immune to cover-glass crosstalk beyond 60cm. Now supporting SPI connectivity, in addition to the 1MHz I2C interface, the new sensor handles host data transfers at up to 3MHz.
Features of the VL53L8CX Time-of-Flight Sensor include:
- New generation, multizone Time-of-Flight (ToF) sensor with low-power and enhanced distance ranging performance
- Multizone distance measurement capability with either 4x4 or 8x8 separate zones
- Autonomous low-power mode with interrupt programmable threshold to wake up the host
- Ranging up to 400 cm, with enhanced performance under ambient light
- Multitarget detection and distance measurement in each zone
- Histogram processing and algorithmic compensation to minimize or remove the impact of cover glass crosstalk
- Motion indicator for each zone to show if targets have moved and how they have moved
- Frame rate capability of 60 Hz
- Fully integrated miniature module with wide field of view (FoV)
- New generation, high-power emitter: 940 nm invisible light VCSEL (vertical-cavity surface-emitting laser) and integrated analog driver
- 65° diagonal square FoV using DOEs (diffractive optical elements) on both transmitter and receiver
- Receiving array of SPADS (single photon avalanche diodes)
- Low-power microcontroller running firmware
- Size: 6.4 x 3.0 x 1.75 mm
- Easy integration
- Single reflowable component
- Requires 1.8 V core supply and 3.3 V AVDD supply
- Optional 1.2 V or 1.8 V IOVDD interface voltage levels
- Compatible with wide range of cover glass materials
- Can be hidden behind a dark cover glass
- I²C (up to 1 MHz) or SPI (up to 3 MHz) interface
More information on the VL53L8CX Time-of-Flight 8x8 Multizone Ranging Sensor is available on the ST website at STMicroelectronics VL53L8CX product page.
The STMicroelectronics website address is www.st.com
[Reprinted with kind permission from STMicroelectronics - Release Date, 14th December, 2023]