I'm researching a project, and am having difficulty finding one major
component required. I need to be able to find distances between
20-100ft or so with maybe 1ft accuracy. Is there anything out there
that comes anything close to this? I've seen laser range finder
products available, but I haven't found any sensor modules. I suppose
getting a complete system and pulling it apart would be an option, but
I thought I'd ask the list.
I am not so sure what objects are you detecting and
what is the requirement. The property of the object
and the background can affect the design by a lot.
What do you mean by "20-100ft with 1ft accuracy"?
Do you mean that you want to detect objects between
20-100ft and maybe 19 to 101ft are okay? Or do you
mean that you want to detect an object in adjustable
x +/-1 foot with 20<=x<=100? The 2nd explanation may
be harder to achieve.
There are some optics sensors called convergent beam
sensors or fixed focus background suppression sensors
which only detect certain ranges. They have "cross eyes"
between the emitter and receiver light path so that only
the crossed region will be detected. Most convergent beam
sensors use a lens system that focuses the emitted light
to an exact point in front of the sensor, and focuses the
receiver element at the same point. This design produces
a small, intense, and well-defined sensing area at a fixed
distance from the sensor lens.
However normally the sensing distance is much lower. A
laser emitter based convergent beam sensor might be possible
to achieve the sensing distance.
>I need to be able to find distances between
>20-100ft or so with maybe 1ft accuracy.
I would have thought that an ultrasonic ranger - the sort of thing real
Estate Agents (Realtors for our American friends) would use to measure room
sizes, would fit the bill.
Thanks for all the responces, to clarify I would like to be able to
get distance anywhere between about 20-100ft (more is better) with
measurements being accurate to within about 1ft as in Chen's second
description. I would like to be able to detect any opaque object, but
the material could be restricted to pretty much anything if it would
make the range finding easier.
I keep finding laser measurement tools that fall into two basic
categories, some don't quite have the range I'm looking for, but are
inexpensive ($30 USD), and others do way more than I need and are very
expensive ($300+) see below for links. I'll keep looking for one in
the middle, or a sensor module that I can just drop into my project.
Check out the Leica Disto. Not cheap, but uses a laser to do
rangefinding. Also automatically can do Pythagorean theorum to figure
out the actual length of an object that is only facing you at an
angle. It's really amazing!
Josh
--
A common mistake that people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools.
-Douglas Adams
On 9/30/05, Jake Brownson <spam_OUTjbrownsonTakeThisOuTgmail.com> wrote:
> I'm researching a project, and am having difficulty finding one major
> component required. I need to be able to find distances between
> 20-100ft or so with maybe 1ft accuracy. Is there anything out there
> that comes anything close to this? I've seen laser range finder
> products available, but I haven't found any sensor modules. I suppose
> getting a complete system and pulling it apart would be an option, but
> I thought I'd ask the list.
On Fri, 30 Sep 2005 09:11:46 +0100, Alan B. Pearce wrote:
> >I need to be able to find distances between
> >20-100ft or so with maybe 1ft accuracy.
>
> I would have thought that an ultrasonic ranger - the sort of thing real
> Estate Agents (Realtors for our American friends) would use to measure room
> sizes, would fit the bill.
Not at that range, I'm afraid - the best ones run out at about 20m (60') or thereabouts. You'd need a laser
for 100'.
On Fri, 2005-09-30 at 00:18 -0700, Jake Brownson wrote:
> I'm researching a project, and am having difficulty finding one major
> component required. I need to be able to find distances between
> 20-100ft or so with maybe 1ft accuracy. Is there anything out there
> that comes anything close to this? I've seen laser range finder
> products available, but I haven't found any sensor modules. I suppose
> getting a complete system and pulling it apart would be an option, but
> I thought I'd ask the list.
While 100ft might be nearing the limits of common hardware, ultrasonic
ranging can do it. You might have to design a better receiver then
stock, but it's certainly doable. TTYL
It seems that the kinds of range finding devices used in golf and
hunting fit pretty well, but are still just a bit on the spendy side,
and would require some reverse engineering to use. I found the
wonderful site which I'm sure most of you are already aware of: http://www.globalspec.com and there are a couple of "time of flight"
sensors (see below) there that look promising and seem to be what's
used in the golf/hunting distance finders, I've contacted the
companies to see what they can do for us.
> On Fri, 2005-09-30 at 00:18 -0700, Jake Brownson wrote:
> > I'm researching a project, and am having difficulty finding one major
> > component required. I need to be able to find distances between
> > 20-100ft or so with maybe 1ft accuracy. Is there anything out there
> > that comes anything close to this? I've seen laser range finder
> > products available, but I haven't found any sensor modules. I suppose
> > getting a complete system and pulling it apart would be an option, but
> > I thought I'd ask the list.
>
> While 100ft might be nearing the limits of common hardware, ultrasonic
> ranging can do it. You might have to design a better receiver then
> stock, but it's certainly doable. TTYL
>
>
> -----------------------------
> Herbert's PIC Stuff:
> http://repatch.dyndns.org:8383/pic_stuff/
>
gmail.com> wrote:
