New Part Day: Very Cheap LIDAR

Self-driving cars are, apparently, the next big thing. This thought is predicated on advancements in machine vision and cheaper, better sensors. For the machine vision part of the equation, Nvidia, Intel, and Google are putting out some interesting bits of hardware. The sensors, though? We’re going to need LIDAR, better distance sensors, more capable CAN bus dongles, and the equipment to tie it all together.

This is the cheapest LIDAR we’ve ever seen. The RPLIDAR is a new product from Seeed Studios, and it’s an affordable LIDAR for everyone. $400 USD gets you one module, and bizarrely $358 USD gets you two modules. Don’t ask questions — this price point was unheard of a mere five years ago.

Basically, this LIDAR unit is a spinning module connected to a motor via a belt. A laser range finder is hidden in the spinny bits and connected to a UART and USB interface through a slip ring. Mount this LIDAR unit on a robot, apply power, and the spinny bit does its thing at about 400-500 RPM. The tata that comes out includes distance (in millimeters), bearing (in units of degrees), quality of the measurement, and a start flag once every time the head makes a revolution. If you’ve never converted polar to cartesian coordinates, this is a great place to start.

Although self-driving cars and selfie drones are the future, this part is probably unsuitable for any project with sufficient mass or velocity. The scanning range of this LIDAR is only about 6 meters and insufficient for retrofitting a Toyota Camry with artificial intelligence. That said, this is a cheap LIDAR that opens the door to a lot of experimentation ranging from small robots to recreating that one Radiohead video.

67 thoughts on “New Part Day: Very Cheap LIDAR

    1. Check out the $40 LIDAR units from China. We have several of them. Range up to 60m. Acquisition rate not as high or trade off accuracy vs.rate. Reliable. Manuals are typical People’s Republic, but dirt simple to figure out. Can get them for as low as $33 in volume of 10 or more. Lidar-lite worked well in the lab, but awful in the field. And at $140???

        1. Not OP, but the closest thing I can find is this https://www.aliexpress.com/item/Fast-Free-Ship-USB-TTL-STC-ISP-51-SCM-Phase-Serial-Port-output-laser-range-finder/32730428396.html

          Seems pretty promising. I’m sure you could scan it back and forth yourself for less than the remaining $290, if it’s not a critical application.

          I’m not 100% convinced, but I might give them a play when I’ve popped the next 5 projects off my ‘to hack’ pile.

          1. Volumetric map updated with fill in data. Unless you are in a mine or office where perspective blocks most of the view. By the time you get across the room you would have a volumetric map of the room. Once you have the map it’s fill in and reference to movement.

    1. And it came out in 2010, so you could buy a vacuum for $400, shuck it for the sensor, and have a bunch of motors and goodies left over. This price point was interesting 7 years ago, and completely mundane 5 years ago.

      This is still cool because Neato have never sold the sensor by itself, and sometimes it’s hard to explain to your boss why you’re expensing a vacuum cleaner. But it’s hardly revolutionary.

    1. Not if you buy two… the fact is the Lidar costs less than $70 to make… from what I remember (I think someone did a breakdown on the neato sensor cost but I don’t have a link).

        1. while Kinect v1 and by proxy all the PrimeSense based products give you depth field straight up (2D Z-buffer array), Xbox one Kinect requires a TON of math to arrive at the same result, ~ 80 Nvidia shaders of computation.

      1. That one doesn’t scan.

        The Scanse Sweep is basically $200 worth of slip rings and rotating stuff added to what you linked to create a 2-D 360 degree solution – the 1-D ranging solution of the Sweep is a Garmin LIDAR-Lite v3.

        Nowhere near the sampling rate or angular resolution of a SICK/Hokuyo/etc. but FAR cheaper.

        Also the Sweep (if it ever ships, I now consider availability of “Kickstarter” to be below “announced product with no release date) has a range of 40m (same as the Garmin it uses) which is far greater than that of the Neato LIDAR or the RPLIDAR. The RPLIDAR seems to be the closest thing to a “standalone Neato” you can buy. In fact the first-gen units look STRANGELY like Neato cannibalizations/pulls.

      1. Compare also the range, and the fact that the Sweep (claims to) work in sunlight.
        If you want to use it outdoor, the Sweep looks clearly more appropriate.
        This is actually a completely different technology : the RPLIDAR is not technically a LIDAR sensor, but a triangulation system based on laser. The Sweep uses a real LIDAR sensor (apparently a yet unreleased new version of the LidarLite)

    2. This Lidar-Lite is junk. We have two of them and set it up precisely as suggested from Garmin using both I2C and PWM modes, the 680uF cap, etc.. They worked for a while, then constantly lost the link to the processor and will not work very well in the rain, so an indoor, delicate lab toy.

    1. Good point. I have one (old model). It worked great indoors, did not try outdoors. But only for about 10 hours, then it started to lose data. Replaced the slip ring after 20 hours since the unit was useless by then. They clame the new one lasts longer.

    1. Even modern main battle tanks use them and it’s never a problem (and they transfer quite a bit of power and data) :P
      Some proffessional Betacam VCRs used sliprings for the drum, also didn’t seem as much of a problem…

        1. Obviously cost.
          Inductive couplings will always leak interference due to the airgap. You’re still limited by the lifetime of the main bearing, so why add expensive and noise-inducing (read more $$$ in better filtering on both stationary and rotating parts) inductive couplings when there’s still a bearing that will wear out eventually.
          Slip rings are cheap and last surprisingly long at these low speeds, since you’re not transferring a whole lot of power through them. If it had to run at >10k rpm or push a lot of power – absolutely inductive coupling. But at these speeds and power, there’s no benefit, only disadvantages.

      1. Are you sure they used it for the actual head signals? Any other video recorder used inductive coupling. The only slip ring I found in a VCR was in a Video 2000 for the piezo control voltage. This went up to +/-150V and has a DC component. So inductive coupling would have been quite difficult.

        1. I was slightly disappointed with the 6 metre range, then remembered that most motorists only ever look about 3 metres down the road, as long as head moving or putting down their mobile phone isn’t required, so probably an improvement, even if it does only work in the dark.

    1. “Self-driving cars are, apparently, the next big thing.” Translated into the real world, that means they’re unlike to happen for any but specialized situations.

      Also could someone tell me how you make first level comments to these new article streaming webpages. When I get to the bottom of an article in Safari, I don’t get a chance to comment. I get the next article. for thise site, I can at least reply to someone else’s comment, but I can’t start a thread.

      Site after sight has gone for the article streaming madness and all seem to have this problem in one way or another. At some sites, I ever-so-briefly see the comment section before that next page hides it. It is frustrating.

      1. Sometimes you have to select “view desktop version” or “request desktop site”. Also, some pages seem to work best in horizontal mode while others only work vertically. A few weeks ago one of my favorite sites was almost unusable for reading comments, they went for the stupid streaming and the comments disappear if you lose the connection for any reason. :(
        I would joke and say that your problem is using an Apple device… :P
        but it obviously isn’t Apples fault.
        https://www.apple.com/feedback/safari.html

    1. Think of an old television set. It’s ONE trace that is scanning and being modulated against the phosphor screen. The vertical deflection is controlled by a voltage applied to a coil. In this case, you can get your vertical ‘pixels’ by adding a mechanical actuator – a platform – to the mix and use a stepper or similar control mechanism to make the LIDAR assembly point up and down.

  1. How would it be possible to have to or more applications of LIDAR in the same environment. Wouldn’t the sweeping of one effect the detection of another? Just asking for a friend.

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