10 ms·

OpenSimpleLidar

605 points by lovelearning 9y ago

Dangeranger 9y ago
Thanks for this. When I first started working in LiDAR nearly ten years ago the cheapest hardware you could acquire was $25,000 and completely proprietary. It’s nice to see a simple hardware hack for playing with the technology. Maybe this will encourage some intrepid engineers to build the next wave of hobbyist point cloud collection devices. There are lots of fun applications like home surveying to 3D model generation.
- rburhum 9y ago
  Velodyne?
  - rtkwe 9y ago
    Personally, anywhere I can't see a price without contacting a sales rep from the company I hesitate to call hobbyist.
    - nix0n 9y ago
      I agree, definitely not for hobbyists. List price seems to be $8,000 if you're just buying one of their cheapest product. http://velodynelidar.com/docs/news/This%20Palm-Sized%20Laser%20Could%20Make%20Self-Driving%20Cars%20Way%20Cheaper%20_%20WIRED.pdf http://velodynelidar.com/docs/news/This%20Palm-Sized%20Laser...
    - drharby 9y ago
      Eh some motors i needed for building an r2 droid came from such a site. But yes on the whole i concur
  - michaelt 9y ago
    At the time Velodyne brought out their HDL-64E for ~$75,000 you could buy a SICK LMS-200 for about 10% of that. That's why loads of the DARPA Grand Challenge vehicles were plastered in SICK LIDARs [1] back when Velodyne only had one prototype, and it was on a truck they were putting in the competition themselves [2]. Course, Velodyne's product may be 10x the cost, but it has 64x the number of lasers, and good range and direct sunlight performance, so it's understandable that it took off. [1] https://www.alamy.com/stock-photo-sep-28-2005-fontana-ca-usa-autonomous-team-vehicles-before-the-start-64082198.html https://www.alamy.com/stock-photo-sep-28-2005-fontana-ca-usa... [2] https://www.popsci.com/scitech/article/2005-10/popscis-darpa-grand-challenge-preview-update-2 https://www.popsci.com/scitech/article/2005-10/popscis-darpa...
- beambot 9y ago
  10 years ago was 2008. You could buy a Hokuyo for under $3k back then. Now depth cameras were a different story. SwissRanger was $10-15k, but were usurped by the sub-$200 Kinect just a few years later.
jbob2000 9y ago
Oh man this is cool! Now we just need OpenSimpleLaserWindow and we can listen to conversations and track people's movements just like the CIA! I forget where I read about this, but essentially, as you speak, your sound waves vibrate nearby windows, and these vibrations can be picked up with a laser and translated back into sound.
- godelski 9y ago
  There's a few ways you can do this. The cheapest is to just get a laser and a photo diode. It's rough, but you can get sounds. An interferometer works better. It's harder to make and more expensive, but in the hobby range, at least to get decent quality. There's tons of videos and documents that you can find showing you how to make either. You can also do a lot of cool measurements with these setups
  - jbob2000 9y ago
    I had never heard of an interferometer, it actually sounds like something out of a movie haha. Thanks for sharing!
    - deleted 9y ago
      [deleted]
    - godelski 9y ago
      The design is extremely simple. The hard part is aligning things. That's actually the hard part about most optics. If you're really OCD you need to be even more. Here's a little animation of one: https://www.youtube.com/watch?v=UA1qG7Fjc2A https://www.youtube.com/watch?v=UA1qG7Fjc2A
- deleted 9y ago
  [deleted]
atomical 9y ago
Pretty cool. This could be a good primer for Uber devs.
- SlowRobotAhead 9y ago
  Last article that was talking about Uber I asked why LIDAR wouldn’t have lit up that lady up. The response was “LIDAR might have been disabled”... as if that was any sort of acceptable scenario.
  - deleted 9y ago
    [deleted]
  - rootusrootus 9y ago
    Running without LIDAR, at night especially? If that is true, I can imagine that's why they paid off the family so quickly.
  - callumjones 9y ago
    It could be related to the fact that LIDAR tech was supposedly stolen from Waymo. Source: http://money.cnn.com/2018/02/07/technology/waymo-v-uber-technology/index.html http://money.cnn.com/2018/02/07/technology/waymo-v-uber-tech...
  - icebraining 9y ago
    They have one (compared to Waymo's six): https://www.reuters.com/article/us-uber-selfdriving-sensors-insight/ubers-use-of-fewer-safety-sensors-prompts-questions-after-arizona-crash-idUSKBN1H337Q?il=0 https://www.reuters.com/article/us-uber-selfdriving-sensors-...
  - imh 9y ago
    "Because I was driving with my eyes closed" or "Because I wasn't looking" would be the human equivalent. Imagine if the driver used the same excuse, when asked why she didn't see the pedestrian and take over.
    - 9y ago
le-mark 9y ago
What kind of precision can you get with a device like this? The image on the github page looks very imprecise, like on the order of cm of error. If one were to scan a 3d model, could one get sub millimeter resoluton for example?
- rubenbe 9y ago
  According to the hackaday page [0], the precision is indeed in the order of centimeters: 5 cm at 2 m and 10 cm at 3 m. [0] https://hackaday.io/project/20628-open-simple-lidar https://hackaday.io/project/20628-open-simple-lidar
  - dbcurtis 9y ago
    The Neato sensor does anlittle better, about 2cm at 5m
4ff618 9y ago
I really want to know the math behind the triangulation process
- danielvf 9y ago
  You know the angle of light entering the lens. The tangent of that angle gives you the ratio of (the distance between the lens and the laser) and (distance between the laser and the target). Which lets you work out the distance between the laser and target. Trigonometry rocks!
- 11235813213455 9y ago
  generalized Pythagorean theorem
donquichotte 9y ago
I still don't quite understand how this works. Main components are: - Laser - Lens - TSL1401 line image sensor I was always under the impression that LIDAR includes a time-of-flight measurement, which does not appear to be the case here - the TSL1401 sensor has integration times and pixel transfer times in the range of dozens of microseconds, a timespan in which light travels dozens of kilometers.
- fisherjeff 9y ago
  Based on the diagram, I believe they're estimating distance based on parallax rather than time of flight
  - donquichotte 9y ago
    I agree. The wikipedia article on LIDAR says "Lidar [...] combine[s] laser-focused imaging with the ability to calculate distances by measuring the time for a signal to return using appropriate sensors and data acquisition electronics." So this is not LIDAR. Still impressive though, I love the simplicity!
    - rtkwe 9y ago
      That's probably an overly specific definition. Their source for the lidar definition is a NOAA webpage [0] with a broader definition that doesn't include specifics about implementation: > LIDAR, which stands for Light Detection and Ranging, is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances) to the Earth. Most lidar does use timing but I'd argue that's a type of implementation instead of a necessary part of the broader category of lidar devices. [0] https://www.webcitation.org/6H82i1Gfx?url=http://oceanservice.noaa.gov/facts/lidar.html https://www.webcitation.org/6H82i1Gfx?url=http://oceanservic...
    - adamweld 9y ago
      The LIDAR acronym doesn't specify the specific measurement technique, although Time Of Flight is by far the most common. There are other designs with interesting differences, for example Strobe[0] which varies the frequency of the transmitted light and measures the freq and phase delay of the returning light rather than straight delay. I believe this design still qualifies as LIDAR, just with significantly worse performance than a typical system. [0] https://spectrum.ieee.org/cars-that-think/transportation/self-driving/gm-cruise-snaps-up-solidstate-lidar-pioneer-strobe-inc https://spectrum.ieee.org/cars-that-think/transportation/sel...
kersny 9y ago
Joe Grand developed a similar product for Parallax a while back, with a lot of interesting technical details on his site: http://www.grandideastudio.com/laser-range-finder/ http://www.grandideastudio.com/laser-range-finder/
- gregsadetsky 9y ago
  The laser range finder you linked to is different than the OP's 360 degree scanning LIDAR (... as the former doesn't scan!) :-)
inetknght 9y ago
What is the maximum range of this?
- dbcurtis 9y ago
  Well, do you want an eye-safe laser? And want to operate outdoors? The Neato is about 5m indoors, 2m outdoors with a sun shade. That reflects a lot of effort fighting the "sun blindness" problem that having a powerful IR source shining in through your picture window causes for the vacuum cleaner. Practically, you want to modulate the laser so that you can filter for an AC signal.
  - Gibbon1 9y ago
    > "sun blindness" problem that having a powerful IR source. Just point out it's not as bad as one would think since sunlight has much less IR than visible light energy. The deeper IR you can go and the narrower your filters on the receiving side the better. Other issue I had dealing with an IR comm link 30 years ago was it sucks compared to RF because your sensor aperture is very small compared to an antenna. And as you mentioned the the ground floor is much higher with IR than RF.
bri3d 9y ago
This is the same low-cost triangulation approach used in other inexpensive laser rangefinders, like the one on a Neato vacuum: https://www.diva-portal.org/smash/get/diva2:995686/FULLTEXT01.pdf https://www.diva-portal.org/smash/get/diva2:995686/FULLTEXT0... It's dramatically different from the $20k+ LIDAR units you'd find on a self-driving car, which generally use time-of-flight.
- markshead 9y ago
  Also dramatically different than the low cost $13.95 time-of-flight sensors. (https://www.adafruit.com/product/3316 https://www.adafruit.com/product/3316)
  - Animats 9y ago
    Now that's a nice device, and is a true time of flight sensor. There's a similar model with 1.2m range.[1] Don't know whether it's a pulse LIDAR or an RF-modulated beam. The ones that use a pulse laser can have much more range and can work outdoors. They must far outshine the sun, but only at one wavelength and only for a nanosecond. That's quite possible. [1] https://www.adafruit.com/product/3317 https://www.adafruit.com/product/3317
    - antoinealb 9y ago
      According to the VL53L0X datasheet: > During the ranging operation, several VCSEL infrared pulses are emitted, then reflected back by the target object, and detected by the receiving array. VCSEL is Vertical cavity surface emitting laser. Therefore I would say a pulse laser.
    - fest 9y ago
      That one detects phase difference of the reflected signal.
      - Groxx 9y ago
        >The VL6180X can detect the "time of flight", or how long the laser light has taken to bounce back to the sensor. Sounds like no?
ausjke 9y ago
nice, high quality LIDAR are quite expensive for any robots still.
syntaxing 9y ago
This is super awesome! I've been taking Udacity's SDC and I wanted to play with some LIDAR mapping on my own. Been debating for the longest time to get the Neato XV-21 LIDAR but it doesn't really make sense to get an obsolete hardware that people salvage from old vacuums. I wish s/he will sell the PCB on a crowd-funded run like Crowd-Supply or Tindie
- jotux 9y ago
  You can buy 360 degree lidar dev kits for a few hundred dollars: https://www.seeedstudio.com/RPLiDAR-A2M8-Laser-Scanner-Dev-Kit-with-Adapter-Certification-p-3000.html https://www.seeedstudio.com/RPLiDAR-A2M8-Laser-Scanner-Dev-K... https://www.seeedstudio.com/RPLIDAR-360-degree-Laser-Scanner-Development-Kit-p-1823.html https://www.seeedstudio.com/RPLIDAR-360-degree-Laser-Scanner...
  - syntaxing 9y ago
    I was going to buy the RPLidar when they did a fire sale on the first generation. But I read there was some refresh rate error so I didn't pull the trigger. Do you know if the Sweep (by Scanse) is comparable to the RPLidar (Dev version)?
    - Jack000 9y ago
      it is not, afaik. The sweep has greater range in theory but its data is much noisier.
ris 9y ago
This is not LIDAR.
- naikrovek 9y ago
  It isn't time of flight, but I'd say that it is lidar.
  - ris 9y ago
    No. I'm sure that you could argue that technically, if you go by the literal acronym, it is "LIDAR", I really don't think that flies. When you use the term LIDAR, you imply a certain amount of robustness and error rejection you only get using ToF. Sticking the same parallax technology people have been using since the 80s on a board and calling it "LIDAR" isn't really honest.
wotbbcicxinu 9y ago
Shipped with a ROS driver?? I love you. I’ve beeen stuck on v1 Xbox 360 kinects. Ima build this immediately.
- photojosh 9y ago
  The new Intel Realsense D435 is giving us fantastic data, and I've got two of them plugged into ROS.
  - voxadam 9y ago
    This is great to hear. The new D400 devices look quite promising on paper but I have seen virtually no 3rd party reports on how well they perform in the real world. Are you using the D435 outdoors as well?
    - photojosh 9y ago
      We've only done some quick tests outdoors for now, as our device will only operate indoors. But it works well, even when pointed into the sun. Email in profile, send me a message if you want some sample video.
rajangdavis 9y ago
Can Lidar provide the topography of a sidewalk?
- joshvm 9y ago
  Yes, but this system won't. It's an infrared triangulation system, not a LIDAR and at 780nm it probably won't work outdoors.
kalimatas 9y ago
It's kinda surprising to find comments in Russian in code :) https://github.com/iliasam/OpenSimpleLidar/blob/master/Firmware/lidar4_main_code/encoder_handler.c#L32 https://github.com/iliasam/OpenSimpleLidar/blob/master/Firmw...
- BWStearns 9y ago
  It just translates the code above it into Russian (or perhaps the one above translates it into English?).
flyingcircus3 9y ago
There's also a company called Scanse that has a very affordable LIDAR unit, and a ROS driver. Not open source hardware, but at $350, a pretty good deal. They use the Garmin Lidar Lite v3, which has an I2C interface, and all measurements are actually computed in the sensor. The sensor itself is around $120. They also use a shaftless gimbal motor, with a slip ring, which allows for continuous rotation. scanse.io They were also generous enough to leave an exploded CAD model of their design on their kickstarter page, about halfway down, just in case you wanted to see whats going on inside, or perhaps make your own, as its mostly commercial off the shelf parts, with a custom PCB to control the motor. https://www.kickstarter.com/projects/scanse/sweep-scanning-lidar https://www.kickstarter.com/projects/scanse/sweep-scanning-l...
albemuth 9y ago
Having only played with simple breadboard stuff years ago, could someone explain how the wiring works when connecting to something that's spinning? edit: found it in case anyone was curious: https://en.wikipedia.org/wiki/Slip_ring https://en.wikipedia.org/wiki/Slip_ring
- flyingcircus3 9y ago
  They use a slipring. In some ways, its kind of ironic, because these are now most prevalent in brushless DC motors. Slip rings work in the same fashion as brushed motors. To achieve continuous rotation in a brushed motor, there are carbon brushes that are closing different circuits as the rotor spins. This allows the phase of the electricity to stay constantly ahead of the phase of the motor, giving it its acceleration. In a brushless DC motor, this same effect is achieved through a feedback loop, obviating the need for the brushes, which wear over time, and leave carbon deposits. https://www.sparkfun.com/products/13064 https://www.sparkfun.com/products/13064
  - gugagore 9y ago
    another option, if your power and signals aren't too low frequency: https://en.wikipedia.org/wiki/Rotary_transformer https://en.wikipedia.org/wiki/Rotary_transformer
- amelius 9y ago
  It's basically how an electric train does it.
- taneq 9y ago
  Slip rings are noisy and wear out. A lot of scanning LIDAR systems use a rotating mirror with stationary electronics to avoid them. You could also use stationary magnets with coils on the rotating part to transmit power (basically a mini-alternator on the spinning side), and IrDA or something to communicate.
  - dbcurtis 9y ago
    Exactly what the Neato 2nd gen does. Coils for power and IrDA for data.
flyingcircus3 9y ago
With the latest Tesla crash in the news, seeing the point cloud got me thinking. Since mirrors do not create the specular reflections required for LIDAR to work, does this mean a box truck covered in mirrors would be able to render at least the LIDAR portion of an autonomous vehicle useless? Sounds like an attack vector to me.
- web007 9y ago
  It would only apply to a mirror that's offset to point your LiDAR to the sky or at some odd angle. If it's a flat mirror, it will just see itself approaching from 2x the distance / speed between the car and mirror.
  - flyingcircus3 9y ago
    Do I interpret your comment correctly as saying there is some redundant system that is specifically looking for anomalies in sensor readings? Would a top of the line lidar system be able to "understand" that its current inputs were resulting in erroneous outputs? I am reminded of one of the recent Japanese satellites that was effectively an infant mortality, because of some quirk in its redundant systems. I've forgotten the details, but more or less, there were cascading failures across a primary system, its secondary redundancy, and its tertiary redundancy. So the feedback loops designed by the engineers to be negative, and mitigating, ended up being positive, and therefore aggravating, in the cruel vacuum of space. It came down to some error in an orientation sensor, and somehow, the redundant system actually ended up relying on information from the primary system. The boosters designed to slow down the rotation relied on the notion of the satellite's actual rotation, according to the original sensor. As the story goes "Does the machine ever give the right answer given the wrong inputs, Mr Babbage?" Nearly 200 years later, we may finally becoming around to seeing that the woman that asked the question had a point, and Charles simply dismissed it out of hand.
    - web007 9y ago
      I'm only suggesting that mirrors work both ways. If you stand 1m away from a mirror, you will see "yourself" 2m away as a reflection. (1m you:mirror + 1m mirror:reflection) If you move 1m backward, you will see the reflection now 4m away (2m you:mirror + 2m mirror:reflection). Speed works the same way, if you step toward the mirror at 1m/s your reflection will approach you at 2m/s. The same thing applies to LiDAR, either it sees the mirror and calculates the proper distance, or it sees the things reflected in the mirror at 2x actual distance and/or 2x relative speed.
amelius 9y ago
What happens when someone looks into the laser? Is the damage cumulative?
- swiley 9y ago
  I've been told retinal damage from exposure to IR usually is cumulative.
- lucb1e 9y ago
  The thing you're looking for is the class of the laser. Class 1 is completely harmless, class 2 is harmless unless you intentionally stare at it, class 3 is immediately harmful and class 4 is the kind of laser that cuts bone and metal. I'm not sure what class this is, but it should be mentioned somewhere.
  - gregsadetsky 9y ago
    The BOM[0] specifies that this is a "3mw 780nm Infrared IR Diode Laser" with a link to eBay[1]. I'm finding 780nm 2.5mw and 3mw laser diodes rated at classes 3B and 3R. See [2] and [3]. The 3B class rating is given for a high end Edmund Optics laser which most probably gives out the "full" 3mW. A 3B class laser is "hazardous for eye exposure" [4]. So... hard to say, but not great? I fondly remember a sticker that was on a lab's (very scary) laser: "Do not look into laser with remaining eye"... [0] https://github.com/iliasam/OpenSimpleLidar/blob/master/TotalBOM.xlsx https://github.com/iliasam/OpenSimpleLidar/blob/master/Total... (XLS file) [1] https://www.ebay.com/itm/322300023463 https://www.ebay.com/itm/322300023463 [2] https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1487#7796 https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=14... [3] https://www.edmundoptics.com/lasers/laser-sources/780nm-3.0mw-modulation-elliptical-beam-laser-diode-module/ https://www.edmundoptics.com/lasers/laser-sources/780nm-3.0m... [4] http://www.lasersafetyfacts.com/3B/ http://www.lasersafetyfacts.com/3B/
gene-h 9y ago
The scan rate and accuracy may not be the best, but the fact that they are using a linear photodiode array impresses me. The fact they were able to do all this for $35 is even more impressive, and I await the day I can purchase this from chinese electronics hobbyist websites.
- lucb1e 9y ago
  Me too! I've been looking for something like this, but wasn't been able to find anything. Very nice to see this here, perhaps I'll build one if I have time at some point, or order one if it becomes available.
pressurefree 9y ago
use a "phone cord detangler"
edhu2017 9y ago
As somebody with software engineering experience but little hardware experience, how do I get started with building my own Lidar? I notice he provides STL files for base plates and a component list https://hackaday.io/project/20628/components https://hackaday.io/project/20628/components. Still not too sure how to start though.
- gregsadetsky 9y ago
  There's a bit of work, especially on the PCB side (there are 3 separate ones). You would have to order PCBs based on the Gerber files, and all of the components, and have a way of soldering them (they are "surface mount", which adds to the complexity). Overall, it would be much easier if the "final" PCBs were sold as a kit. Assembling this kit would be much easier (and fun) then starting from scratch.
  - sannee 9y ago
    > Assembling this kit would be much easier (and fun) then starting from scratch. What is so fun on assembling a kit? The populate-the-PCB is probably the most mind-numbing part of the whole hardware engineering business. Design and debugging is where it's at
iliasam 9y ago
Hi everyone. I am the author of the OpenSimpleLidar. If you have any questions about this project, you can ask them here. Here is another my Lidar project: https://github.com/iliasam/OpenLIDAR https://github.com/iliasam/OpenLIDAR That project has a wiki: https://github.com/iliasam/OpenLIDAR/wiki https://github.com/iliasam/OpenLIDAR/wiki A big article in Russian about it: https://geektimes.ru/post/275442/ https://geektimes.ru/post/275442/
EgoIncarnate 9y ago
Seems... dangerous? Project states it uses "3mw 780nm Infrared IR Diode Laser". 3mw is enough to damage your eye if you don't blink or turn away. Since it's infrared, you won't blink, or possible even notice anything (there are no pain receptors in the retina) until it's too late. Wikipedia list "780–1400 nm (near-IR) - Pathological effect: cataract, retinal burn"
- yonkshi 9y ago
  In the US 5mW is the legal limit for laser pointers. I think that can be used as a guideline, 3mW IR is much less energetic than a 5mW green/blue laser, perhaps it's not powerful enough to cause huge concern? But I agree no amount of laser is safe for the eye. Police LIDAR guns are 905nm at 50mW, that can technically damage you too. https://en.wikipedia.org/wiki/LIDAR_traffic_enforcement#How_it_works https://en.wikipedia.org/wiki/LIDAR_traffic_enforcement#How_...
  - vanderZwan 9y ago
    Wouldn't it matter how narrow the laser beam is? 50mW spread out over a larger surface area sounds like it should be safer. Of course, then the question is whether that also comes with an equal reduction in sensitivity, or whether a larger sensor can compensate for that.
  - tsukikage 9y ago
    The limit for visible light is as high as it is because of the blink reflex. An IR laser, having a beam you don't perceive as being bright, won't make you blink.
- iliasam 9y ago
  Laser is rotating fast enough so it is less dangerous. Also laser current is modulated, so laser's average power decreased twice.
  - eyeing_see 9y ago
    Which safeguards are implemented to detect that rotation and modulation are taking place as intended?
MasterScrat 9y ago
A cool project would be an autonomous LIDAR-enabled vacuum cleaner, that would actually map out the room it's cleaning to optimize its path.
- iliasam 9y ago
  Neato and Xiaomi vacuum cleaners have integrated Lidars.
dalore 9y ago
My flatmate has a robot and he has a laser that does 3d scanning of a room, pretty much like this but 3d.
rqs 9y ago
Dig little deeper on Youtube: https://www.youtube.com/user/iliasam3/videos https://www.youtube.com/user/iliasam3/videos Awesome!
pette 9y ago
Did the same exact thing back in 2015 that used the omnivision sensor in wiimotes, having the benefit that the sensor readily reports the position of detected infrared spots, so no cpu-heavy postprocessing needed. The 20MHz clock for the sensor was taken from CLKOUT from the controlling avr cpu, so only three parts on the rotating part (laser, cpu, sensor). I would recommend adding a slit and a bandgap filter to reduce the amount of non-laserlight, because i had big problems with false positives from stray light (sunlight etc).

605 points by lovelearning 9y ago

Thanks for this. When I first started working in LiDAR nearly ten years ago the cheapest hardware you could acquire was $25,000 and completely proprietary. It’s nice to see a simple hardware hack for playing with the technology. Maybe this will encourage some intrepid engineers to build the next wave of hobbyist point cloud collection devices. There are lots of fun applications like home surveying to 3D model generation.

rburhum 9y ago
Velodyne?
- rtkwe 9y ago
  Personally, anywhere I can't see a price without contacting a sales rep from the company I hesitate to call hobbyist.
  - nix0n 9y ago
    I agree, definitely not for hobbyists. List price seems to be $8,000 if you're just buying one of their cheapest product. http://velodynelidar.com/docs/news/This%20Palm-Sized%20Laser%20Could%20Make%20Self-Driving%20Cars%20Way%20Cheaper%20_%20WIRED.pdf http://velodynelidar.com/docs/news/This%20Palm-Sized%20Laser...
  - drharby 9y ago
    Eh some motors i needed for building an r2 droid came from such a site. But yes on the whole i concur
- michaelt 9y ago
  At the time Velodyne brought out their HDL-64E for ~$75,000 you could buy a SICK LMS-200 for about 10% of that. That's why loads of the DARPA Grand Challenge vehicles were plastered in SICK LIDARs [1] back when Velodyne only had one prototype, and it was on a truck they were putting in the competition themselves [2]. Course, Velodyne's product may be 10x the cost, but it has 64x the number of lasers, and good range and direct sunlight performance, so it's understandable that it took off. [1] https://www.alamy.com/stock-photo-sep-28-2005-fontana-ca-usa-autonomous-team-vehicles-before-the-start-64082198.html https://www.alamy.com/stock-photo-sep-28-2005-fontana-ca-usa... [2] https://www.popsci.com/scitech/article/2005-10/popscis-darpa-grand-challenge-preview-update-2 https://www.popsci.com/scitech/article/2005-10/popscis-darpa...
beambot 9y ago
10 years ago was 2008. You could buy a Hokuyo for under $3k back then. Now depth cameras were a different story. SwissRanger was $10-15k, but were usurped by the sub-$200 Kinect just a few years later.

jbob2000 9y ago

Oh man this is cool! Now we just need OpenSimpleLaserWindow and we can listen to conversations and track people's movements just like the CIA! I forget where I read about this, but essentially, as you speak, your sound waves vibrate nearby windows, and these vibrations can be picked up with a laser and translated back into sound.

godelski 9y ago
There's a few ways you can do this. The cheapest is to just get a laser and a photo diode. It's rough, but you can get sounds. An interferometer works better. It's harder to make and more expensive, but in the hobby range, at least to get decent quality. There's tons of videos and documents that you can find showing you how to make either. You can also do a lot of cool measurements with these setups
- jbob2000 9y ago
  I had never heard of an interferometer, it actually sounds like something out of a movie haha. Thanks for sharing!
  - deleted 9y ago
    [deleted]
  - godelski 9y ago
    The design is extremely simple. The hard part is aligning things. That's actually the hard part about most optics. If you're really OCD you need to be even more. Here's a little animation of one: https://www.youtube.com/watch?v=UA1qG7Fjc2A https://www.youtube.com/watch?v=UA1qG7Fjc2A
deleted 9y ago
[deleted]

atomical 9y ago

Pretty cool. This could be a good primer for Uber devs.

SlowRobotAhead 9y ago
Last article that was talking about Uber I asked why LIDAR wouldn’t have lit up that lady up. The response was “LIDAR might have been disabled”... as if that was any sort of acceptable scenario.
- deleted 9y ago
  [deleted]
- rootusrootus 9y ago
  Running without LIDAR, at night especially? If that is true, I can imagine that's why they paid off the family so quickly.
- callumjones 9y ago
  It could be related to the fact that LIDAR tech was supposedly stolen from Waymo. Source: http://money.cnn.com/2018/02/07/technology/waymo-v-uber-technology/index.html http://money.cnn.com/2018/02/07/technology/waymo-v-uber-tech...
- icebraining 9y ago
  They have one (compared to Waymo's six): https://www.reuters.com/article/us-uber-selfdriving-sensors-insight/ubers-use-of-fewer-safety-sensors-prompts-questions-after-arizona-crash-idUSKBN1H337Q?il=0 https://www.reuters.com/article/us-uber-selfdriving-sensors-...
- imh 9y ago
  "Because I was driving with my eyes closed" or "Because I wasn't looking" would be the human equivalent. Imagine if the driver used the same excuse, when asked why she didn't see the pedestrian and take over.
  - 9y ago

le-mark 9y ago

What kind of precision can you get with a device like this? The image on the github page looks very imprecise, like on the order of cm of error. If one were to scan a 3d model, could one get sub millimeter resoluton for example?

rubenbe 9y ago
According to the hackaday page [0], the precision is indeed in the order of centimeters: 5 cm at 2 m and 10 cm at 3 m. [0] https://hackaday.io/project/20628-open-simple-lidar https://hackaday.io/project/20628-open-simple-lidar
- dbcurtis 9y ago
  The Neato sensor does anlittle better, about 2cm at 5m

4ff618 9y ago

I really want to know the math behind the triangulation process

danielvf 9y ago
You know the angle of light entering the lens. The tangent of that angle gives you the ratio of (the distance between the lens and the laser) and (distance between the laser and the target). Which lets you work out the distance between the laser and target. Trigonometry rocks!
11235813213455 9y ago
generalized Pythagorean theorem

donquichotte 9y ago

I still don't quite understand how this works. Main components are: - Laser - Lens - TSL1401 line image sensor I was always under the impression that LIDAR includes a time-of-flight measurement, which does not appear to be the case here - the TSL1401 sensor has integration times and pixel transfer times in the range of dozens of microseconds, a timespan in which light travels dozens of kilometers.

fisherjeff 9y ago
Based on the diagram, I believe they're estimating distance based on parallax rather than time of flight
- donquichotte 9y ago
  I agree. The wikipedia article on LIDAR says "Lidar [...] combine[s] laser-focused imaging with the ability to calculate distances by measuring the time for a signal to return using appropriate sensors and data acquisition electronics." So this is not LIDAR. Still impressive though, I love the simplicity!
  - rtkwe 9y ago
    That's probably an overly specific definition. Their source for the lidar definition is a NOAA webpage [0] with a broader definition that doesn't include specifics about implementation: > LIDAR, which stands for Light Detection and Ranging, is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances) to the Earth. Most lidar does use timing but I'd argue that's a type of implementation instead of a necessary part of the broader category of lidar devices. [0] https://www.webcitation.org/6H82i1Gfx?url=http://oceanservice.noaa.gov/facts/lidar.html https://www.webcitation.org/6H82i1Gfx?url=http://oceanservic...
  - adamweld 9y ago
    The LIDAR acronym doesn't specify the specific measurement technique, although Time Of Flight is by far the most common. There are other designs with interesting differences, for example Strobe[0] which varies the frequency of the transmitted light and measures the freq and phase delay of the returning light rather than straight delay. I believe this design still qualifies as LIDAR, just with significantly worse performance than a typical system. [0] https://spectrum.ieee.org/cars-that-think/transportation/self-driving/gm-cruise-snaps-up-solidstate-lidar-pioneer-strobe-inc https://spectrum.ieee.org/cars-that-think/transportation/sel...

kersny 9y ago

Joe Grand developed a similar product for Parallax a while back, with a lot of interesting technical details on his site: http://www.grandideastudio.com/laser-range-finder/ http://www.grandideastudio.com/laser-range-finder/

gregsadetsky 9y ago
The laser range finder you linked to is different than the OP's 360 degree scanning LIDAR (... as the former doesn't scan!) :-)

inetknght 9y ago

What is the maximum range of this?

dbcurtis 9y ago
Well, do you want an eye-safe laser? And want to operate outdoors? The Neato is about 5m indoors, 2m outdoors with a sun shade. That reflects a lot of effort fighting the "sun blindness" problem that having a powerful IR source shining in through your picture window causes for the vacuum cleaner. Practically, you want to modulate the laser so that you can filter for an AC signal.
- Gibbon1 9y ago
  > "sun blindness" problem that having a powerful IR source. Just point out it's not as bad as one would think since sunlight has much less IR than visible light energy. The deeper IR you can go and the narrower your filters on the receiving side the better. Other issue I had dealing with an IR comm link 30 years ago was it sucks compared to RF because your sensor aperture is very small compared to an antenna. And as you mentioned the the ground floor is much higher with IR than RF.

bri3d 9y ago

This is the same low-cost triangulation approach used in other inexpensive laser rangefinders, like the one on a Neato vacuum: https://www.diva-portal.org/smash/get/diva2:995686/FULLTEXT01.pdf https://www.diva-portal.org/smash/get/diva2:995686/FULLTEXT0... It's dramatically different from the $20k+ LIDAR units you'd find on a self-driving car, which generally use time-of-flight.

markshead 9y ago
Also dramatically different than the low cost $13.95 time-of-flight sensors. (https://www.adafruit.com/product/3316 https://www.adafruit.com/product/3316)
- Animats 9y ago
  Now that's a nice device, and is a true time of flight sensor. There's a similar model with 1.2m range.[1] Don't know whether it's a pulse LIDAR or an RF-modulated beam. The ones that use a pulse laser can have much more range and can work outdoors. They must far outshine the sun, but only at one wavelength and only for a nanosecond. That's quite possible. [1] https://www.adafruit.com/product/3317 https://www.adafruit.com/product/3317
  - antoinealb 9y ago
    According to the VL53L0X datasheet: > During the ranging operation, several VCSEL infrared pulses are emitted, then reflected back by the target object, and detected by the receiving array. VCSEL is Vertical cavity surface emitting laser. Therefore I would say a pulse laser.
  - fest 9y ago
    That one detects phase difference of the reflected signal.
    - Groxx 9y ago
      >The VL6180X can detect the "time of flight", or how long the laser light has taken to bounce back to the sensor. Sounds like no?

ausjke 9y ago

nice, high quality LIDAR are quite expensive for any robots still.

syntaxing 9y ago

This is super awesome! I've been taking Udacity's SDC and I wanted to play with some LIDAR mapping on my own. Been debating for the longest time to get the Neato XV-21 LIDAR but it doesn't really make sense to get an obsolete hardware that people salvage from old vacuums. I wish s/he will sell the PCB on a crowd-funded run like Crowd-Supply or Tindie

jotux 9y ago
You can buy 360 degree lidar dev kits for a few hundred dollars: https://www.seeedstudio.com/RPLiDAR-A2M8-Laser-Scanner-Dev-Kit-with-Adapter-Certification-p-3000.html https://www.seeedstudio.com/RPLiDAR-A2M8-Laser-Scanner-Dev-K... https://www.seeedstudio.com/RPLIDAR-360-degree-Laser-Scanner-Development-Kit-p-1823.html https://www.seeedstudio.com/RPLIDAR-360-degree-Laser-Scanner...
- syntaxing 9y ago
  I was going to buy the RPLidar when they did a fire sale on the first generation. But I read there was some refresh rate error so I didn't pull the trigger. Do you know if the Sweep (by Scanse) is comparable to the RPLidar (Dev version)?
  - Jack000 9y ago
    it is not, afaik. The sweep has greater range in theory but its data is much noisier.

ris 9y ago

This is not LIDAR.

naikrovek 9y ago
It isn't time of flight, but I'd say that it is lidar.
- ris 9y ago
  No. I'm sure that you could argue that technically, if you go by the literal acronym, it is "LIDAR", I really don't think that flies. When you use the term LIDAR, you imply a certain amount of robustness and error rejection you only get using ToF. Sticking the same parallax technology people have been using since the 80s on a board and calling it "LIDAR" isn't really honest.

wotbbcicxinu 9y ago

Shipped with a ROS driver?? I love you. I’ve beeen stuck on v1 Xbox 360 kinects. Ima build this immediately.

photojosh 9y ago
The new Intel Realsense D435 is giving us fantastic data, and I've got two of them plugged into ROS.
- voxadam 9y ago
  This is great to hear. The new D400 devices look quite promising on paper but I have seen virtually no 3rd party reports on how well they perform in the real world. Are you using the D435 outdoors as well?
  - photojosh 9y ago
    We've only done some quick tests outdoors for now, as our device will only operate indoors. But it works well, even when pointed into the sun. Email in profile, send me a message if you want some sample video.

rajangdavis 9y ago

Can Lidar provide the topography of a sidewalk?

joshvm 9y ago
Yes, but this system won't. It's an infrared triangulation system, not a LIDAR and at 780nm it probably won't work outdoors.

kalimatas 9y ago

It's kinda surprising to find comments in Russian in code :) https://github.com/iliasam/OpenSimpleLidar/blob/master/Firmware/lidar4_main_code/encoder_handler.c#L32 https://github.com/iliasam/OpenSimpleLidar/blob/master/Firmw...

BWStearns 9y ago
It just translates the code above it into Russian (or perhaps the one above translates it into English?).

flyingcircus3 9y ago

There's also a company called Scanse that has a very affordable LIDAR unit, and a ROS driver. Not open source hardware, but at $350, a pretty good deal. They use the Garmin Lidar Lite v3, which has an I2C interface, and all measurements are actually computed in the sensor. The sensor itself is around $120. They also use a shaftless gimbal motor, with a slip ring, which allows for continuous rotation. scanse.io They were also generous enough to leave an exploded CAD model of their design on their kickstarter page, about halfway down, just in case you wanted to see whats going on inside, or perhaps make your own, as its mostly commercial off the shelf parts, with a custom PCB to control the motor. https://www.kickstarter.com/projects/scanse/sweep-scanning-lidar https://www.kickstarter.com/projects/scanse/sweep-scanning-l...

albemuth 9y ago

Having only played with simple breadboard stuff years ago, could someone explain how the wiring works when connecting to something that's spinning? edit: found it in case anyone was curious: https://en.wikipedia.org/wiki/Slip_ring https://en.wikipedia.org/wiki/Slip_ring

flyingcircus3 9y ago
They use a slipring. In some ways, its kind of ironic, because these are now most prevalent in brushless DC motors. Slip rings work in the same fashion as brushed motors. To achieve continuous rotation in a brushed motor, there are carbon brushes that are closing different circuits as the rotor spins. This allows the phase of the electricity to stay constantly ahead of the phase of the motor, giving it its acceleration. In a brushless DC motor, this same effect is achieved through a feedback loop, obviating the need for the brushes, which wear over time, and leave carbon deposits. https://www.sparkfun.com/products/13064 https://www.sparkfun.com/products/13064
- gugagore 9y ago
  another option, if your power and signals aren't too low frequency: https://en.wikipedia.org/wiki/Rotary_transformer https://en.wikipedia.org/wiki/Rotary_transformer
amelius 9y ago
It's basically how an electric train does it.
taneq 9y ago
Slip rings are noisy and wear out. A lot of scanning LIDAR systems use a rotating mirror with stationary electronics to avoid them. You could also use stationary magnets with coils on the rotating part to transmit power (basically a mini-alternator on the spinning side), and IrDA or something to communicate.
- dbcurtis 9y ago
  Exactly what the Neato 2nd gen does. Coils for power and IrDA for data.

flyingcircus3 9y ago

With the latest Tesla crash in the news, seeing the point cloud got me thinking. Since mirrors do not create the specular reflections required for LIDAR to work, does this mean a box truck covered in mirrors would be able to render at least the LIDAR portion of an autonomous vehicle useless? Sounds like an attack vector to me.

web007 9y ago
It would only apply to a mirror that's offset to point your LiDAR to the sky or at some odd angle. If it's a flat mirror, it will just see itself approaching from 2x the distance / speed between the car and mirror.
- flyingcircus3 9y ago
  Do I interpret your comment correctly as saying there is some redundant system that is specifically looking for anomalies in sensor readings? Would a top of the line lidar system be able to "understand" that its current inputs were resulting in erroneous outputs? I am reminded of one of the recent Japanese satellites that was effectively an infant mortality, because of some quirk in its redundant systems. I've forgotten the details, but more or less, there were cascading failures across a primary system, its secondary redundancy, and its tertiary redundancy. So the feedback loops designed by the engineers to be negative, and mitigating, ended up being positive, and therefore aggravating, in the cruel vacuum of space. It came down to some error in an orientation sensor, and somehow, the redundant system actually ended up relying on information from the primary system. The boosters designed to slow down the rotation relied on the notion of the satellite's actual rotation, according to the original sensor. As the story goes "Does the machine ever give the right answer given the wrong inputs, Mr Babbage?" Nearly 200 years later, we may finally becoming around to seeing that the woman that asked the question had a point, and Charles simply dismissed it out of hand.
  - web007 9y ago
    I'm only suggesting that mirrors work both ways. If you stand 1m away from a mirror, you will see "yourself" 2m away as a reflection. (1m you:mirror + 1m mirror:reflection) If you move 1m backward, you will see the reflection now 4m away (2m you:mirror + 2m mirror:reflection). Speed works the same way, if you step toward the mirror at 1m/s your reflection will approach you at 2m/s. The same thing applies to LiDAR, either it sees the mirror and calculates the proper distance, or it sees the things reflected in the mirror at 2x actual distance and/or 2x relative speed.

amelius 9y ago

What happens when someone looks into the laser? Is the damage cumulative?

swiley 9y ago
I've been told retinal damage from exposure to IR usually is cumulative.
lucb1e 9y ago
The thing you're looking for is the class of the laser. Class 1 is completely harmless, class 2 is harmless unless you intentionally stare at it, class 3 is immediately harmful and class 4 is the kind of laser that cuts bone and metal. I'm not sure what class this is, but it should be mentioned somewhere.
- gregsadetsky 9y ago
  The BOM[0] specifies that this is a "3mw 780nm Infrared IR Diode Laser" with a link to eBay[1]. I'm finding 780nm 2.5mw and 3mw laser diodes rated at classes 3B and 3R. See [2] and [3]. The 3B class rating is given for a high end Edmund Optics laser which most probably gives out the "full" 3mW. A 3B class laser is "hazardous for eye exposure" [4]. So... hard to say, but not great? I fondly remember a sticker that was on a lab's (very scary) laser: "Do not look into laser with remaining eye"... [0] https://github.com/iliasam/OpenSimpleLidar/blob/master/TotalBOM.xlsx https://github.com/iliasam/OpenSimpleLidar/blob/master/Total... (XLS file) [1] https://www.ebay.com/itm/322300023463 https://www.ebay.com/itm/322300023463 [2] https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1487#7796 https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=14... [3] https://www.edmundoptics.com/lasers/laser-sources/780nm-3.0mw-modulation-elliptical-beam-laser-diode-module/ https://www.edmundoptics.com/lasers/laser-sources/780nm-3.0m... [4] http://www.lasersafetyfacts.com/3B/ http://www.lasersafetyfacts.com/3B/

gene-h 9y ago

The scan rate and accuracy may not be the best, but the fact that they are using a linear photodiode array impresses me. The fact they were able to do all this for $35 is even more impressive, and I await the day I can purchase this from chinese electronics hobbyist websites.

lucb1e 9y ago
Me too! I've been looking for something like this, but wasn't been able to find anything. Very nice to see this here, perhaps I'll build one if I have time at some point, or order one if it becomes available.

pressurefree 9y ago

use a "phone cord detangler"

edhu2017 9y ago

As somebody with software engineering experience but little hardware experience, how do I get started with building my own Lidar? I notice he provides STL files for base plates and a component list https://hackaday.io/project/20628/components https://hackaday.io/project/20628/components. Still not too sure how to start though.

gregsadetsky 9y ago
There's a bit of work, especially on the PCB side (there are 3 separate ones). You would have to order PCBs based on the Gerber files, and all of the components, and have a way of soldering them (they are "surface mount", which adds to the complexity). Overall, it would be much easier if the "final" PCBs were sold as a kit. Assembling this kit would be much easier (and fun) then starting from scratch.
- sannee 9y ago
  > Assembling this kit would be much easier (and fun) then starting from scratch. What is so fun on assembling a kit? The populate-the-PCB is probably the most mind-numbing part of the whole hardware engineering business. Design and debugging is where it's at

iliasam 9y ago

Hi everyone. I am the author of the OpenSimpleLidar. If you have any questions about this project, you can ask them here. Here is another my Lidar project: https://github.com/iliasam/OpenLIDAR https://github.com/iliasam/OpenLIDAR That project has a wiki: https://github.com/iliasam/OpenLIDAR/wiki https://github.com/iliasam/OpenLIDAR/wiki A big article in Russian about it: https://geektimes.ru/post/275442/ https://geektimes.ru/post/275442/

EgoIncarnate 9y ago

Seems... dangerous? Project states it uses "3mw 780nm Infrared IR Diode Laser". 3mw is enough to damage your eye if you don't blink or turn away. Since it's infrared, you won't blink, or possible even notice anything (there are no pain receptors in the retina) until it's too late. Wikipedia list "780–1400 nm (near-IR) - Pathological effect: cataract, retinal burn"

yonkshi 9y ago
In the US 5mW is the legal limit for laser pointers. I think that can be used as a guideline, 3mW IR is much less energetic than a 5mW green/blue laser, perhaps it's not powerful enough to cause huge concern? But I agree no amount of laser is safe for the eye. Police LIDAR guns are 905nm at 50mW, that can technically damage you too. https://en.wikipedia.org/wiki/LIDAR_traffic_enforcement#How_it_works https://en.wikipedia.org/wiki/LIDAR_traffic_enforcement#How_...
- vanderZwan 9y ago
  Wouldn't it matter how narrow the laser beam is? 50mW spread out over a larger surface area sounds like it should be safer. Of course, then the question is whether that also comes with an equal reduction in sensitivity, or whether a larger sensor can compensate for that.
- tsukikage 9y ago
  The limit for visible light is as high as it is because of the blink reflex. An IR laser, having a beam you don't perceive as being bright, won't make you blink.
iliasam 9y ago
Laser is rotating fast enough so it is less dangerous. Also laser current is modulated, so laser's average power decreased twice.
- eyeing_see 9y ago
  Which safeguards are implemented to detect that rotation and modulation are taking place as intended?

MasterScrat 9y ago

A cool project would be an autonomous LIDAR-enabled vacuum cleaner, that would actually map out the room it's cleaning to optimize its path.

iliasam 9y ago
Neato and Xiaomi vacuum cleaners have integrated Lidars.

dalore 9y ago

My flatmate has a robot and he has a laser that does 3d scanning of a room, pretty much like this but 3d.

rqs 9y ago

Dig little deeper on Youtube: https://www.youtube.com/user/iliasam3/videos https://www.youtube.com/user/iliasam3/videos Awesome!

pette 9y ago

Did the same exact thing back in 2015 that used the omnivision sensor in wiimotes, having the benefit that the sensor readily reports the position of detected infrared spots, so no cpu-heavy postprocessing needed. The 20MHz clock for the sensor was taken from CLKOUT from the controlling avr cpu, so only three parts on the rotating part (laser, cpu, sensor). I would recommend adding a slit and a bandgap filter to reduce the amount of non-laserlight, because i had big problems with false positives from stray light (sunlight etc).