Subject:
|
Re: !!! Laser attachments for Mindstorms !!!
|
Newsgroups:
|
lugnet.robotics
|
Date:
|
Fri, 8 Oct 1999 18:16:38 GMT
|
Viewed:
|
737 times
|
| |
|
|
In lugnet.robotics, Richard Sutherland writes:
> In lugnet.robotics, Josh Yeager writes:
> > Hi all,
> > I am selling laser modules for Mindstorms. [SNIP]
>
> My initial thought was "Why?", but of course the next couple of posts
> displayed the creative energy of this group and contained several good answers
> to my question.
>
> For range finding using the laser wouldn't monitoring the intensity of the
> return be a fair indicator? Or perhaps pulsing the signal and counting not the
> time, but the number of pulses that exceed some threshold of intensity?
Rangefinding can be done without much of this hassle. I developed an
application a few years ago to "showcase" a product for the optoelectric
company for which I worked. The product was a "position sensitive diode", aka
a photodiode with two anode connections. Light that strikes the photodiode
generated current, and that current flow ratiometrically out of the two anodes
based on where on the chip the light struck. I had an LED (a laser would have
worked also) positioned at an angle a little ways away from the PSD. With a
little bit of optics (a few cheap lenses) I was able to get it so that the
place the light struck the PSD depended on the distance from the LED to the
surface.
surface
------------
/\
/ \
/ \
/ \
LED PSD
It worked beautifully. I did have to pulse the LED, but that was to eliminate
background light from the calculations. It was all run by a microcontroller
far less advanced that the RCX.
The PSD is marketed as (I think)[1] OSM510 by the company, Optek Technology.
My whole project has been written up by them and published as an application
note, so I haven't given out any company secrets. :-) I'm not into Mindstorms
[2] but I think that this would make a great Mindstorms project.
Thanks,
Naji
[1] The product number changed after I finished my design, before the product
made it to the market. I think this is the final one.
[2] I do this stuff at work. I prefer to keep my Lego strictly plastic. :-)
> Aside from that, it would be fun to design a robot to track a moving object
> and project the laser light onto it. By having the RCX remember the initial
> light value from a well shielded directional light sensor, it could follow
> anything that came in front of the light sensor and disturbed that value. If
> you used two light sensors, or the differential light sensors out there, it
> would be even easier.
>
> Laser tag sounds like another interesting alternative. It would be difficult
> to 'score' a hit on another robot due to the narrow beam. Is anyone good
> enough at optics to elaborate on how the beam could be diffused into more of a
> cone shape?
|
|
Message is in Reply To:
 | | Re: !!! Laser attachments for Mindstorms !!!
|
| (...) My initial thought was "Why?", but of course the next couple of posts displayed the creative energy of this group and contained several good answers to my question. For range finding using the laser wouldn't monitoring the intensity of the (...) (25 years ago, 8-Oct-99, to lugnet.robotics)
|
26 Messages in This Thread:
 
 
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
