The ability to inexpensively but accurately measure distance between an autonomous vehicle or robot and nearby objects is a challenging problem for hackers. Knowing the distance is key to obstacle avoidance. Running into something with a small robot may be a trivial problem but could be deadly with a big one like an autonomous vehicle.
My interest in distance measurement for obstacle avoidance stems from my entry in the 2013 NASA Sample Return Robot (SRR) Competition. I used a web camera for vision processing and attempted various visual techniques for making measurements, without a lot of success. At the competition, two entrants used scanning lidars which piqued my interest in them.
Continue reading “How to Use Lidar with the Raspberry Pi”
It seems second nature to us and it’s one of the ways we hackers are different from the larger population… sometimes we absolutely insist on buying something that is already broken. Which is where we join [Anton] as he reverse engineers, debugs, and repairs a broken Neato Botvac’s LiDAR system all in the name of having clean floors at a fraction of the cost.
Now keep your head on a swivel ’cause along the way [Anton] has the all-too familiar point in his repair where he puts the original project on hold while he makes a specialized tool he needs to finish the job. It’s hard to tell which is more impressive: turning a laptop webcam into a camera capable of clearly viewing bond wires and (wait for it!) where they are attached on the Silicon, or that he (yeah, we were making a comparison…member?) went straight back to solving the original problem. [Anton] did split this project into two separate blog posts, the first one is linked above and it’s not until the second post that he fixes the original problem. Perhaps there was a bit of scope creep, which was the reason for the separate blog entries? At any rate, [Anton] does a great job documenting the process along with what he calls some ‘juicy pictures’ and you can see a few of them after the break.
It’s been a while since we’ve seen a Neato hack (there’s pun in there somewhere, commenters below us will surely wipe the floor with it). LiDar on the other hand has been covered more recently in a Police LiDAR Tear Down and another post relating more directly to [Anton’s] repair.
Continue reading “Neato Botvac LiDAR Repair Includes Juicy Pics and a Tool Hack”
Most police departments made a big switch from RADAR to LiDAR after consumers starting buying RADAR detectors. A lot of those LiDAR units are now out there on the surplus market. If you don’t have $500 or so to buy a LiDAR gun just to see what makes it tick, you are in luck. [Alexei Polkhanov] spent an hour tearing down a UltraLyte LTI 20-20 LR 100 so you don’t have to.
An hour seems like a lot for a tear down video, but [Alexei] speeds up through the boring parts, and spends a lot of time talking about the optics and how the device works (with a lot of hand drawn diagrams). He also puts it back together and connects a scope to show the electronic operation of the device.
He mentions the display and control board uses a serial interface to talk to the controller board. There is also an unpopulated header on the main board that is clearly a serial port, probably for reprogramming the onboard microcontroller. With a little reverse engineering work, this LiDAR gun ought to be highly hackable.
In addition to the display and control board, the unit contains a high voltage supply for the laser and the photodiode. Making a power supply to drive the laser that is clean enough not to disturb the sensor is one of the design drivers and it shows. The power supply is a large and complex board by comparison to the other boards in the system.
Continue reading “Police LiDAR Tear Down”
Right now we’re throwing a two-day hackathon in Pasadena. As with all hackathons, people are going to build something, but that’s only going to happen today. Yesterday was an incredible Zero to Product talk that goes over PCB layout techniques, manufacturing, and schematic capture. In a seven hour talk, our own [Matt Berggren] took the audience through building a product, in this case a little ESP8266 breakout board. We livestreamed this; the video (and electric pickles) are below.
Continue reading “How To Make Hardware, With Examples And An Electric Pickle”
[Patrick] has spent a lot of time around ground and aerial based autonomous robots, and over the last few years, he’s noticed a particular need for teams in robotics competitions to break through the ‘sensory bottleneck’ and get good data of the surrounding environment for navigational algorithms. The most well-funded teams in autonomous robotics competitions use LIDARs to scan the environment, but these are astonishingly expensive. With that, [Patrick] set out to create a cheaper solution.
Early this year, [Patrick] learned of an extremely cheap LIDAR sensor. Now [Patrick] is building a robotics distance measurement unit based on this sensor.
Early experiments with mechanically scanned LIDAR sensors centered around the XV-11 LIDAR, the distance sensor found in the Neato Robotics robot vacuum cleaner. [Patrick] became convinced a mechanically scanned LIDAR was the way forward when it came to distance measurement of autonomous robots. Now he’s making his own with an astonishingly inexpensive LIDAR sensor.
The basic idea of [Patrick]’s project is to take the PulsedLight LIDAR-Lite module, add a motor and processing board, and sell a complete unit that will output 360° of distance data to a robot’s main control system. The entire system should cost under $150 when finished; a boon to any students, teams, or hobbyists building an autonomous vehicle.
[Patrick]’s system is based on the PulsedLight LIDAR – a device that’s not shipping yet – but the team behind the LIDAR-Lite says they should have everything ready by the end of the month, all the better, because between these two devices, there’s a lot of cool stuff to be done in the area of autonomous robots.
Lasers are some of the coolest devices around. We can use them to cut things, create laser light shows, and also as a rangefinder.[Ignas] wrote in to tell us about [Berryjam’s] AMAZING write-up on creating an Arduino based laser rangefinder. This post is definitely worth reading.
Inspired by a Arduino based LIDAR system, [Berryjam] decided that he wanted to successfully use an affordable Open Source Laser RangeFinder (OSLRF-01) from LightWare. The article starts off by going over the basics of how to measure distance with a laser based system. You measure the time between an outgoing laser pulse and the reflected return pulse; this time directly relates to the distance of the object. Sounds simple? In practice, it is not as simple as it may seem. [Berryjam] has done a great job doing some real world testing of this device, with nice plots to top it all off. After fiddling with the threshold and some other aspects of the code, the resulting accuracy is quite good.
Recently, we have seen more projects utilizing lasers for range-finding, including LIDAR projects. It is very exciting to see such high-end sensors making their way into the maker/hacker realm. If you have a related laser project, be sure to let us know!
If you need some sort of distance sensor for your robot, drone, or other project, you have two options: a cheap ultrasonic sensor with limited range, or an expensive laser-based system that’s top of the line. LIDAR-Lite fills that gap by stuffing an entire LIDAR module onto a small board.
In traditional LIDAR systems, a laser is used to measure the time of flight for a light beam between the sensor and an object. The very accurate clock and laser module required for this system means LIDAR modules cost at least a few hundred dollars. LIDAR-Lite gets around these problems by blinking a LED with a ‘signature’ and looking for that signature’s return. This tech is packaged inside a SoC that reduces both the cost and size of a traditional laser-based LIDAR system.
As for the LIDAR-Lite specs, it can sense objects out to 40 meters with
5% 95% accuracy, communicates to any microcontroller over an I2C bus, and is small enough to fit inside any project.
Considering the existing solutions for distance measurement for robots and quadcopters, this sensor will certainly make for some very awesome projects.
Edit: One of the guys behind this posted a link to their spec sheet and a patent in the comments