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New Sensor Suggestion/Request. — Parallax Forums

New Sensor Suggestion/Request.

lboucherlboucher Posts: 139
edited 2007-01-17 22:43 in Robotics
Hi this question is really for anyone from paralax.

Is there any plans to offer a small laser rangefinder, if at all possible. It would be a great upgrade from the ping. Just a small simple single laser to return a distance, that can be mounted on a servo just like the ping. This would be a great way to get around problems with the ping. Especially the issue that when you are trying to get a distance with the ping to an object that is set at an angle to the ping sensor you always get longer returns. A laser would take care of this. Would love a miniature Sick Laser Range Finder but i think that probably a little much.

Has anyone else been able to integrate a laser rangefinder onto the Boe and what did you use.

Thanks All

Comments

  • Monkey4saleMonkey4sale Posts: 28
    edited 2007-01-12 17:53
    I havent tried and have no idea on how it would work but my geuss is that you would have your laser pointer and some sort of light detection. Then shoot the laser for a split second or so and wait for the result, measure how long it takes and you have you distance after some conversion.

    Im pretty sure construction companies have some handheld version of this to measure the height of buildings but im not sure.
  • allanlane5allanlane5 Posts: 3,815
    edited 2007-01-12 19:33
    It's possible a laser range-finder would have a worse off-bore reaction than the 'ping' does. In other words, if the laser pointer didn't hit the target squarely and 'bounce' back exactly, you'd get no return at all.

    Also, a laser range-finder operates at the speed of light (as I recall). That's like 12" per nanosecond (rule of thumb thanks to Grace Hopper.). So in one micro-second it would go 1000 feet. You'd need an on-module processor to read the distance, then send some signal the BS2 could use, because the BS2 doesn't have the timing resolution to read that signal.
  • allanlane5allanlane5 Posts: 3,815
    edited 2007-01-12 19:34
    One other idea would be to add a laser-diode TO the 'ping' sensor, so you can see the center point of what it's aiming at.
  • John R.John R. Posts: 1,376
    edited 2007-01-12 19:55
    I don't know that seeing the center point would be all that usefull, as the Ping[noparse]:)[/noparse])) is sending out a "cone" for sensing, and receiving the echos back. While it would show the general direction the sensor is pointing, it won't show what surfaces are reflecing (or obsorbing) sound, and what echos are being processed. Because of the nature of how the Ping[noparse]:)[/noparse])) works, you can probably get a reasonable idea of what's happening by just looking at what direction the sensor is pointed.

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    John R.

    8 + 8 = 10
  • lboucherlboucher Posts: 139
    edited 2007-01-12 23:28
    ya there will be some additional processing needed to get the timing right, But i work in the robotics field. Lasers systems definitly do not have the problem with surfaces at an angle, They are actually very precise. Check out the sicks http://www.sick.com/gus/products/product_catalogs/en.html.

    I just don't where to look to find a cheap single laser rangefinder that could be compatible.

    They have laser rangefinders in gun scopes, a very low end model like that should work, I just don't know how to interface it.
  • lboucherlboucher Posts: 139
    edited 2007-01-12 23:30
    IBEO also has an amazing sensor

    http://www.ibeo-as.com/english/technology.asp
  • ZootZoot Posts: 2,227
    edited 2007-01-13 00:22
    Not sure what "inexpensive" is as laser scanners do not seem to be a cheap item, but this is a very reasonable price given the current cost of these sensors.

    For an article describing use:
    acroname.com/robotics/info/articles/laser/laser.html

    To buy:
    acroname.com/robotics/parts/R283-HOKUYO-LASER1.html

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  • kelvin jameskelvin james Posts: 531
    edited 2007-01-13 06:23
    At 50 grand for their cheapest dev kit, the IBEO scanners better have something going for them.

    kelvin
  • lboucherlboucher Posts: 139
    edited 2007-01-13 19:51
    what does a laser rangefinder for a gun sight cost?? and yes the IBEO does some really cool stuff, got to see it in action back at Virginia Tech. And they don't sell so many so there prices are high, very few companies are taking on autonomous ground vehicles
  • Monkey4saleMonkey4sale Posts: 28
    edited 2007-01-14 03:14
    lol, was i actually right about the laser thing? i feel smart

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  • WarrlokWarrlok Posts: 77
    edited 2007-01-16 07:13
    i thought about this awhile back and got as far as maybe using two lasers spaced apart one fixed and have the other converge and then u could measure the angle and get the distance and then i thought i can replace one of the lasers with my camera just need a crosshair (digital or real) i would have to line this up manually ,,, and now i,m thinking if i use two cameras maybe i can use software too line up the images and get the merge angle that my bs2 can use, (hmmm the pan servo position might be accurate enough with a centering routine at start up) does this sound feasible .probly have to gear the pan servo down because i will only need a few degrees of movement but that will make it more accurate well hope it helps

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  • GadgetmanGadgetman Posts: 2,436
    edited 2007-01-16 09:48
    Yes, you could send a laser, then measure the angle, but...

    If you place the laser and the receiver close together you can get by with a small receiver, but will get lousy resolution and horrible accuracy over distance.

    If you place the laser and receiver well apart you'll need a larger-surfaced receiver, but will get better accuracy over distance.

    Something like these might be useful as receivers:
    http://www.sales.hamamatsu.com/en/products/solid-state-division/image-sensors/photodiode-array-with-amplifier/s8865-128.php

    Edit:

    Found a bunch of them at Mouser:

    http://www.mouser.com/search/Refine.aspx?Msb=0&Mkw=linear&Ntk=Mouser_Wildcards&Ne=1491393+1447464&Ntx=mode+matchall&Ns=P_SField&Ntt=*linear*&N=1323038%201491393

    Some of them are even affordable...

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    Post Edited (Gadgetman) : 1/16/2007 9:54:07 AM GMT
  • HenrymouHenrymou Posts: 128
    edited 2007-01-17 05:01
    I HAVE DA ANSWER!!!!!!!!!!!!! yeah.gif don't buy one! I saw on this oone website, a laser range finder, but it was $2500! RIP OFF!!!!!!!!!'
    sry pal
    -peace Henry
  • GadgetmanGadgetman Posts: 2,436
    edited 2007-01-17 22:43
    Laser rangefinders ARE expensive.

    The cheap ones(less than $150 or so) models are all ultrasonics, and the laser beam is just an aiming tool.
    A $2500 one may sound a bit expensive, but what kind of acuracy does it have?
    And what kind of casing?
    (An IP67, dust and waterproof enclosure is expensive, and if you want shock-absorption, that'll also cost you)
    Does it interface with other types of equipment?
    (Some can be mounted on a tripod, then set to rotate and tilt up and down, to scan the entire area, so that you can download a complete 3D map from it later)

    Some of the guys at the office walk around with $5000 GPS units.
    And they wanted an even more expensive model...

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