A Mechanically Scanned LIDAR For Autonomous Robots

LIDAR[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.

Pew Pew! An Arduino Based Laser Rangefinder

Arduino Laser Rangefinder
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!

LIDAR With LEDs For Under $100

LIDAR

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

Preserving locomotives with 3D laser scanning and 3D printing

loco

[Chris Thorpe] is a model railroading aficionado, and from his earliest memories he was infatuated with the narrow gauge locomotives that plied their odd steel tracks in northern Wales. Of course [Chris] went on to create model railroads, but kit manufacturers such as Airfix and Hornby didn’t take much interest in the small strange trains of the Ffestiniog railway.

The days where manufacturing plastic models meant paying tens of thousands of dollars in tooling for injection molds are slowly coming to an end thanks to 3D printing, so [Chris] thought it would be a great idea to create his own models of these small locomotives with 3D laser scanners and high quality 3D printers.

[Chris] started a kickstarter to fund a 3D laser scanning expedition to the workshop where the four oldest locomotives of the Ffestiniog railway were being reconditioned for their 150th anniversary. The 3D printed models he’s able to produce with his data have amazing quality; with a bit of paint and a few bits of brass, these models would fit right in to any model railway.

Even better than providing scale narrow gauge engines to model railway enthusiasts around the world is the fact that [Chris] has demonstrated the feasibility of using modern technology to recreate both famous and underappreciated technological relics in plastic for future generations. There’s a lot that can be done with a laser scanner in a railway or air museum or [Jay Leno]‘s garage, so we’d love to see more 3D printed models of engineering achievements make their way onto Kickstarter.

3D gesture tracking with LIDAR

[Reza] has been working on detecting hand gestures with LIDAR for about 10 years now, and we’ve got to say the end result is worth the wait.

The build uses three small LIDAR sensors to measure the distance to an object. These sensors work by sending out an infrared pulse and recording the time of flight for a beam of light to be emmitted and reflected back to a light sensor. Basically, it’s radar but with infrared light. Three of these LIDAR sensors are mounted on a stand and plugged into an Arduino Uno. By measuring how far away an object is to each sensor, [Reza] can determine the object’s position in 3D space relative to the sensor.

Unlike the Kinect-based gesture applications we’ve seen, [Reza]‘s LIDAR can work outside in the sun. Because each LIDAR sensor is measuring the distance a million times a second, it’s also much more responsive than a Kinect as well. Not bad for 10 years worth of work.

You can check out [Reza]‘s gesture control demo, as well as a few demos of his LIDAR hardware after the break.

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Digging deep into the Neato’s LIDAR module

[Hash] is going to great lengths to learn about the parts used in his Neato XV-11 LIDAR. We looked in on his work with the XV-11 platform recently, where he used the dust bin of the vacuum as a modular hardware housing. This hack is a hardware exploration aimed at figuring out how an equivalent open hardware version can be built.

The LIDAR module is made of two big chunks; the laser and optic assembly, and the sensor board seen above. [Hash] put it under the microscope for a better look at the line scan imager. The magnification helped him find the company name on the die, this particular part is manufactured by Panavision. He figured out the actual model by counting the bonding wires and pixels in between them to get a pretty good guess at the resolution. He’s pretty sure it’s a DLIS-2K and links to an app note and the datasheet in his post. The chip to the right of the sensor is a TI digital signal processor.

Putting it back together may prove difficult because it will be impossible to realign the optics exactly as they were–the module will need to be recalibrated. [Hash] plans to investigate how the calibration routines work and he’ll post anything that he finds. Check out his description of the tear down in the video after the break.

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Autonomous cars already drive the roads among us

Google’s showing off this autonomous car at the TED convention right now, but the hardware has already made automated trips from San Fransisco to Los Angeles. According to the commentary in the video after the break, the scene above shows the car “hauling Prius ass” on a closed course. The car learned this route while being driven by a person and now the vehicle is set to take riders through an aggressively driven loop in the cone-adorned parking ramp. But on the open road you do not need to teach it anything. It has no problem taking a GPS route and following the rules of the road while traveling from one waypoint to another.

The link above doesn’t include hardware information but they did point to a Times article which includes an infographic. The spinning box on the top of the car is 3D-mapping LIDAR with a 200 foot radius. There’s a rotary encoder on one of the wheels for precise movement data, radar sensors on the front and back bumpers, and a rear-view-mirror-mounted camera for image processing. It makes us wonder how the system performs when the car is coated in road-muck? Maybe you just add a dedicated wiper for each sensor.

[Read more...]

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