Tag Archives: time of flight

Broadcom AFBR-S50 ToF laser light sensor measures up to 10 meters

The AFBR – S50 is a multipixel distance and motion measurement sensor. It has an integrated 850nm vertical cavity surface emitting laser (VCSEL) which uses a single voltage supply of 5V. It’s measurement rates are quick and as fast as 3 kHz, which is a distinguishing feature. However, this is not the reason why the AFBR – S50 stands out. It is different because unlike other Time of Flight (ToF) ranging sensors, the AFBR – S50 can measure up to 10 meters whereas similar sensors don’t get close to that.

The AFBR-S50

Furthermore, the sensor works on the principle of Optical Time of FlightTime-of-Flight principle (ToF) is a method for measuring the distance between a sensor and an object, based on the time difference between the emission of a signal and its return to the sensor, after being reflected by an object. If you have used the popular HC-SR05 Ultrasonic sensor, then you have seen this principle in action. The AFBR – S50 can be used both inside and outside to cover wide ranges of ambient light. It supports almost 3000 frames every second with an accuracy of less than one percent on diverse types of surfaces.

ToF Principle

The multi-pixel sensor works with up to 16 illuminated pixels out of 32 and with its best-in-class ambient light suppression of up to 200kLx, to ensure smooth usage outside. It uses SPI Interface to communicate with a host device. AFBR – S50 not only works outside but it is also equally effective on colored, white, black and metallic reflection objects.

Broadcom has released two different versions of the sensor:

  • AFBR-S50MV680B
    • 680nm laser light source.
    • One illuminated pixel
    • FOV (Field Of View) 1.55° x 1.55°
    • Single voltage – 5V supply
  • AFBR-S50MV85G
    • 850nm laser light source
    • 9-16 illuminated pixels
    • FOV 6.2° x 6.2°
    • Single voltage – 5V supply

Below are the General Specifications for the Multipixel sensor:

  • Integrated 850nm laser light source.
  • Between 9-16 illuminated pixels.
  • FOV 6.2°x 6.2° (1.55 x 1.55°/pixel).
  • High-speed measurement rates of up to 3 kHz.
  • Variable distance range up to 10m.
  • Operation up to 200k Lux ambient light.
  • Works well on all surface conditions.
  • SPI digital interface (up to 20 MHz).
  • Single voltage supply 5V.
  • Integrated clock source.
  • Laser Class 1.
  • Accuracy < 1 percent.
  • Drop-in compatible with the AFBR-S50 sensor platform

Applications for the ToF sensor can be found in areas of industrial sensing, gesture sensing, distance measurement, robotics, drones, automation, and control. The AFBR-S50 is available, but the price is currently undisclosed. You can contact Broadcom sales for more information. More details can be found on the product page, and the AFBR-S50 datasheet can be found here.

Chirp Microsystem Made The Smallest And Most Accurate Ultrasonic Time-of-Flight Sensors

Recently Californian startup Chirp Microsystems officially announced two discrete ultrasonic Time-of-Flight (ToF) sensors, the CH-101 and CH-201, with maximum sensing ranges of 1m and 5m, respectively. Both chips have a 3.5×3.5mm package and they are powered by same ASIC or application-specific integrated circuit for signal processing. To achieve different sensing ranges, the Piezoelectric Micro-machined Ultrasonic Transducers (PMUT), the MEMS parts of the sensors are tuned and built differently.

Chirp Microsystem designed smallest and most accurate ultrasonic Time-of-Flight sensors

Chirp Microsystems was founded in 2013 and the CH-101 is their 2nd generation design while the CH-201 is an upgraded third generation design. Their 4th generation design of chips is under development and prototypes are being tested recently. Chirp Microsystems declares that with each design so far, they’ve improved their transmitter and receiver performance by 4 times. David Horsley, Chirp Microsystems’ CTO, told,

In fact, we have been sampling the CH101 for two years now and we realized we had never made a product announcement for it.

According to Chirp Microsystems, the chips are the first commercially available MEMS-based ultrasonic ToF sensors and can beat all other ToF solutions on the small size and low power consumption. The “Sonars on a chip” draw 100 times less power and are a thousand times smaller than the conventional ultrasonic rangefinders used in today’s industrial automotive applications. Unlike infrared based ToF sensors, these new MEMS sensors do not rely on optical path clearance. So, it’s now easier for engineers to design bezel-free smartphones with precise gesture recognition.

The CH-101 and CH-201 include an interrupt pin and a GIO pin. That pin is used in hardware trigger mode to connect several transducers on the same I2C bus so they can operate in a synchronous fashion. For Virtual Reality applications, data from multiple chips are mixed to detect the position of user’s hand in 3D space.

Previously the California based startup also made monolithic linear arrays that had ten transducers in a row. Using that design, one can perform beamforming and identify both range and position of an object. Though they stayed away from commercializing it. “We didn’t want to bite too much at a time” – said the CTO of the startup. Rather they decided to focus on solving various manufacturing and packaging issues first. Horsley, the CTO of the Chirp Microsystems, also added,

We are pioneers in this area, and we are not close to the optimum yet, we still have a lot of design space to improve the specs.

8×8 pixel Time-of-Flight sensor is only 2.65×2.7mm

Swiss company Espros has completed its cwTOF imager family with the epc611, its smallest Time-of-Flight sensor to date, measuring only 2.65×2.7mm and delivering a 8×8 pixel field. by Julien Happich @ eenewseurope.com:

Sampling now and in volume production at TSMC, the chip can either be used as an 8×8 pixel imager for simple gesture recognition, door protection, or presence detection near machines, or as a fast range finder for simultaneous localization and mapping (SLAM) applications with rotating sensors.

8×8 pixel Time-of-Flight sensor is only 2.65×2.7mm – [Link]

MappyDot – Micro Smart LiDAR Sensor

Blecky @ hackaday.io:

MappyDot is a smart ranging sensor which provides system designers with the ability to measure accurate distances on drones and robotic platforms for collision avoidance, area mapping, distance measurement, gesture recognition and motion sensing. The MappyDot uses the VL53L0X laser time-of-flight ranging sensor from STMicroelectronics, which is a tried and tested 940nm Class 1 laser sensor in use in millions of devices worldwide.

MappyDot – Micro Smart LiDAR Sensor – [Link]

LED-based time-of-flight IC for object detection and distance measurement

Intersil-ISL29501-application-diagram

by Lee Goldberg @ edn.com:

Although Intersil’s ISL29501 time-of-flight (ToF) signal processing IC doesn’t have anything to do with the lighting applications I normally cover, I felt compelled to bring it to your attention because it’s one of the most innovative LED applications I’ve seen this year. The device requires little more than an external emitter (LED or laser) and a photodiode to implement a complete object detection and distance measurement solution that provides precision long-range accuracy up to 2m in both dark and bright ambient light conditions.

LED-based time-of-flight IC for object detection and distance measurement – [Link]