Scanse LIDAR update

[Ralph Hipps]

So after much testing and trial I've decided to give up on this thing, too unreliable.

Others like Steve Dillo have reached the same conclusion, and I can see why.

I did have some initial success but the LIDAR eventually hangs and stops responding. Power cycling can recover the unit, but that's not a great solution as it takes several seconds to reboot.

In the interest of science (?) I decided to disassemble the thing to see if there were any reusable components inside (after paying $250 for it) and low and behold there's a perfectly good Garmin LIDAR Lite v3 inside!

I tested that and it seems rock solid so far.

I found it interesting that Scanse would convert the I2C from the Garmin to serial, but perhaps that's better for driving longer wires. They also output a number of other data on the serial stream, of course.

You can see the encoder teeth in the housing in the pictures. Perhaps some enterprising soul could create their own motor control loop for this thing and resurrect them, but replacing the encoder optics might be tricky once you remove the original board.

You can see the motor & slip ring connectors as well.

I have a couple of other ideas for this thing as well, we'll see...

Maybe mount the top portion on a stepper? Then just sweep a smaller area of interest?

https://www.sparkfun.com/products/9238

[Ralph Hipps]

sorry, I should have said 'lo and behold.'      =)

Ralph

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[Sergei Grichine]

I bought a similar LIDAR a while ago, when they just appeared. It was very unreliable, and I learned that it consumes rather high current when pulsing the laser, and thus (a) can interfere with other connected electronics and (b) is itself very demanding to the quality of the power supply. My attempts to tame it by connecting large capacitors failed. I ended up programmatically "fixing" wrong readings, but ultimately it wasn't fun to use. I would guess the Garmin LIDAR is somewhat better, but the high amperage pulses are an essential design feature and must be accounted for. 

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Best Regards,

-- Sergei

[Ralph Hipps]

yes, they recommend a large (680 µF) cap on its power pin to help with that.

I was powering it with a 5 V, 3 A, wall wart last night, so no issues there.    =)

Ralph

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[Chris Albertson]

The best deal for a reliable LIDAR is to buy the Neato vacuum cleaner part on eBay for $30.   The cost is low because this is a mass-produced consumer part, not a specialty robotics item.  

Yes, we tend to think the $300 unit will be better but, mass production brings prices down and the company's fear of warranty re-work keeps the quality up.   Those $30 units work well but still, you want to buy a spare unit or two.   I have several and no problems yet, very reliable.  If they do fail you can buy replacement scan motors and bands.

There are two versions, the older one used a slip ring, the newer version has a wireless data and power path to the spinning platform.  The wireless one has a longer design lifetime.  But even the slip ring version works for years of daily use in a vacuum cleaner but does wear out.  Neato invented the wireless version that lasts practically forever as the slip ring was the usual point of failure.    But most hobby robots will not run for one hour every day as my vacuum cleaner does.   

I disassembled a wireless unit to see how it works.  The data path uses an LED and photosensitive diode to send data down the spin axis.  (It is like fiber optics with no fiber.)  The power is sent via coils.    It is an air-core transformer with the primary on the fixed side and secondary on the spinning platform, low voltage AC power goes across the air gap (as used on wireless phone chargers) and is rectified and regulated on the spinning platform.    What is impressive is that their engineers found a way to do this with cheap parts to keep the cost low.   There is nothing "high tech" inside.  It is all done with 20-year-old common parts.

On Wed, May 5, 2021 at 6:57 AM Ralph Hipps <ralph...@gmail.com> wrote:

So after much testing and trial I've decided to give up on this thing, too unreliable.

Others like Steve Dillo have reached the same conclusion, and I can see why.

I did have some initial success but the LIDAR eventually hangs and stops responding. Power cycling can recover the unit, but that's not a great solution as it takes several seconds to reboot.

In the interest of science (?) I decided to disassemble the thing to see if there were any reusable components inside (after paying $250 for it) and low and behold there's a perfectly good Garmin LIDAR Lite v3 inside!

--

Chris Albertson
Redondo Beach, California

[Ralph Hipps]

Cool stuff!

Ralph

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 -- Nikola Tesla
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[Ralph Hipps]

Minor update, but I've attached a pic showing the internal encoder and the optointerrupter in case someone wants to hack all that.

You can also see the gap in the encoder teeth for the sync pulse.

Also found an adapter hub that appears to match the motor mount spacing on the Scanse, for those that would want to try the stepper motor approach, or any other motor for that matter.

https://www.servocity.com/0-770-0-625-pattern-adapter/

Looked at the Neato LIDARs on ebay, found one for $35 but most are $50. Still pretty cheap all things considered. Too bad they aren't a bit smaller, at least for Reflux, he's not a big bot.

[Steve " 'dillo" Okay]

On Wednesday, May 5, 2021 at 6:57:00 AM UTC-7 Ralph Hipps wrote:

So after much testing and trial I've decided to give up on this thing, too unreliable.

Others like Steve Dillo have reached the same conclusion, and I can see why.

I did have some initial success but the LIDAR eventually hangs and stops responding. Power cycling can recover the unit, but that's not a great solution as it takes several seconds to reboot.

In the interest of science (?) I decided to disassemble the thing to see if there were any reusable components inside (after paying $250 for it) and low and behold there's a perfectly good Garmin LIDAR Lite v3 inside!

Well hey, if there's a LIDAR Lite inside, I might have to get mine out of the drawer its sitting in and crack it open :)

Thanks for the teardown Ralph!

----Steve " 'dillo" Okay

 

[Sergei Grichine]

Is it true that Neato LIDAR won't operate outdoors (Sun infrared) while the Garmin alikes have much more power and can be used in bright sun?

Best Regards, 
-- Sergei Grichine 

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[Brain Higgins]

I use the garmin outdoors in sunlight I tilt it down a couple of degrees 

Garmin makes the Lidar lite for drones

Sent from my iPhone XX

On May 6, 2021, at 10:15 AM, Sergei Grichine <vital...@gmail.com> wrote:



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[Ralph Hipps]

Any time!    =)

Ralph

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[Ralph Hipps]

Sergei,

In general I would say that's true, although I haven't tested my Neato outdoors. I have heard it has little or no range outside.

My other Garmin LIDAR Lite v1 had tremendous range outside, 60+ m.

Ralph

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[Ryan D]

How does the Neato lidar compare to the RP lidar A1? I use the RP Lidar A1 since a lot of other people seem to be using it but this neato lidar could be a cheaper alternative?

[Ralph Hipps]

that I don't know, haven't tested the Neato thoroughly, or the RP A1 at all.

Others may have info on that...

Ralph

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[Brian Higgins]

The RP Lidar A1.  makes an A3 for outdoor 

Sent from my iPhone XX

On May 6, 2021, at 7:43 PM, Ryan D <ryan...@gmail.com> wrote:

How does the Neato lidar compare to the RP lidar A1? I use the RP Lidar A1 since a lot of other people seem to be using it but this neato lidar could be a cheaper alternative?

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[Ryan D]

elaborate?

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[camp .]

> elaborate?

Slamtec RPLIDAR A3 360° Laser Scanner (25 m)

https://www.robotshop.com/en/slamtec-rplidar-a3-360-laser-scanner-25-m.html

 

- Camp

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[Cheuksan Wang]

Does anyone have any experience with the Livox Lidar? It's the same
price as the Slamtec RPLIDAR A3 but it's a 3D Lidar.

https://store.dji.com/product/livox-mid?set_country=US&vid=48991

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[Chris Albertson]

There are several of these 2D scanning LIDARS currently available.  The differences between them are:

1) the power and range of the laser.  The $30 neato can see only to maybe 10 or 12 meters indoors.   This is enough for navigating inside a home or office while the $700 Replidar A3M1 can see out to 40 meters

2) the number of samples per second.  The lower end units to about 1,800.  the A3M1does 16,000 samples per second.  This affects the speed the robot can move and the size of the computer you need to process the data.

3) Level of integration.  The Neato can be bought as a bare unit on eBay for $30.  The Replidar is sold as a plug-and-play system.

All of the under $1,000 LIDARS are considers "low cost".  It is a big jump from there to the professional Velodyne lidars the scan in three dimensions and out to 200 meters and at much higher rates.    

I think the best plan is to match the sensor to your needs.  Look at where your robot operates and how fast it needs to drive.

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[camp .]

> I think the best plan is to match the sensor to your needs.  Look at where your robot operates and how fast it needs to drive.

 

If your goal is to learn ROS I'd suggest you buy the whole Neato robot, either XV or Botvac, and use the ROS1 or ROS2 packages. Much easier than developing a custom base plus it vacuums the floor!  ;-)

 

SV-ROS/intro_to_ros

https://github.com/SV-ROS/intro_to_ros

 

cpeavy2/botvac_node

https://github.com/cpeavy2/botvac_node

 

- Camp

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[Marco Walther]

On 5/11/21 4:58 PM, Cheuksan Wang wrote:
> Does anyone have any experience with the Livox Lidar? It's the same
> price as the Slamtec RPLIDAR A3 but it's a 3D Lidar.
>
> https://store.dji.com/product/livox-mid?set_country=US&vid=48991

The MID-40 is a 38deg circle?! And they seem to try to be smart with the
pattern, so that would probably prevent any rotational setup.

They have a MID-100 on the same page, just without a price.

For $999 you can get a 82deg x 25deg Livox Horizon LiDAR, they have a
picture to cover the 360deg with five of them;-)

They are probably good, but a bit expensive for my hobby taste;-)

-- Marco

[Chris Albertson]

A lot of what you need depends on the robot's speed.   If it is moving slowly at (say) 0.5 meters per second and you want to look ahead 10 seconds then you only need to "see" 5 meters.   Any LIDAR can do that.   But maybe you are building a piza delivery cart that drives at 2 meters per second so now you need 20 meter range.

You need to see ahead to whatever is you path planning horizon.  A 10 second planning horizon is kind of minimal for a self-drive car but maybe over kil for a beer fetching indoor robot.   Engineering is all about trade offs of cost and performance.

The range affects the amount of resolution you need.   The Neato LIDAR has only 1 degree  but at 5 meters this gives 9 cm resolution.  Good enough.   But at 20 meters you need beter resolution to see things like light posts and pedestrians and sure enough the bigger LIDARs have much better agular resolution.

Tesla's Elon Musk has said many times that he is not planning to use LIDAR, I think because of the power and cost needed to see far enough into the distance.  He might be right that video cameras are MUCH cheaper even if you need eight video camera like on a Tesla.     Unlike Google and Uber Tesla has to make afordable cars that people will buy today and can't do that if each car needs to have four $12,000 LIDAR units on the roof.   The Google car has $100K worth of equipment on the roof-racks and a half million dollar computer in the trunk and even work, suck down over 1KW of electric power.    (I Google engineer said some years back that the computer in their car qualifies and the 100th most powerful super computer on Earth.  It was build with custom chips designed just for use in the car.  There is no way thecar could be sold at a reasonable price.

I tend to agree with Musk and think that I can use a stereo depth camera. The camera has very good reolution and can "see" literally forever.  They are also MUCH lower priced than any LIDAR except the Neato.

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[Steve " 'dillo" Okay]

On Wednesday, May 12, 2021 at 11:03:48 AM UTC-7 alberts...@gmail.com wrote:

[...]

Tesla's Elon Musk has said many times that he is not planning to use LIDAR, I think because of the power and cost needed to see far enough into the distance.  He might be right that video cameras are MUCH cheaper even if you need eight video camera like on a Tesla.     Unlike Google and Uber Tesla has to make afordable cars that people will buy today and can't do that if each car needs to have four $12,000 LIDAR units on the roof.   The Google car has $100K worth of equipment on the roof-racks and a half million dollar computer in the trunk and even work, suck down over 1KW of electric power.    (I Google engineer said some years back that the computer in their car qualifies and the 100th most powerful super computer on Earth.  It was build with custom chips designed just for use in the car.  There is no way thecar could be sold at a reasonable price.

I tend to agree with Musk and think that I can use a stereo depth camera. The camera has very good reolution and can "see" literally forever.  They are also MUCH lower priced than any LIDAR except the Neato.

What is the depth sensor though ? It's still some sort of projected beam, right ?

Generating a beam or flash powerful enough where the return is not washed out by ambient lighting still takes a lot of energy, right ?

'dillo

 

[Chris Albertson]

The Intel d400 series Realsense depth camera uses stereo video.  There are two IR cameras.  Yes there is an IR projector that projects random dots all over the scene as this gives the stereo algorithm some easy to find points to match up.   It does not use any kind round trip timing like a lidar.  It works just like human eyeballs do. The IR light is justthere to add some visual texture.

The Tesla cars use plain old video with no projector

Depth cameras don't need the IR projector.  You can make a stereo camera yourself with to cheap webcams and a computer.   Actually you don't need two camera.  You can use just one camera.  You take a frame, move the camera then take a second frame.  This works if nothing in the frame moves.  Doing this continuously, you can extractdepthfrom a single video camera this is on a moving platform with no projector.

On Wed, May 12, 2021 at 5:01 PM Steve " 'dillo" Okay <espre...@gmail.com> wrote:

On Wednesday, May 12, 2021 at 11:03:48 AM UTC-7 alberts...@gmail.com wrote:

[...]

What is the depth sensor though ? It's still some sort of projected beam, right ?

Generating a beam or flash powerful enough where the return is not washed out by ambient lighting still takes a lot of energy, right ?

'dillo

 

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[Sergei Grichine]

Here's a new posting from DFRobot, a LIDAR $70, 50m range outdoors, not a scanner though:

https://www.dfrobot.com/product-2108.html

Best Regards, 
-- Sergei Grichine 

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[Chris Albertson]

Thanks, I always follow up on these notice postings.   IT at first though about mounting this to a scan platform (aka $5 stepper motor)  Then found the spec below

• Single Measurement Time: 0.05~1s

It seems it is really hard to get an eye-safe LIDAR to work at 50M.   The sun is always much brighter than the laser.   Wwhat they do is increase the integration time. At best this LIDAR can only read out 20 points per second.

How do the high-end LIDARs that scan out in 3D to 200 meters work?  Does anyone know?  Do they just use really good and large-diameter optics?  Given their high price point they could.

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[Cheuksan Wang]

Lidars usually use a frequency where the sunlight is mostly absorbed
by water vapor.

https://www.yellowscan-lidar.com/knowledge/why-does-lidar-have-a-specific-wavelength-2/
https://velodynelidar.com/blog/guide-to-lidar-wavelengths/

On Thu, May 13, 2021 at 5:27 PM Chris Albertson

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[Marco Walther]

On 5/13/21 5:27 PM, Chris Albertson wrote:
> Thanks, I always follow up on these notice postings.   IT at first
> though about mounting this to a scan platform (aka $5 stepper motor)
>  Then found the spec below
>

> * Single Measurement Time: 0.05~1s

That thing is essentially a stripped down laser distance meter (I have
this guy and it works ok as far as I can tell;-)
https://smile.amazon.com/dp/B07RZ6YWGC - I would not be surprised when
there is a similar module in there even with the serial interface) So,
not sure, how well that would work for anything other than [semi] static
distance measurements.

-- Marco

>
> It seems it is really hard to get an eye-safe LIDAR to work at 50M.

> The sun is always much brighterthanthe laser.   Wwhat they do is

> alberts...@gmail.com <mailto:alberts...@gmail.com> wrote:
> [...]
>
>
> What is the depth sensor though ? It's still some sort of
> projected beam, right ?
> Generating a beam or flash powerful enough where the return
> is not washed out by ambient lighting still takes a lot of
> energy, right ?
> 'dillo
>
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>
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>
> Chris Albertson
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[Ralph Hipps]

Another update, but it's a minor one, I've tested the Lidar module I removed from the Scanse, and it runs just fine on normal Lidar Lite I2C code, no serial interface required.

They must have done that conversion on the board in the round base.

So it's a standard  Lidar Lite unit, nothing custom about it.

[Dheera Venkatraman]

I had lots of problems with Scanse when I tried them out. If they go
bad, you can pull out the LIDAR-Lite inside it and use that for other
fun things.

But as for repair, personally I'd say ditch it -- slip rings are bad
design. RPLidar is *much* better designed in this regard, as it does
wireless power and wireless communication to the rotating unit. I've
had many running for 2-3 years straight no problems.

The RPLidar a2 and a3 have exposed rotating components like Scanse,
and use triangulation. The RPLidar S1 uses TOF and has a cover on it;
I'd recommend the S1 for outdoor use in sunlight.

____________________
Dheera Venkatraman
http://dheera.net

Ralph Hipps <ralph...@gmail.com> 於 2021年5月5日 週三 上午6:57寫道：

>
> So after much testing and trial I've decided to give up on this thing, too unreliable.
>
> Others like Steve Dillo have reached the same conclusion, and I can see why.
>
> I did have some initial success but the LIDAR eventually hangs and stops responding. Power cycling can recover the unit, but that's not a great solution as it takes several seconds to reboot.
>
> In the interest of science (?) I decided to disassemble the thing to see if there were any reusable components inside (after paying $250 for it) and low and behold there's a perfectly good Garmin LIDAR Lite v3 inside!
>
> I tested that and it seems rock solid so far.
>
> I found it interesting that Scanse would convert the I2C from the Garmin to serial, but perhaps that's better for driving longer wires. They also output a number of other data on the serial stream, of course.
>
> You can see the encoder teeth in the housing in the pictures. Perhaps some enterprising soul could create their own motor control loop for this thing and resurrect them, but replacing the encoder optics might be tricky once you remove the original board.
>
> You can see the motor & slip ring connectors as well.
>
> I have a couple of other ideas for this thing as well, we'll see...
>
> Maybe mount the top portion on a stepper? Then just sweep a smaller area of interest?
>
> https://www.sparkfun.com/products/9238
>
>
>
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[Chris Albertson]

You can save a few bucks.  These LIDAR units are always available on eBay for about $35

here is one example

.ebay.com/itm/194286798185...

There are a couple kinds.  One uses the slip ring and the other the wireless connection.  They run about 1/3rd to 1/2 to price of the LPLidar and are basically identical.   They are designed for indoor use on a vacuum cleaner.   I bought a few of them, each type and they work fine, indoors.

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