Hi,
I have recently purchased a whole bunch of the 4050 Pololu Digital Distance Sensors as they seem to be the holy grail of object sensor that I have been looking for! I built some interactive games that detect balls being thrown through holes in a backboard and always had trouble finding a reliable sensor to detect the object.
Quick History:
I started with a 2-part “beam-break” sensor but the wiring was messy with the emitter on one side and the detector on the other.
Then I switched to a reflective IR sensor (same basic tech, but the emitter and detector are next to each other) but the cheap non-modulated sensors I was using were completely useless outdoors (Sunlight) or in certain indoor lighting situations (Fluorescents, etc).
Then I found the sharp sensors / carriers from Pololu which seemed great at first (Fixed the ambient IR problem as they were modulated) but I would get random “detections” when I had multiple sensors going at the same time - first they seemed “electrical” I was advised to add a parallel capacitor to the power lines for each sensor - it helped but I was still getting false triggers. (I think it was having many sensors in an enclosed space which was causing random triggers - I was never fully sure.)
But alas, the Pololu Digital Distance Sensor (using the 5cm version, #4050) seems to be working exactly as I need it to! Eureka and thank you!
My question is, how do these work?
What I mean is, how are these “LiDAR-based” sensors different than the standard “IR-based” sensors (such as the Sharp sensors). It is my understanding that these also emit some king of modulated IR light and detect it just the same, but they seem to work just fine exposed under direct Sunlight (I tested) and do not seem to be suffering from (that I think were) random IR reflections from inside my enclosure.
My understanding of LiDAR (which isn’t much) is that there is a rotating beam of laser light that is then picked up by a camera or other sensor and the distance of each point of light is measured (time of flight??) to determine how far away objects are. But clearly these sensors are much simpler than the LiDAR we used to see spinning on the top early-prototype self-driving cars, so I am also wondering what makes these “LiDar-based?”
Your understanding of lidar (light detection and ranging) is basically correct except for that the laser does not necessarily need to be rotating like the devices you have seen on self-driving cars (although that is probably the most well known example of lidar technology; rotation allows it to scan around one or more axes instead of looking in just a single direction). It is the fact that these sensors operate by measuring the time for reflected light from the laser to return to the receiver that make our Pololu Digital Distance Sensors lidar based.
This Wikipedia page might be a good place to learn more about lidar in general. If you want to learn more about the sensors on our digital distance sensors, then you could look at the other ST time-of-flight sensor carriers listed in our Lidar/Time-of-Flight Range Finders category page, along with their datasheets and other documentation, since those are less abstracted breakout boards for the same types of sensors as we use on our digital distance sensors. You could also look at ST’s website.
Hello Pololu, I’m wondering which exact sensor is used in the digital distance sensors. We’d like to use them for for FIRST Tech Challenge, but they have some history of dis-allowing TOF sensors (though there is a legal one). I think we’ll need to list the exact ST part and safety standard to be allowed to use them.
Thanks!
There are two board and sensor versions at this time. You can tell them apart using the silkscreen text in the corner of the board. Boards that say irs16a use the VL6180X, while ones with a marked irs17a use the VL53L1X. We have separate carrier boards for those sensors as well, and you can find a datasheet for the sensor under the “Resources” tab of their respective product page:
Lidar sensors are one type of ultrasonic sensor.Cause both of these sensor works through emitting ultrasounds. But lidar is a upgraded version of the ultrasonic one.
We are using the digital distance sensors (5cm, irs16a - 0J13085, 2020) - which function well, and wish to know what the lidar classification is regarding eye safety?
We are looking to get a better understanding of the digital distance sensors such as the #4054 discussed here. To understand the full system for EMI and data stability. The VL ToF outputs a i2c signal and i was wondering how this is processed to output the binary signal? It seems there is an extra IC placed to do this?
Thank you, Patrick.
We intend to have several of these sensors wired into projects here at the University, so “eye-safe” needed to be confirmed for safety reasons.
The sensor functions well through glass, which will provide touchless switching for our demo displays. I imagine that the laser wavelength is near far-red ~ 850nm.
