CHEAP LIDAR: We were looking for an inexpensive LIDAR (laser ranging) solution for a robotics project we were working on. We could not find one so, using the lidar unit for the XV-11, we developed one: PROTOX2D LIDAR (http://www.affalabs.com/products/protox2d). Its simple to use - via the provided usb cable, simply read Serial output (115200bps, 8N1) the angle and distance values. Angles 0-360 degrees, and distance value are in millimeters(mm). Can be used with many sbc such as raspberry pi, pcduino, pc, mac, etc....any device that can read serial output via usb.

data output: Unit ID, Y Degree (always 0 for ProtoX2D), X Degree, Distance in mm, Quality of Signal, RPM of Laser Assembly, CRNL

EXAMPLE USE from a Linux terminal:

>> screen /dev/ttyUSB0 115200

sample output:
['A1', '0', '276', '239', '1094', '203']
['A1', '0', '277', '239', '1100', '203']
['A1', '0', '278', '240', '1123', '203']
['A1', '0', '279', '240', '1118', '203']
['A1', '0', '308', '302', '734', '203']
['A1', '0', '309', '298', '881', '203']

Views: 20800

Comment by Gary McCray on March 6, 2014 at 1:38pm

Hi Laird,

This is really excellent you have seriously reduced the cost of entry for a laser scanner.

And 6 meters is a great range for one that doesn't require Laser use eye warnings or liability.

And 2 mm accuracy with a 10% reflective surface is really very good.

On your listed set of readings above, I notice a jump from 279 degrees to 308 degrees - why?

Seems like it should just give you a new reading every degree and kind of problematic if it doesn't.

Accuracy and reliability should increase as proximity decreases and for most robotic object acquisition or avoidance applications that is just what you would want.

Bright sunlight is always a problem and it interferes greatly with the $2700.00 Hokuyo I have as well.

The ones that have less problem have all kinds of Laser eye warnings on them.

Does the top central exterior round black element on yours spin or is it stationary?

On the other laser scanners, the external "dome" is stationary and laser transparent, but it looks like yours might actually spin.

One problem with other Laser scanners is that they can be more easily damaged by shock than most people expect.

In this group the first thing people will want to do is stick one on a multicopter (which has every likelihood of making an unplanned sudden encounter with the ground or other equally unyielding object), durability is a very important issue.

Basically, what happens if it falls on the floor?

The Hokuyou is about the same height as yours but 1/2 the width and less than 1/2 the length and weighs 5 ounces less than 1/2 the weight and for use in air vehicles the size and weight is very important, for ground vehicles not as big a deal.

Nonetheless, in spite of any difficulties your price / performance breakthrough certainly makes affordable what until now wasn't.

You might contact 3DR to see if they would like to carry this and also I would suggest possibly Robotshop, Adafruit, Pololu and Trossen.

Best of Luck,

Gary

Comment by Laird Foret on March 6, 2014 at 1:47pm

Gary,

Thanks so much for all your info and comments. So YES the lidar turret spins externally and this can be a problem if it falls facing that way down. We could put a 'roof' on it but the columns supporting it would block several degrees. BUT we could make this alternation trivially. It does not always return 360 distance points per revolution. it may take 3-5 revolutions to get all angles....you get about 90% of the 360 per rev..at its 2.5-3 rps a complete refresh of all data points .5-1.5 seconds. Again, this is NOT a hardened professional LIDAR..just experimental. would be great for an indoor SLAM nav system. 

Comment by Gary McCray on March 6, 2014 at 2:01pm

Hi Laird,

I do think your system has lots of uses.

Simple SLAM is actually a lot less computationally problematic to implement with the more reduced data set from a scanner than it is from the giant 3D point cloud of a full structured light device like the Kinect or Asus Xtion Pro or a 3D TOF camera like the Kinect "v2".

I think this scanner will find lots of interesting applications.

Comment by Jack Crossfire on March 6, 2014 at 2:27pm

It's as heavy as a brick.  The mane reason it's taken 4 years for the XV-11 to finally become popular for hobbyists is the difficulty in getting one without the vacuum cleaner.  Only now can you find a small number on ebay.  We had to bust our balls to get the ebay seller to actually ship it.

Comment by Alejandro Martin Pirola on March 6, 2014 at 3:02pm

Seems like a Neato/Roomba LiDAR in a 3d printed box. Take a look, pretty much the same sensor:

http://www.ebay.com/itm/NEW-NEATO-XV-11-LIDAR-LASER-DISTANCE-SENSOR...

Comment by Laird Foret on March 6, 2014 at 3:24pm

Alejandro, Yes you are correct and we are not at all trying to hide this fact. We used NEW XV-11 lidar units, coupled with a micro controller, motor controller, custom software, other electronics and custom fabricated housing. We simply are putting this out there for people who value their time. We have several hundred hours invested in this seemingly 'simple' project. This works out of the box in seconds.

Comment by Alejandro Martin Pirola on March 6, 2014 at 4:07pm

Laird, please don't get me wrong, I'm glad your team build this LiDAR almost RTF. Actually I was waiting for something like this. XV-11 LiDAR units are great, but requires a lot of work get this things working out properly. Cheers

 

Comment by Alejandro Martin Pirola on March 6, 2014 at 4:27pm

Would be nice get LiDAR data stream and full fill it with IMU data such as pitch and roll + Sonar Range Sensor for Alt. in order to get a full 360 degree x ~45 vertical aperture point cloud, taking advantage of multicopters pitch & roll balancing.

Comment by Gary McCray on March 6, 2014 at 5:32pm

Of course, I should have realized, excellent use of Neato, I think it is great that you guys wen to the trouble to actually turn this remarkably inexpensive commercial product into something we can actually use.

Based on what I have read, I have no doubts at all regarding amount of time invested to get it working right.

From what I have also read, as I recall it is not actually a TOF device, rather an angle offset on cmos imager device and as I recall therefore subject to diminishing resolution and accuracy at greater ranges.

http://www.hizook.com/blog/2009/12/20/ultra-low-cost-laser-rangefin...

However, that isn't really significant to its function and the Neato vacuum cleaner it is used in does itself employ SLAM to map its environment and to establish it's path through it.

A simple single servo operated pitch tilt platform could serve to provide and X / Y / (Z) map or point cloud of the area ahead of you.

This can work well for ground robots, but is definitely heavy and cumbersome for air ones.

Gary

Comment by Aaron Curtis on March 6, 2014 at 5:44pm

How much of the weight is the box? Any chance of dropping a few grams there?

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