Author Topic: Hardware Gurus: Lidar, Laser Ranging, Sick... why expensive?  (Read 4668 times)

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Offline jumbaliTopic starter

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Hardware Gurus: Lidar, Laser Ranging, Sick... why expensive?
« on: February 21, 2008, 04:36:51 PM »
Why is Lidar so expensive? More importantly, how could the cost come down on laser rangers so hobbiest could have access to them?

From what I understand, the mechanicals are pretty straightforward: you've got a laser, optics both for shooting out the laser and optics as it comes back in, the photodetection unit, and processing to do timing of the laser flight.

Which part of this makes it so expensive? I can get a laser pen on Ebay, I can find optics at a variety of vendors, and a general purpose microcontroller is a few bucks. Is calibration of each unit expensive? Does it take a special purpose, more expensive laser?

Hardware gurus -- curious if you have any insight...

Offline paulstreats

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Re: Hardware Gurus: Lidar, Laser Ranging, Sick... why expensive?
« Reply #1 on: February 21, 2008, 05:25:30 PM »
How many mcu's can realistically run at a speed to calculate light speed?

Offline sdk32285

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Re: Hardware Gurus: Lidar, Laser Ranging, Sick... why expensive?
« Reply #2 on: February 21, 2008, 07:22:41 PM »
Hi
One of the items you missed was the mirror.
The optics, MCU, and laser are tuned and of a higher quality than what you buy on ebay/discount store.
The mirror timing is very reliable.

Their proprietary algorithms are usually better than home-brew and they can charge a lot for them.

Commercial sensors are also better at not getting dazzled when exposed to direct light sources.

The amount of testing and reliability testing needed is high, especially for safety systems (ie. SICK)

They need to make a profit.

etc...
Robots for Roboticists Blog - http://robotsforroboticists.com/

Offline Centaur

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Re: Hardware Gurus: Lidar, Laser Ranging, Sick... why expensive?
« Reply #3 on: March 01, 2008, 03:07:17 PM »
I don't know specifics on the laser range finders, but I do know in general:

Prices will come down because of economy of scale, but that's not going to happen for a long time (until major auto manufacturers are producing autonomous cars).

Prices will also come down with manufacturer cost reduction activities, but once again, this takes time.

Don't forget to use these sensors you need a ton of processing power, The DARPA vehicles that use these sensors have their trunks full of processing power with codes upwards of 120k lines (and the specific one I'm thinking of was for the desert competition, not the much more complicated city competition).  (although they use many more sensors besides just the laser range finders).

If you already knew this I appologize, I'm new to the community so I'm not familiar with the stuff the average member knows.
Any intelligent fool can make things bigger, more complex, and more violent.  It takes a touch of genius - and a lot of courage - to move in the opposite direction.  ~E.F. Schumacker

Offline guncha

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Re: Hardware Gurus: Lidar, Laser Ranging, Sick... why expensive?
« Reply #4 on: July 11, 2009, 07:46:00 AM »
Actually, laser ranging isn't that expensive anymore. Guy's at MIT made laser rangefinder for under 500$.
http://www.media.mit.edu/resenv/pubs/theses/Josh.pdf

And that was 10 years ago, the time of Win98 and PentiumII! Today you can get better parts for less, big cheers going to optical communications industry and maybe even people who make consumer DVD writers and stuff.

I think that an enterprising soul could make a hobby grade ranger for ~200$, but for some reason I haven't heard of anybody who has done that.

Offline guru

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Re: Hardware Gurus: Lidar, Laser Ranging, Sick... why expensive?
« Reply #5 on: July 11, 2009, 03:20:43 PM »
There is no MCU that can process at the speed of light of course...LIDAR does not measure the speed of light at all.  Maybe I am wrong, I looked up LIDAR devices a while ago but the details are fuzzy now. It outputs an amplitude modulated signal and detects the phase difference between the bounced signal and the sent signal. This is all in the optics. The MCU then has a much simpler task of measuring the phase difference signal and computing the distance based on the wavelength of the modulated signal.

I remember that infrared or near infrared is used as most objects are opaque to infrared and the infrared signal bounces back along the incident angle directly back to the transmitter. A motorized unit is then used to scan the area taking raster measurements.

C

Offline 4by4

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Re: Hardware Gurus: Lidar, Laser Ranging, Sick... why expensive?
« Reply #6 on: July 12, 2009, 11:04:24 AM »
The rangefinders such as the Bushnell product line measure range using laser light and only cost around $200. Some use pulse radar techniques (time of flight) others use CW radar techniques (phase difference measurement).

 


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