laser range finder
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Posts: 46,084
This is my first post so keep that in mind.
I was wondering if anyone had any ideas on how to turn one of those
cheap laser pointers you can buy anywhere now days into a laser range
finder for a robotic project? I thought using a cds cell of some
sort and using pulsout to power the laser diode but im not sure how
to set it up and figure the delay to calculate distance.
Thanks in advance
Jay
I was wondering if anyone had any ideas on how to turn one of those
cheap laser pointers you can buy anywhere now days into a laser range
finder for a robotic project? I thought using a cds cell of some
sort and using pulsout to power the laser diode but im not sure how
to set it up and figure the delay to calculate distance.
Thanks in advance
Jay
Comments
You can get a very good high quality range finder from
http://www.acroname.com The devantech srf04 for $25 it has a range of 3cm to
3 meters. The GPD sharp series of range detectors also are nice, they have a
shorter ranger, more like 6 feet as I recall.
I have written an article on the Devantech for Nuts & Volts, but it wont be
published for a few months. I have used the devantech ranger on a basic
stamp ii, and found it to be a reliable sensor.
-kerry
At 04:31 PM 11/21/01 -0000, you wrote:
>This is my first post so keep that in mind.
>
>I was wondering if anyone had any ideas on how to turn one of those
>cheap laser pointers you can buy anywhere now days into a laser range
>finder for a robotic project? I thought using a cds cell of some
>sort and using pulsout to power the laser diode but im not sure how
>to set it up and figure the delay to calculate distance.
>
>Thanks in advance
>
>Jay
>
>
>To UNSUBSCRIBE, just send mail to:
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>
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>
>
>
Sincerely
Kerry
Admin@M...
WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
Kerry Barlow
p.o. box 21
kirkwood ny
13795
607-775-1132
For that matter at 299,792,458 m s-1 (in a vacuum) the laser bounce from
150meters away would only take about 1 microsecond.
Now if you were to upgrade the laser to one able to bounce off the
moon.........
Original Message
From: <j_bierstedt@h...>
> This is my first post so keep that in mind.
>
> I was wondering if anyone had any ideas on how to turn one of those
> cheap laser pointers you can buy anywhere now days into a laser range
> finder for a robotic project? I thought using a cds cell of some
> sort and using pulsout to power the laser diode but im not sure how
> to set it up and figure the delay to calculate distance.
>
> Thanks in advance
>
> Jay
Original Message
From: "Kerry Barlow" <admin@m...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, November 21, 2001 9:23 AM
Subject: Re: [noparse][[/noparse]basicstamps] laser range finder
> Jay: I dont know as it is worth the bother for you to use a laser pointer.
> You can get a very good high quality range finder from
> http://www.acroname.com The devantech srf04 for $25 it has a range of 3cm
to
> 3 meters. The GPD sharp series of range detectors also are nice, they have
a
> shorter ranger, more like 6 feet as I recall.
> I have written an article on the Devantech for Nuts & Volts, but it wont
be
> published for a few months. I have used the devantech ranger on a basic
> stamp ii, and found it to be a reliable sensor.
> -kerry
>
> At 04:31 PM 11/21/01 -0000, you wrote:
> >This is my first post so keep that in mind.
> >
> >I was wondering if anyone had any ideas on how to turn one of those
> >cheap laser pointers you can buy anywhere now days into a laser range
> >finder for a robotic project? I thought using a cds cell of some
> >sort and using pulsout to power the laser diode but im not sure how
> >to set it up and figure the delay to calculate distance.
> >
> >Thanks in advance
> >
> >Jay
> >
> >
> >To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> >from the same email address that you subscribed. Text in the Subject and
> Body of the message will be ignored.
> >
> >
> >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> >
> >
> >
>
>
> Sincerely
> Kerry
> Admin@M...
> WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
> Kerry Barlow
> p.o. box 21
> kirkwood ny
> 13795
> 607-775-1132
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
Finding at http://www.seattlerobotics.org/encoder/200110/vision.htm
gord u.
j_bierstedt@h... wrote:
>
> This is my first post so keep that in mind.
>
> I was wondering if anyone had any ideas on how to turn one of those
> cheap laser pointers you can buy anywhere now days into a laser range
> finder for a robotic project? I thought using a cds cell of some
> sort and using pulsout to power the laser diode but im not sure how
> to set it up and figure the delay to calculate distance.
>
> Thanks in advance
>
> Jay
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
car in front. Does anyone know if wind noise at highway speeds would
interfere with an ultrasonic sensor? If so, how cheap of a laser
rangefinder can be found?
> Date: Wed, 21 Nov 2001 12:23:13 -0500
> From: Kerry Barlow <admin@m...>
> Subject: Re: laser range finder
>
> Jay: I dont know as it is worth the bother for you to use a laser pointer.
> You can get a very good high quality range finder from
> http://www.acroname.com The devantech srf04 for $25 it has a range of 3cm
to
> 3 meters. The GPD sharp series of range detectors also are nice, they have
a
> shorter ranger, more like 6 feet as I recall.
> I have written an article on the Devantech for Nuts & Volts, but it wont
be
> published for a few months. I have used the devantech ranger on a basic
> stamp ii, and found it to be a reliable sensor.
> -kerry
>
>car in front. Does anyone know if wind noise at highway speeds would
>interfere with an ultrasonic sensor? If so, how cheap of a laser
>rangefinder can be found?
I was also thinking of a working on a laser rangefinder -- or laser speed
detector -- when I get done with the dozen or so projects I am already
struggling to complete. <G>
I believe one of the key components is a "beam splitter". It's a device
that reflects some of the light and passes the rest. The time difference
between the local reflected light and the remote reflected light gives you
distance.
Two more issues:
#1. You need to limit you laser power to 5mw so you don't blind anyone.
#2. I assume that you would have to use a optical magnifying lens in front
of your photodiode in order to detect a small spot at distance.
Jay
> >I was thinking of using a range finder on a vehicle to show distance to the
> >car in front. Does anyone know if wind noise at highway speeds would
> >interfere with an ultrasonic sensor? If so, how cheap of a laser
> >rangefinder can be found?
>
>I was also thinking of a working on a laser rangefinder -- or laser speed
>detector -- when I get done with the dozen or so projects I am already
>struggling to complete. <G>
>
>I believe one of the key components is a "beam splitter". It's a device
>that reflects some of the light and passes the rest. The time difference
>between the local reflected light and the remote reflected light gives you
>distance.
>
>Two more issues:
>
>#1. You need to limit you laser power to 5mw so you don't blind anyone.
Although it is unlikely the beam will be applied to anyone's eye for long
enough to do damage, a 5mw (class IIIa) laser *IS* capable of doing damage
for exposures of about 0.25 second or more. I'd avoid use of class IIIa
lasers. Class IIIa includes many (maybe most) laser pointers.
Jim H
>enough to do damage, a 5mw (class IIIa) laser *IS* capable of doing damage
>for exposures of about 0.25 second or more. I'd avoid use of class IIIa
>lasers. Class IIIa includes many (maybe most) laser pointers.
Does anyone know what kind of lasers the police use in their laser speed
detectors?
Jay
Original Message
From: Jay Hanson [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=9GPsYH-2mcazatmxBNsrSQnGnZWoipHJoNsC8uv3fi8duLHU698yFUZNmAp6Cg0G49o]j@q...[/url
Sent: 22 November 2001 19:29
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] Re: laser range finder
>Although it is unlikely the beam will be applied to anyone's eye for long
>enough to do damage, a 5mw (class IIIa) laser *IS* capable of doing damage
>for exposures of about 0.25 second or more. I'd avoid use of class IIIa
>lasers. Class IIIa includes many (maybe most) laser pointers.
Does anyone know what kind of lasers the police use in their laser speed
detectors?
Jay
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> >Although it is unlikely the beam will be applied to anyone's eye for long
> >enough to do damage, a 5mw (class IIIa) laser *IS* capable of doing damage
> >for exposures of about 0.25 second or more. I'd avoid use of class IIIa
> >lasers. Class IIIa includes many (maybe most) laser pointers.
>
>Does anyone know what kind of lasers the police use in their laser speed
>detectors?
Class I, usually infrared at 904 nm wavelength.
Jim H
>>detectors?
>
>Class I, usually infrared at 904 nm wavelength.
I suspect they use a fairly wide beam instead of a spot like a laser
pointer. True?
Jay
> >>Does anyone know what kind of lasers the police use in their laser speed
> >>detectors?
> >
> >Class I, usually infrared at 904 nm wavelength.
>
>I suspect they use a fairly wide beam instead of a spot like a laser
>pointer. True?
No, they mostly use a narrow beam.
Jim H
>>pointer. True?
>
>No, they mostly use a narrow beam.
So eye damage is eliminated with a very short, intermittent pulse? In other
words, the eye cools between pulses?
Jay
Jim is correct about Class IIIa eye damage. We switched to green diode
lasers for a medical eye tracking application, due to 1/35 lesser power
requirements for same perceived brightness as a 532 nm red diode. As
they say in the laser industry: "Never stare into the laser beam with
your remaining good eye."
Dennis
Original Message
From: Jim Higgins [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=YIrGaX2UVAl8RsN4hRYeH51suHuRnQy4xdq303wKLbOZsMi8Spvu1y3KoxwtAD9PxiyeGl5hioa-4rqb]HigginsJ@s...[/url
Sent: Thursday, November 22, 2001 10:23 AM
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] Re: laser range finder
At 11:46 11/22/01, Jay Hanson wrote:
> >I was thinking of using a range finder on a vehicle to show distance
to the
> >car in front. Does anyone know if wind noise at highway speeds would
> >interfere with an ultrasonic sensor? If so, how cheap of a laser
> >rangefinder can be found?
>
>I was also thinking of a working on a laser rangefinder -- or laser
speed
>detector -- when I get done with the dozen or so projects I am already
>struggling to complete. <G>
>
>I believe one of the key components is a "beam splitter". It's a
device
>that reflects some of the light and passes the rest. The time
difference
>between the local reflected light and the remote reflected light gives
you
>distance.
>
>Two more issues:
>
>#1. You need to limit you laser power to 5mw so you don't blind anyone.
Although it is unlikely the beam will be applied to anyone's eye for
long
enough to do damage, a 5mw (class IIIa) laser *IS* capable of doing
damage
for exposures of about 0.25 second or more. I'd avoid use of class IIIa
lasers. Class IIIa includes many (maybe most) laser pointers.
Jim H
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> >>I suspect they use a fairly wide beam instead of a spot like a laser
> >>pointer. True?
> >
> >No, they mostly use a narrow beam.
>
>So eye damage is eliminated with a very short, intermittent pulse? In other
>words, the eye cools between pulses?
No, the lasers used in police radar are Class I, 39 microwatts (if I
remember correctly) maximum power output. These are harmless.
Jim H