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10m-10cm distance measurement with 1cm accuracy at a rate of 50Hz
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Robert Baer
electronics forum Guru


Joined: 25 Mar 2005
Posts: 1159

PostPosted: Fri Mar 25, 2005 7:33 am    Post subject: Re: B&K 290 multimeter alignment? Reply with quote

JOHN D wrote:

Quote:
"Robert Baer" <robertbaer@earthlink.net> wrote in message
news:Igv0e.2610$gI5.2035@newsread1.news.pas.earthlink.net...

JOHN D wrote:

"Robert Baer" <robertbaer@earthlink.net> wrote in message
news:vE90e.1855$gI5.406@newsread1.news.pas.earthlink.net...



Wierd to have two different power levels for resistance...


I think it has to do with providing enough current to turn on solid state
devices. I don't remember where I learned this but supposedly some meters
would falsely show a diode as open cus there wasn't enough current in the
resistance circuit to turn it on..


No, it is not the current; it is the voltage compliance.

There must be sufficent voltage to drive the desired current, for the
diode to conduct in the forward direction.
Note only germanium, silicon and schottky diodes work; LEDs do not.
Hand-held DVMs seem to use about 1mA (some more, some less).
However, one can determine diode types with 10uA or with 100mA.
The 1mA is chosen, so that the voltage drop that is measured, is
recognizable by savvy electronic technicians.
A silicon diode conducts rather well at 1uA, but would have a voltage
drop roughly 200mV less than that expected in "normal" circuits; if you
read 430mV, you might think you had a germanium or a schottky diode
(those would read much lower).
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Robert Baer
electronics forum Guru


Joined: 25 Mar 2005
Posts: 1159

PostPosted: Fri Mar 25, 2005 7:37 am    Post subject: Re: 10m-10cm distance measurement with 1cm accuracy at a rate of 50Hz Reply with quote

Vidar Løkken wrote:

Quote:
Yugo wrote:

Do you know any small size, light weight distance sensor with the
following specs;
* Range : 10cm to 1000cm (10meter )
* Rate : 50 Hz (50 measurements/sec)
* Accuracy : 1cm
* Must operate on any surface (except transparent surfaces like
glass)
* Power requirement : Less than 5W
* Weight : Lighter than 500grams
* Vibrartion sensitivity : Must operate 0-500Hz


No, but I guess they excist. You could use RADAR, simply send out sound,
and see how long time it takes for it to return (knowing sound travels
more or less 300m/s. This would make it dependent on the altitude, but
it'd be easier to make with a microcontroller than light/radio based
RADAR, since light would require really really good timing...



Use of light or radio pulses (as in RADAR) is just as easy as use of
sound pulses; timing is easy.
Been around since the 1940's.
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mlw
electronics forum beginner


Joined: 24 Mar 2005
Posts: 7

PostPosted: Fri Mar 25, 2005 10:33 am    Post subject: Re: 10m-10cm distance measurement with 1cm accuracy at a rate of 50Hz Reply with quote

Robert Baer wrote:

Quote:
Vidar Løkken wrote:

Yugo wrote:

Do you know any small size, light weight distance sensor with the
following specs;
* Range : 10cm to 1000cm (10meter )
* Rate : 50 Hz (50 measurements/sec)
* Accuracy : 1cm
* Must operate on any surface (except transparent surfaces like
glass)
* Power requirement : Less than 5W
* Weight : Lighter than 500grams
* Vibrartion sensitivity : Must operate 0-500Hz


No, but I guess they excist. You could use RADAR, simply send out sound,
and see how long time it takes for it to return (knowing sound travels
more or less 300m/s. This would make it dependent on the altitude, but
it'd be easier to make with a microcontroller than light/radio based
RADAR, since light would require really really good timing...



Use of light or radio pulses (as in RADAR) is just as easy as use of
sound pulses; timing is easy.
Been around since the 1940's.

Ranging radar is very much more difficult than dopler radar. Dopler radar is
fairly easy to do, $100 bucks or so -- hell you can buy dopler radar off
the net to measure your pitching speed.

Ranging radar has to emit a pulse and measure the time delay from transmit
and recieve. With SONAR, this is dist = (340/2)/T (we divide by two because
echo is a two way trip), well in the millisecond range. With RADAR this is
dist = (300000000/2)/T. If you are measuing meters you are in the nano
second range. If you are trying to measure centimeters you are in the pico
second range.

This is not to say it can't be done, but it would be very expensive.
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the Artist Formerly Known
electronics forum beginner


Joined: 25 Mar 2005
Posts: 1

PostPosted: Fri Mar 25, 2005 3:04 pm    Post subject: Re: 10m-10cm distance measurement with 1cm accuracy at a rate of 50Hz Reply with quote

Yugo wrote:
Quote:
Do you know any small size, light weight distance sensor with the following
specs;
* Range : 10cm to 1000cm (10meter )
* Rate : 50 Hz (50 measurements/sec)
* Accuracy : 1cm
* Must operate on any surface (except transparent surfaces like glass)
* Power requirement : Less than 5W
* Weight : Lighter than 500grams
* Vibrartion sensitivity : Must operate 0-500Hz


Check into the SICK laser rangers. Not cheap, though.


--
(Replies: cleanse my address of the Mark of the Beast!)

Teleoperate a roving mobile robot from the web:
http://www.swampgas.com/robotics/rover.html

Coauthor with Dennis Clark of "Building Robot Drive Trains".
Buy several copies today!
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Deep Reset
electronics forum beginner


Joined: 25 Mar 2005
Posts: 2

PostPosted: Fri Mar 25, 2005 3:55 pm    Post subject: Re: 10m-10cm distance measurement with 1cm accuracy at a rate of 50Hz Reply with quote

"Vidar Løkken" <njus@vidarlo.net> wrote in message
news:X_E0e.3993$4c.506280@juliett.dax.net...
Quote:
Yugo wrote:
Do you know any small size, light weight distance sensor with the
following specs;
* Range : 10cm to 1000cm (10meter )
* Rate : 50 Hz (50 measurements/sec)
* Accuracy : 1cm
* Must operate on any surface (except transparent surfaces like
glass)
* Power requirement : Less than 5W
* Weight : Lighter than 500grams
* Vibrartion sensitivity : Must operate 0-500Hz

No, but I guess they excist. You could use RADAR, simply send out sound,
and see how long time it takes for it to return (knowing sound travels
more or less 300m/s. This would make it dependent on the altitude, but
it'd be easier to make with a microcontroller than light/radio based
RADAR, since light would require really really good timing...

You can't meet the 50Hz requirement at maximum range with sound in air, the

best you could get would be about 16Hz.
(assuming 330 metres/second)

Deep.
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Rob
electronics forum beginner


Joined: 25 Mar 2005
Posts: 46

PostPosted: Fri Mar 25, 2005 7:48 pm    Post subject: Re: 10m-10cm distance measurement with 1cm accuracy at a rate of 50Hz Reply with quote

<Yugo> wrote in message
news:4242a351$0$29448$afc38c87@news.optusnet.com.au...
Quote:
Do you know any small size, light weight distance sensor with the
following
specs;
* Range : 10cm to 1000cm (10meter )
* Rate : 50 Hz (50 measurements/sec)
* Accuracy : 1cm
* Must operate on any surface (except transparent surfaces like glass)
* Power requirement : Less than 5W
* Weight : Lighter than 500grams
* Vibrartion sensitivity : Must operate 0-500Hz



Yugo - I don't know if the range or all other constraints are satisfied, but
you may want to have a look at the Sharp ranging modules, IR based IIRC.
Have a look on the Manuco website.
rob
http://www.manuco.com.au/
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Guest






PostPosted: Sat Mar 26, 2005 12:32 am    Post subject: Re: 10m-10cm distance measurement with 1cm accuracy at a rate of 50Hz Reply with quote

Leica has a few hand-held laser distance devices that seem close to
your specs.
http://www.leica-geosystems.com/cpd/en/products/laser_distancemeter

Below is some data about their higher end system. But they also have a
cheaper version that has the similar measurement abilities.
==========The Leica DISTO™ plus is the only device in the world that offers the
highest accuracy, attractive design and wireless data transfer by means
of BLUETOOTH® in one package. Even if you are currently still working
with paper and pencil, integrated BLUETOOTH® technology allows you to
make the change at any time and to record your values electronically.
The data can be transferred on site wireless to a PDA (Pocket PC) or
directly to a laptop and easily used for other purposes.

Range of measurement: 0.2 up to 200 m
(0.7 up to 650ft). Accuracy: ±1.5mm
(0.06in)
==========
Regarding price; I looked at a similar system by another vendor a few
years back and it was around $800 at the time.


Joe Dunfee
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Stef Mientki
electronics forum beginner


Joined: 24 Mar 2005
Posts: 30

PostPosted: Sat Mar 26, 2005 4:54 pm    Post subject: Re: 10m-10cm distance measurement with 1cm accuracy at a rate of 50Hz Reply with quote

Deep Reset wrote:
Quote:
"Vidar Løkken" <njus@vidarlo.net> wrote in message
news:X_E0e.3993$4c.506280@juliett.dax.net...

Yugo wrote:

Do you know any small size, light weight distance sensor with the
following specs;
* Range : 10cm to 1000cm (10meter )
* Rate : 50 Hz (50 measurements/sec)
* Accuracy : 1cm
* Must operate on any surface (except transparent surfaces like
glass)
* Power requirement : Less than 5W
* Weight : Lighter than 500grams
* Vibrartion sensitivity : Must operate 0-500Hz

No, but I guess they excist. You could use RADAR, simply send out sound,
and see how long time it takes for it to return (knowing sound travels
more or less 300m/s. This would make it dependent on the altitude, but
it'd be easier to make with a microcontroller than light/radio based
RADAR, since light would require really really good timing...


You can't meet the 50Hz requirement at maximum range with sound in air, the
best you could get would be about 16Hz.
(assuming 330 metres/second)
No, you can get higher, ...

.... why wait until a pulse is received ?
Ok next thing to do is "modulate" the pulses,
for example,
send a puls
send a second puls 10 msec later
next puls 15 msec later
next puls 12 msec later
By now combining the results of multiple measurements,
you can avoid the ambiguity.

A more diffcult way is to use continuous wave (of course modulated)
ultrasound.

Stef Mientki
Quote:

Deep.

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mlw
electronics forum beginner


Joined: 24 Mar 2005
Posts: 7

PostPosted: Sat Mar 26, 2005 5:29 pm    Post subject: Re: 10m-10cm distance measurement with 1cm accuracy at a rate of 50Hz Reply with quote

Stef Mientki wrote:

Quote:
Deep Reset wrote:
"Vidar Løkken" <njus@vidarlo.net> wrote in message
news:X_E0e.3993$4c.506280@juliett.dax.net...

Yugo wrote:

Do you know any small size, light weight distance sensor with the
following specs;
* Range : 10cm to 1000cm (10meter )
* Rate : 50 Hz (50 measurements/sec)
* Accuracy : 1cm
* Must operate on any surface (except transparent surfaces like
glass)
* Power requirement : Less than 5W
* Weight : Lighter than 500grams
* Vibrartion sensitivity : Must operate 0-500Hz

No, but I guess they excist. You could use RADAR, simply send out sound,
and see how long time it takes for it to return (knowing sound travels
more or less 300m/s. This would make it dependent on the altitude, but
it'd be easier to make with a microcontroller than light/radio based
RADAR, since light would require really really good timing...


You can't meet the 50Hz requirement at maximum range with sound in air,
the best you could get would be about 16Hz.
(assuming 330 metres/second)
No, you can get higher, ...
... why wait until a pulse is received ?
Ok next thing to do is "modulate" the pulses,
for example,
send a puls
send a second puls 10 msec later
next puls 15 msec later
next puls 12 msec later
By now combining the results of multiple measurements,
you can avoid the ambiguity.

How do you differentiate between pulses? What about echos from multiple
surfaces at different distences?
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Jim Douglas
electronics forum addict


Joined: 30 Apr 2005
Posts: 94

PostPosted: Sun Mar 27, 2005 11:58 am    Post subject: Re: Beware of Radio Shack Reply with quote

Now is the guy was buying some cell phone on credit it makes sense otherwise
nope never happened!


"~" <~@1.2> wrote in message news:210320051234152726%~@1.2...
Quote:
give them a fake address.





In article <MeqdnfY6cZ_ZjmrdRVn-hQ@gbronline.com>, Wes Groleau
groleau+news@freeshell.org> wrote:

Gnarlodious wrote:
I bought a small item at Radio Shack several months ago, and the clerk
asked
the man in front of me for his social security number. He began
reciting it
in public but I interrupted him, telling him she didn't need his SS#
and he
should never publicly announce it. A loud argument ensued with the
clerk
bringing out the manager. The manager assured me it was official RS
policy

Every time I try to buy something there, even if I pay cash,
they try to get my address and phone number. I always have
to argue with them. "You don't need my phone number to send
your stupid catalog, and I don't want the catalog anyway."

But they still argue they need it. Eventually I win or
I walk out with my money and no product.
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Paul Nevai
electronics forum beginner


Joined: 28 Mar 2005
Posts: 1

PostPosted: Mon Mar 28, 2005 2:57 pm    Post subject: Re: Beware of Radio Shack Reply with quote

"Jim Douglas" <james.douglas@genesis-software.com> aszonygya:
:> > But they still argue they need it. Eventually I win or
:> > I walk out with my money and no product.

Next time just give my phone and SS#: 1-800-555-5555 and 999-99-9999. I
don't mind it. /Paul
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CBFalconer
electronics forum addict


Joined: 03 May 2005
Posts: 67

PostPosted: Mon Mar 28, 2005 3:38 pm    Post subject: Re: Beware of Radio Shack Reply with quote

Paul Nevai wrote:
Quote:
"Jim Douglas" <james.douglas@genesis-software.com> aszonygya:

But they still argue they need it. Eventually I win or
I walk out with my money and no product.

Next time just give my phone and SS#: 1-800-555-5555 and
999-99-9999. I don't mind it. /Paul

I prefer to use mine; there is more chance they'll put it into
their system: 1-area-555-1212 and 123-54-9876.

--
"If you want to post a followup via groups.google.com, don't use
the broken "Reply" link at the bottom of the article. Click on
"show options" at the top of the article, then click on the
"Reply" at the bottom of the article headers." - Keith Thompson
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D. Kirkpatrick
electronics forum beginner


Joined: 28 Mar 2005
Posts: 1

PostPosted: Mon Mar 28, 2005 4:10 pm    Post subject: Re: Beware of Radio Shack Reply with quote

In article <d29d2h$mrj$1@charm.magnus.acs.ohio-state.edu>,
nevai@math.ohio-state.edu (Paul Nevai) wrote:

Quote:
"Jim Douglas" <james.douglas@genesis-software.com> aszonygya:
:> > But they still argue they need it. Eventually I win or
:> > I walk out with my money and no product.

Next time just give my phone and SS#: 1-800-555-5555 and 999-99-9999. I
don't mind it. /Paul


No commercial entity can demand your SS number by law. If they do,
walk out and report them to the SS administration and the local
state's attorney general's office of consumer protection.

If that is the number on a driver's license you may need to show that
for ID but many states are now replacing the SS number with their own
state-generated number as a matter of privacy. As long as you give
them the special private number on a driver's ID you have fulfilled
the obligations under law for ID purposes.

The number of people who *may* have access to your SS number are very
limited. Those are the SS administration, a bank when opening an
account, the state when getting a driver's license or state ID, a
police officer when seeking ID in the instance of conducting an
investigation (including a traffic stop), The IRS, and en employer
when completing forms for the IRS.

There may be more but the list is limited and I am not an attorney who
can offer more direction.

DMK
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Steve Lidie
electronics forum beginner


Joined: 28 Mar 2005
Posts: 1

PostPosted: Mon Mar 28, 2005 5:58 pm    Post subject: Re: Beware of Radio Shack Reply with quote

In comp.sys.mac.system CBFalconer <cbfalconer@yahoo.com> wrote:
Quote:
Paul Nevai wrote:
"Jim Douglas" <james.douglas@genesis-software.com> aszonygya:

But they still argue they need it. Eventually I win or
I walk out with my money and no product.

Next time just give my phone and SS#: 1-800-555-5555 and
999-99-9999. I don't mind it. /Paul

I prefer to use mine; there is more chance they'll put it into
their system: 1-area-555-1212 and 123-54-9876.


I just say "that's classified". The blank stare goes awaya after a
few seconds and they ring me up ...
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steve
electronics forum beginner


Joined: 29 Mar 2005
Posts: 1

PostPosted: Tue Mar 29, 2005 1:56 pm    Post subject: Re: 10m-10cm distance measurement with 1cm accuracy at a rate of 50Hz Reply with quote

Try the Sharp GP2D12 sensors.

Steve

<Yugo> schreef in bericht
news:4242a351$0$29448$afc38c87@news.optusnet.com.au...
Quote:
Do you know any small size, light weight distance sensor with the
following specs;
* Range : 10cm to 1000cm (10meter )
* Rate : 50 Hz (50 measurements/sec)
* Accuracy : 1cm
* Must operate on any surface (except transparent surfaces like glass)
* Power requirement : Less than 5W
* Weight : Lighter than 500grams
* Vibrartion sensitivity : Must operate 0-500Hz
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Google

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