Smartphone and IR Line Laser Measure Distance

Measuring the distance using lasers is a mainstay of self-driving vehicles and ambitious robotics projects. The fine folks at MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) decided to tackle the problem in an innovative way. [Jason H. Gao] and [Li-Shiuan Peh] used an infra-red (IR) line laser and the camera on a smartphone. Their prototype cost only $49 since they used a smartphone that was on hand. The article reports good results using the device outdoors in direct sunlight which is often a challenge for inexpensive lidars.

The line laser creates a horizontal line that is reflected back to the camera on the phone. The vertical position of the laser on the camera image lets the phone calculate the distance by parallax. To bring out a faint laser reflection, the algorithm compares four images – two with the laser on and two with it off – and subtracts the background. Using a smartphone for this is ideal since it automatically adjusts for light level and can easily be upgraded to a newer phone with a better camera later.

This should be a cheap and easily replicable setup. If you make one of these, let us know. If you need something more refined, check out this post on interfacing the Neato vacuum cleaner’s XV-11a lidar with the Raspberry Pi.

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Hackaday Links: March 20, 2016

Western Digital introduced their second revision of the PiDrive this week. This is a native USB hard drive – formatted to 314GB – based on the WD Blue drive. The earlier version of the WD PiDrive was 1TB, and cost about $70 USD. The new, 314GB version, sells for about $35. Does Western Digital manufacture 314GB hard drives? No, that would be stupid. Who’s taking bets on the actual capacity of these drives?

[SopaXorsTaker] has introduced us to a brand new way of removing BGA chips. PCBs are usually more flexible than chips, and a few whacks with a hammer is all that’s needed.

For the last few months, [quarterturn] has been upgrading a PowerBook 520. He’s trying to replace the CPU with a 68040 that has an FPU. His first attempt failed, and his second attempt – a new Freescale part that certainly has an FPU – also failed. It’s great experience in desoldering and reworking fine-pitch QFP parts, but [quarterturn] has no idea why the Apple System Profile reports an FPU-less CPU. It might be something in the ROM that tells the PowerBook not to use the FPU, in which case the obvious upgrade would be to replace the ROM with one from a PowerBook 550c or a Sonnet upgrade card. If you have either of those, I’m sure [quarterturn] would like to have a word with you.

LIDAR! We all know what the coolest use of LIDAR is, but it’s also useful for robots, drones, and other autonomous thingamadoos. Here’s a Kickstarter for a LIDAR module, 40 meter range, 360 degree range, 500 samples per second, and UART/USB connections.

[Bill] is trying to start a Makerspace in Fort Lauderdale. Here’s the indiegogo campaign.

We launched the 2016 Hackaday Prize this week. Why should you enter? Because last year, it seemed everyone who entered early won something. There’s $300,000 worth of prizes on the line. Need an idea? [Dave Darko] has just the thing for you. It’s the Hackaday Prize Buzzword Generator, the perfect thing for spitballing a few ideas and seeing what sticks.

stupid-ideas

Petite Package Provides Powerful Robot

The Robot Operating System (ROS) is typically associated with big robots but [Grassjelly] decided to prove differently by creating Linorobot. This small, differential drive robot is similar in appearance to many small Arduino based robots often used for line following. Linorobot packs a lot more computing power with a Teensy 3.1 connected to a Radxa Rock Pro. The Teensy handles the motors, reading their encoders, and acquisition of IMU data.

The Radxa, new to us here at Hackaday, is a single board computer based on the quad-core ARM Cortex-A9 1.6 GHz CPU. It may not have been seen on our pages but if you’re at Hackaday Belgrade you can attend a session on building a cluster using it. The ability to run Linux is key to using ROS, which is an open source system for controlling robots. With the Radxa running ROS it interfaces directly to the Neato XV-11 Lidar’s dedicated controller board.

The Linorobot packs into a small robot the capabilities usually seen in much larger and expensive robots such as the Turtlebot 2. With this diminutive robot hackers can learn about doing SLAM (Simultaneous Localization and Mapping) and autonomous navigation, plus the other capabilities of ROS.

[Grassjelly] has a tutorial on building the robot which is also a good introduce to ROS. He provides the software as open source. It’s an impressive project which provides a small, comparatively affordable robot for learning and working with ROS. A video of Linorobot SLAMing and navigating [Grassjelly’s] lab is after the break.

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How to Use Lidar with the Raspberry Pi

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.

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Neato Botvac LiDAR Repair Includes Juicy Pics and a Tool Hack

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.

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Police LiDAR Tear Down

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.

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How To Make Hardware, With Examples And An Electric Pickle

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.

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