Polaroid 6500 Sensors and more!
Hello,
I have hooked up the 6500 ranging sensors, but, I am trying to get
them to operate to sense around the 6" range. Unfortuneately, it
only senses things past 17-18"... does anyone know how i can get this
to work around the 6" range? Please.. I really need info on this!
Its very important that I get this to work, otherwise, my term
project is useless!
Another thing, how can I do error checking if I'm sending data via an
RF transceiver? I have a computer and a robot and each have a
transceiver. However, there is some error in the transfer, and I
need to know how to do error checking, if possible. The computer is
running a C program.
Thanks!
Debu
I have hooked up the 6500 ranging sensors, but, I am trying to get
them to operate to sense around the 6" range. Unfortuneately, it
only senses things past 17-18"... does anyone know how i can get this
to work around the 6" range? Please.. I really need info on this!
Its very important that I get this to work, otherwise, my term
project is useless!
Another thing, how can I do error checking if I'm sending data via an
RF transceiver? I have a computer and a robot and each have a
transceiver. However, there is some error in the transfer, and I
need to know how to do error checking, if possible. The computer is
running a C program.
Thanks!
Debu
Comments
I used a bunch of 6500 sensors and I couldn't get them to work that
far. You need to play around with the BINH and BLNK pins to
adjust for close and small objects.
Original Message
From: "debu_sen_22" <debu_sen_22@y...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, February 08, 2002 1:16 AM
Subject: [noparse][[/noparse]basicstamps] Polaroid 6500 Sensors and more!
> Hello,
>
> I have hooked up the 6500 ranging sensors, but, I am trying to get
> them to operate to sense around the 6" range. Unfortuneately, it
> only senses things past 17-18"... does anyone know how i can get this
> to work around the 6" range? Please.. I really need info on this!
> Its very important that I get this to work, otherwise, my term
> project is useless!
>
> Another thing, how can I do error checking if I'm sending data via an
> RF transceiver? I have a computer and a robot and each have a
> transceiver. However, there is some error in the transfer, and I
> need to know how to do error checking, if possible. The computer is
> running a C program.
>
> Thanks!
>
> Debu
>
>
> 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/
>
>
>
wrote:
check out www.acroname.com they have info on the 6500,
as well as other types.. and sample code to use with
many types of microcontrollers...
> Hi,
>
> I used a bunch of 6500 sensors and I couldn't get
> them to work that
> far. You need to play around with the BINH and BLNK
> pins to
> adjust for close and small objects.
>
>
Original Message
> From: "debu_sen_22" <debu_sen_22@y...>
> To: <basicstamps@yahoogroups.com>
> Sent: Friday, February 08, 2002 1:16 AM
> Subject: [noparse][[/noparse]basicstamps] Polaroid 6500 Sensors and
> more!
>
>
> > Hello,
> >
> > I have hooked up the 6500 ranging sensors, but, I
> am trying to get
> > them to operate to sense around the 6" range.
> Unfortuneately, it
> > only senses things past 17-18"... does anyone know
> how i can get this
> > to work around the 6" range? Please.. I really
> need info on this!
> > Its very important that I get this to work,
> otherwise, my term
> > project is useless!
> >
> > Another thing, how can I do error checking if I'm
> sending data via an
> > RF transceiver? I have a computer and a robot and
> each have a
> > transceiver. However, there is some error in the
> transfer, and I
> > need to know how to do error checking, if
> possible. The computer is
> > running a C program.
> >
> > Thanks!
> >
> > Debu
> >
> >
> > 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/
> >
> >
> >
>
>
> 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/
>
>
__________________________________________________
Do You Yahoo!?
Send FREE Valentine eCards with Yahoo! Greetings!
http://greetings.yahoo.com
These have a range of 3cm to 3 meters. They cost $25 available from
www.acroname.com
I have used them, and found them to be a highly reliable sensor. Acroname
also has programming examples for the BS2.
I wrote an article on these for N&V it will be out in the april issue.
Very respectfully, your obedient servant.
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
Thank you everyone for your feedback, however, we have purchased the
6500 sensors, and our budget for our design project will not let us
change to a new type...
Thanks
--- In basicstamps@y..., Kerry Barlow <admin@m...> wrote:
> You could just not use the 6500 and instead use a devontech srf04
sensor.
> These have a range of 3cm to 3 meters. They cost $25 available from
> www.acroname.com
> I have used them, and found them to be a highly reliable sensor.
Acroname
> also has programming examples for the BS2.
> I wrote an article on these for N&V it will be out in the april
issue.
>
> Very respectfully, your obedient servant.
> 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
anything closer that what you have already detected. The sound transmitter
and receiver need a short blanking period after sending the sound pulse to
avoid drowning out the receiver with noise from the transmitted pulse).
Since the device has one big transducer, you have to let it settle down
longer, which means you can't get ranges down too close.
The Devantech units, has two transducers, one for transmit and one for
receive, and the units are smaller, so they have less blanking or settling
time between pulses. So you can get down to a couple of inches or less even
in some cases. But they don't go much beyond about 68-72 inches in range.
If your using this for a maze robot, your pretty much SOL, as the two side
walls are too close together for the size mazes they use.
A.) One suggestion is to add the Devantech range finders to your devices to
suppliment the Polaroid ones. Then the Polariod would work for longer ranges
and the Deventech for short ranges.
B.) Another suggestion is to maybe try a crossfiring method. Where you would
move the Polaroid unit father back on your device, maybe at the rear
pointing forward. Then you might be able to get it closer as you can
subtract the length of your device from the ranges being detected. But then
this idea may not help you if your design is fixed.
C.)You could also use a IR range/object detector like the Sharp GP2D02
(www.acroname.com) for close range distance measuring as well, to suppliment
the Polaroid range finder. Depending on the IR devices chosen, this can be
anything from simple object detection to the more precise Devantech units,
with costs varying from a few dollars up to $21 for one of the Devantech
units.
D.) A final thought might be to use an object opposite from the one coming
in too close. For example two walls in a hallway. You can measure the
distance to the walls front and back. This gives you the total length of the
hallway (or width as well maybe), then as you approach the far wall, you can
use the opposite wall's range to tell you how close your coming, when the
near wall goes under the minimum range detected. A method like this should
let you get down to 1/2" or less. Thus if the walls are say 20 feet apart,
the rear near wall is now in the garbage range, the front wall is measured
at 19 feet. As you approach the front wall, the rear wall becomes
measurable, then as you get too close the front wall becomes unmeasurable,
but the rear wall can be measured now. You can subtract the length of your
device to get a more accurate distance from the front wall.
Original Message
From: debu_sen_22 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=745bFrBYt5SAT-OKSekyK19SUnRL046qniP4EsAaWp8Tz5ictnjqWrmZ78R8chFGkzI6mlS9wOuOVG7MWQ]debu_sen_22@y...[/url
Sent: Monday, February 11, 2002 11:12 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: Polaroid 6500 Sensors and more!
Hi
Thank you everyone for your feedback, however, we have purchased the
6500 sensors, and our budget for our design project will not let us
change to a new type...
Thanks
--- In basicstamps@y..., Kerry Barlow <admin@m...> wrote:
> You could just not use the 6500 and instead use a devontech srf04
sensor.
> These have a range of 3cm to 3 meters. They cost $25 available from
> www.acroname.com
> I have used them, and found them to be a highly reliable sensor.
Acroname
> also has programming examples for the BS2.
> I wrote an article on these for N&V it will be out in the april
issue.
>
> Very respectfully, your obedient servant.
> 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:
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I don't get it then why does it say that they can detect at a much
lower distance than the 17 inches?
Well, I am discussing it with my group members, and, it doesn't seem
like our budget will let us change to IR sensors. They cost about
$22, and we would require to get 4 of them. Is there anyone out
there who's willing to sell us some cheap cheap GPD02 (Sharp) IR
sensors?
Thanks
DS
--- In basicstamps@y..., "Earl Bollinger" <earlwbollinger@a...> wrote:
>
> Unfortunately, Polaroid range detectors, by their nature, can't
detect
> anything closer that what you have already detected. The sound
transmitter
> and receiver need a short blanking period after sending the sound
pulse to
> avoid drowning out the receiver with noise from the transmitted
pulse).
> Since the device has one big transducer, you have to let it settle
down
> longer, which means you can't get ranges down too close.
> The Devantech units, has two transducers, one for transmit and one
for
> receive, and the units are smaller, so they have less blanking or
settling
> time between pulses. So you can get down to a couple of inches or
less even
> in some cases. But they don't go much beyond about 68-72 inches in
range.
>
> If your using this for a maze robot, your pretty much SOL, as the
two side
> walls are too close together for the size mazes they use.
>
> A.) One suggestion is to add the Devantech range finders to your
devices to
> suppliment the Polaroid ones. Then the Polariod would work for
longer ranges
> and the Deventech for short ranges.
> B.) Another suggestion is to maybe try a crossfiring method. Where
you would
> move the Polaroid unit father back on your device, maybe at the rear
> pointing forward. Then you might be able to get it closer as you can
> subtract the length of your device from the ranges being detected.
But then
> this idea may not help you if your design is fixed.
> C.)You could also use a IR range/object detector like the Sharp
GP2D02
> (www.acroname.com) for close range distance measuring as well, to
suppliment
> the Polaroid range finder. Depending on the IR devices chosen, this
can be
> anything from simple object detection to the more precise Devantech
units,
> with costs varying from a few dollars up to $21 for one of the
Devantech
> units.
> D.) A final thought might be to use an object opposite from the one
coming
> in too close. For example two walls in a hallway. You can measure
the
> distance to the walls front and back. This gives you the total
length of the
> hallway (or width as well maybe), then as you approach the far
wall, you can
> use the opposite wall's range to tell you how close your coming,
when the
> near wall goes under the minimum range detected. A method like this
should
> let you get down to 1/2" or less. Thus if the walls are say 20 feet
apart,
> the rear near wall is now in the garbage range, the front wall is
measured
> at 19 feet. As you approach the front wall, the rear wall becomes
> measurable, then as you get too close the front wall becomes
unmeasurable,
> but the rear wall can be measured now. You can subtract the length
of your
> device to get a more accurate distance from the front wall.
>
>
>
>
Original Message
> From: debu_sen_22 [noparse][[/noparse]mailto:debu_sen_22@y...]
> Sent: Monday, February 11, 2002 11:12 PM
> To: basicstamps@y...
> Subject: [noparse][[/noparse]basicstamps] Re: Polaroid 6500 Sensors and more!
>
>
> Hi
>
> Thank you everyone for your feedback, however, we have purchased the
> 6500 sensors, and our budget for our design project will not let us
> change to a new type...
>
> Thanks
>
>
> --- In basicstamps@y..., Kerry Barlow <admin@m...> wrote:
> > You could just not use the 6500 and instead use a devontech srf04
> sensor.
> > These have a range of 3cm to 3 meters. They cost $25 available
from
> > www.acroname.com
> > I have used them, and found them to be a highly reliable sensor.
> Acroname
> > also has programming examples for the BS2.
> > I wrote an article on these for N&V it will be out in the april
> issue.
> >
> > Very respectfully, your obedient servant.
> > 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@y...
> 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/
field.
In other words when the sensor reads 18 inches or more the focus is set the
same as the reading, but when the sensor reads minimum the focus actually
gets set to 12 inches but with the tight aperture's depth of field objects
between 6 and 24 inches are somewhat focused in.
KF4HAZ - Lonnie
Original Message
From: "debu_sen_22" <debu_sen_22@
> Hey...thanks for the info.
>
> I don't get it then why does it say that they can detect at a much
> lower distance than the 17 inches?
>
> Well, I am discussing it with my group members, and, it doesn't seem
> like our budget will let us change to IR sensors. They cost about
> $22, and we would require to get 4 of them. Is there anyone out
> there who's willing to sell us some cheap cheap GPD02 (Sharp) IR
> sensors?
>
> Thanks
> DS
require, be aware however that it fails in detecting very narrow objects.
If you need to detect a wall, or large object, no problem. If you are
trying to detect something narrow such as a chair leg in circumfrance, then
the Sharp sensors will miss detection at times. You may want to look at the
specs on the Devontech SRF04 sensor.
http://www.acroname.com/robotics/parts/R93-SRF04.html
I am affiliated in no way with them, I just however have used both the Sharp
and the Devontech. In my application for robotics, I was always finding the
Sharp allowing my robot to run into chair legs. Doh doh doh.
I understand that your budget has you limited now. Good luck to you!
Have you thought of the polaroid for longer range, and cheap $2 IR sensors
for close in range detection? The ones that Parallax sells I was thinking
of. I forgot what brand they are off hand, Phillips?
-kerry
At 09:25 AM 2/12/02 -0600, you wrote:
>Polaroid's claim is based on using tight aperture which improves depth of
>field.
>In other words when the sensor reads 18 inches or more the focus is set the
>same as the reading, but when the sensor reads minimum the focus actually
>gets set to 12 inches but with the tight aperture's depth of field objects
>between 6 and 24 inches are somewhat focused in.
>
>KF4HAZ - Lonnie
>
>
Original Message
From: "debu_sen_22" <debu_sen_22@
>> Hey...thanks for the info.
>>
>> I don't get it then why does it say that they can detect at a much
>> lower distance than the 17 inches?
>>
>> Well, I am discussing it with my group members, and, it doesn't seem
>> like our budget will let us change to IR sensors. They cost about
>> $22, and we would require to get 4 of them. Is there anyone out
>> there who's willing to sell us some cheap cheap GPD02 (Sharp) IR
>> sensors?
>>
>> Thanks
>> DS
>
>
>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/
>
>
>
Very respectfully, your obedient servant.
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
upright on the bench by scanning back and forth and centering on the
positions where the outer edge of the beam detects a closer object.
Original Message
> The sharp GPD02 sensor is a very good sensor, and has short range as you
> require, be aware however that it fails in detecting very narrow objects.
> If you need to detect a wall, or large object, no problem. If you are
> trying to detect something narrow such as a chair leg in circumfrance,
then
> the Sharp sensors will miss detection at times. You may want to look at
the
> specs on the Devontech SRF04 sensor.
> http://www.acroname.com/robotics/parts/R93-SRF04.html
> I am affiliated in no way with them, I just however have used both the
Sharp
> and the Devontech. In my application for robotics, I was always finding
the
> Sharp allowing my robot to run into chair legs. Doh doh doh.
> I understand that your budget has you limited now. Good luck to you!
> Have you thought of the polaroid for longer range, and cheap $2 IR sensors
> for close in range detection? The ones that Parallax sells I was thinking
> of. I forgot what brand they are off hand, Phillips?
good as the older original ones.
At that time no one had mentioned anything about apertures and how to set
them.
You can goto www.parallaxinc.com and check out the IR transmitter and the IR
detector devices, like they use in the Basic Stamps Robotics manual
experiments. Check out the robotics manual. I think the detector cost $5.50
and the transmitter cost $2.50. Basically, you output a 38,000 hertz pulse
using the FREQOUT function, then you look on the detector with a FREQIN
function to see if you pick up a reflection. You can get fancy and use a 555
timer to do the FREQ out part too or some other method. Although I haven't
tried it you could use the Radio Shack IR transmitter and detector
phototransistors as well. Radio shack had these going for about $2.00 as a
matched set. But I haven't tried them yet to see how they work, so I don't
know. This low cost IR detector method works quite well, but you don't get
accurate ranging that way, you just get a object is detected.
Original Message
From: debu_sen_22 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=CQy8n3TtWtAiMhh8Xb5bqIcVtU-ElkT1MAM7pQeod_opctfkdmKzqp8ADkhvT-NU5ljEs-8lmuuIfqE-BA]debu_sen_22@y...[/url
Sent: Tuesday, February 12, 2002 8:58 AM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: Polaroid 6500 Sensors and more!
Hey...thanks for the info.
I don't get it then why does it say that they can detect at a much
lower distance than the 17 inches?
Well, I am discussing it with my group members, and, it doesn't seem
like our budget will let us change to IR sensors. They cost about
$22, and we would require to get 4 of them. Is there anyone out
there who's willing to sell us some cheap cheap GPD02 (Sharp) IR
sensors?
Thanks
DS
--- In basicstamps@y..., "Earl Bollinger" <earlwbollinger@a...> wrote:
>
> Unfortunately, Polaroid range detectors, by their nature, can't
detect
> anything closer that what you have already detected. The sound
transmitter
> and receiver need a short blanking period after sending the sound
pulse to
> avoid drowning out the receiver with noise from the transmitted
pulse).
> Since the device has one big transducer, you have to let it settle
down
> longer, which means you can't get ranges down too close.
> The Devantech units, has two transducers, one for transmit and one
for
> receive, and the units are smaller, so they have less blanking or
settling
> time between pulses. So you can get down to a couple of inches or
less even
> in some cases. But they don't go much beyond about 68-72 inches in
range.
>
> If your using this for a maze robot, your pretty much SOL, as the
two side
> walls are too close together for the size mazes they use.
>
> A.) One suggestion is to add the Devantech range finders to your
devices to
> suppliment the Polaroid ones. Then the Polariod would work for
longer ranges
> and the Deventech for short ranges.
> B.) Another suggestion is to maybe try a crossfiring method. Where
you would
> move the Polaroid unit father back on your device, maybe at the rear
> pointing forward. Then you might be able to get it closer as you can
> subtract the length of your device from the ranges being detected.
But then
> this idea may not help you if your design is fixed.
> C.)You could also use a IR range/object detector like the Sharp
GP2D02
> (www.acroname.com) for close range distance measuring as well, to
suppliment
> the Polaroid range finder. Depending on the IR devices chosen, this
can be
> anything from simple object detection to the more precise Devantech
units,
> with costs varying from a few dollars up to $21 for one of the
Devantech
> units.
> D.) A final thought might be to use an object opposite from the one
coming
> in too close. For example two walls in a hallway. You can measure
the
> distance to the walls front and back. This gives you the total
length of the
> hallway (or width as well maybe), then as you approach the far
wall, you can
> use the opposite wall's range to tell you how close your coming,
when the
> near wall goes under the minimum range detected. A method like this
should
> let you get down to 1/2" or less. Thus if the walls are say 20 feet
apart,
> the rear near wall is now in the garbage range, the front wall is
measured
> at 19 feet. As you approach the front wall, the rear wall becomes
> measurable, then as you get too close the front wall becomes
unmeasurable,
> but the rear wall can be measured now. You can subtract the length
of your
> device to get a more accurate distance from the front wall.
>
>
>
>
Original Message
> From: debu_sen_22 [noparse][[/noparse]mailto:debu_sen_22@y...]
> Sent: Monday, February 11, 2002 11:12 PM
> To: basicstamps@y...
> Subject: [noparse][[/noparse]basicstamps] Re: Polaroid 6500 Sensors and more!
>
>
> Hi
>
> Thank you everyone for your feedback, however, we have purchased the
> 6500 sensors, and our budget for our design project will not let us
> change to a new type...
>
> Thanks
>
>
> --- In basicstamps@y..., Kerry Barlow <admin@m...> wrote:
> > You could just not use the 6500 and instead use a devontech srf04
> sensor.
> > These have a range of 3cm to 3 meters. They cost $25 available
from
> > www.acroname.com
> > I have used them, and found them to be a highly reliable sensor.
> Acroname
> > also has programming examples for the BS2.
> > I wrote an article on these for N&V it will be out in the april
> issue.
> >
> > Very respectfully, your obedient servant.
> > 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@y...
> 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/
To UNSUBSCRIBE, just send mail to:
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from the same email address that you subscribed. Text in the Subject and
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Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
section on sensors.. To include two or three types of
the sharp ir ranger you are speaking of. As well as
polaroid rangers, ans devanchi sonar rangers.. wich I
think are much better....
--- Earl Bollinger <earlwbollinger@a...> wrote:
> The best I got was around 2 feet minimum, maybe the
> newer ones aren't as
> good as the older original ones.
> At that time no one had mentioned anything about
> apertures and how to set
> them.
>
> You can goto www.parallaxinc.com and check out the
> IR transmitter and the IR
> detector devices, like they use in the Basic Stamps
> Robotics manual
> experiments. Check out the robotics manual. I think
> the detector cost $5.50
> and the transmitter cost $2.50. Basically, you
> output a 38,000 hertz pulse
> using the FREQOUT function, then you look on the
> detector with a FREQIN
> function to see if you pick up a reflection. You can
> get fancy and use a 555
> timer to do the FREQ out part too or some other
> method. Although I haven't
> tried it you could use the Radio Shack IR
> transmitter and detector
> phototransistors as well. Radio shack had these
> going for about $2.00 as a
> matched set. But I haven't tried them yet to see how
> they work, so I don't
> know. This low cost IR detector method works quite
> well, but you don't get
> accurate ranging that way, you just get a object is
> detected.
>
>
Original Message
> From: debu_sen_22 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=1mHL8YD0eFXy-fA0Oe_FCTCE8A72hOgjmZatbAeX-mn60vA-4Nc6VREPKa97rYwqQocvirUtG3oyCVM]debu_sen_22@y...[/url
> Sent: Tuesday, February 12, 2002 8:58 AM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Re: Polaroid 6500 Sensors and
> more!
>
>
> Hey...thanks for the info.
>
> I don't get it then why does it say that they can
> detect at a much
> lower distance than the 17 inches?
>
> Well, I am discussing it with my group members, and,
> it doesn't seem
> like our budget will let us change to IR sensors.
> They cost about
> $22, and we would require to get 4 of them. Is
> there anyone out
> there who's willing to sell us some cheap cheap
> GPD02 (Sharp) IR
> sensors?
>
> Thanks
> DS
>
>
>
> --- In basicstamps@y..., "Earl Bollinger"
> <earlwbollinger@a...> wrote:
> >
> > Unfortunately, Polaroid range detectors, by their
> nature, can't
> detect
> > anything closer that what you have already
> detected. The sound
> transmitter
> > and receiver need a short blanking period after
> sending the sound
> pulse to
> > avoid drowning out the receiver with noise from
> the transmitted
> pulse).
> > Since the device has one big transducer, you have
> to let it settle
> down
> > longer, which means you can't get ranges down too
> close.
> > The Devantech units, has two transducers, one for
> transmit and one
> for
> > receive, and the units are smaller, so they have
> less blanking or
> settling
> > time between pulses. So you can get down to a
> couple of inches or
> less even
> > in some cases. But they don't go much beyond about
> 68-72 inches in
> range.
> >
> > If your using this for a maze robot, your pretty
> much SOL, as the
> two side
> > walls are too close together for the size mazes
> they use.
> >
> > A.) One suggestion is to add the Devantech range
> finders to your
> devices to
> > suppliment the Polaroid ones. Then the Polariod
> would work for
> longer ranges
> > and the Deventech for short ranges.
> > B.) Another suggestion is to maybe try a
> crossfiring method. Where
> you would
> > move the Polaroid unit father back on your device,
> maybe at the rear
> > pointing forward. Then you might be able to get it
> closer as you can
> > subtract the length of your device from the ranges
> being detected.
> But then
> > this idea may not help you if your design is
> fixed.
> > C.)You could also use a IR range/object detector
> like the Sharp
> GP2D02
> > (www.acroname.com) for close range distance
> measuring as well, to
> suppliment
> > the Polaroid range finder. Depending on the IR
> devices chosen, this
> can be
> > anything from simple object detection to the more
> precise Devantech
> units,
> > with costs varying from a few dollars up to $21
> for one of the
> Devantech
> > units.
> > D.) A final thought might be to use an object
> opposite from the one
> coming
> > in too close. For example two walls in a hallway.
> You can measure
> the
> > distance to the walls front and back. This gives
> you the total
> length of the
> > hallway (or width as well maybe), then as you
> approach the far
> wall, you can
> > use the opposite wall's range to tell you how
> close your coming,
> when the
> > near wall goes under the minimum range detected. A
> method like this
> should
> > let you get down to 1/2" or less. Thus if the
> walls are say 20 feet
> apart,
> > the rear near wall is now in the garbage range,
> the front wall is
> measured
> > at 19 feet. As you approach the front wall, the
> rear wall becomes
> > measurable, then as you get too close the front
> wall becomes
> unmeasurable,
> > but the rear wall can be measured now. You can
> subtract the length
> of your
> > device to get a more accurate distance from the
> front wall.
> >
> >
> >
> >
Original Message
> > From: debu_sen_22 [noparse][[/noparse]mailto:debu_sen_22@y...]
> > Sent: Monday, February 11, 2002 11:12 PM
> > To: basicstamps@y...
> > Subject: [noparse][[/noparse]basicstamps] Re: Polaroid 6500 Sensors
> and more!
> >
> >
> > Hi
> >
> > Thank you everyone for your feedback, however, we
> have purchased the
> > 6500 sensors, and our budget for our design
> project will not let us
> > change to a new type...
> >
> > Thanks
> >
> >
> > --- In basicstamps@y..., Kerry Barlow <admin@m...>
> wrote:
> > > You could just not use the 6500 and instead use
> a devontech srf04
> > sensor.
> > > These have a range of 3cm to 3 meters. They cost
> $25 available
> from
> > > www.acroname.com
> > > I have used them, and found them to be a highly
> reliable
=== message truncated ===
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