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[DPRG]Wall-E -> 1GHZ computers laser rangefinding

Subject: [DPRG]Wall-E -> 1GHZ computers laser rangefinding
From: jdrumm9015 at aol.com jdrumm9015 at aol.com
Date: Sun Jul 6 09:22:33 CDT 2008

Ray,
  Wow, time of flight of a photon, that is pretty fast electronics.  Why not get a fancier laser that really emits in one wavelength and one phase and fire it continiously.  Look for the phase shift as the indication of distance rather then trying to time the flight of a photon.  The tradeoff is you will need a fancier laser that has controlled phase.  This is the idea behind the laser bugs.  They shine a laser on a window and monitor the small movements of the window caused by talking by monitoring the phase shift of the reflected signal.

  Just another high dollar complex project to implement. :)

John Drummond


-----Original Message-----
From: Dean Hall <dwhall256 at gmail.com>
To: dprglist at dprg.org
Sent: Fri, 4 Jul 2008 7:34 pm
Subject: Re: [DPRG]Wall-E -> 1GHZ computers laser rangefinding


Ray, sorry to tell you I am not aware of any commercial-off-the-shelf logic device that operates at 1 GHz (1 picosecond period). 
 
In the realm of programmable logic, the (fastest, I think) Altera Stratix has a 600 MHz core clock. 
 
The closest thing I can think of is a specialized high-speed processor, like the PowerPC 460GT from AMCC. However, I don't see any Timer peripherals, either some serious hacking is in order; or it may not even be possible with this device. 
 
These guys make laser range finders: 
http://www.opti-logic.com/ 
 
And wikipedia says: "Less expensive models around 100$/€ are emerging from Bosch with the DLE 50 or Stanley Works with the TLM 100." 
(from: http://en.wikipedia.org/wiki/Laser_rangefinder) 
 
!!Dean 
 
On Jul 4, 2008, at 18:08 , ray xu wrote: 
 
> Dean: I see why the breadboard is a bad idea. All I need from the > controller is because I need to interface 1gHz counters to it. 
> 
> Ron: I am already done with my sonar project. All I need to do now > is to put it on a board and in a project box. Also, I did some > searching, and the closest thing (http://www.repairfaq.org/sam/lr/) > I came to says that it uses a computer controller. 
> 
> 
> Heres my theory of operation: 
> 
> The controller will be instructed to trigger a laser pulse (650 nm > laser diode), start a timer/counter, wait for the beam to come back > (receiver: OPT101 with concave lens on top of photo-sensitive > area), disable the counter/timer, do some calculations, display > results, and loop. 
> 
> 
> ___________________ 
> Ray Xu 
> rayxu at tx.rr.com 
> DPRG member 
> OOPic group member 
> Seattle Robotics group member 
> My Blog 
> Custom HTML generated signature upon sending 
> 
> -----Original Message----- 
> From: dprglist-bounces at dprg.org [mailto:dprglist-bounces at dprg.org] > On Behalf Of DeltaGraph at aol.com 
> Sent: Friday, July 04, 2008 2:59 PM 
> To: dwhall256 at gmail.com; dprglist at dprg.org 
> Subject: Re: [DPRG]Wall-E -> 1GHZ computers laser rangefinding 
> 
> 
> Dean / Ray 
> 
> 
> Dean,Good point on Ray's project. 
> 
> I guess the question is to find out what you are trying to do, Ray. 
> 
> 
> That is, if you are attempting to measure time of flight of light > you may be talking an advanced project where specialized hardware/ > knowledge might be needed. 
> 
> 
> Reference designs are a good place to start. 
> 
> 
> Yeah, breadboarding in this range would be out. 
> 
> 
> Might suggest playing with sonar first. You will learn a good deal > and sound's propagation rate is 1 millionth the speed of light. > Master that first. Just Me Talking. 
> 
> 
> 
> 
> Ron 
> 
> 
> 
> Gas prices getting you down? Search AOL Autos for fuel-efficient > used cars. 
> 
> No virus found in this incoming message. 
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