IR vs. Sonar
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Posts: 46,084
I am looking to add "Distance Detection" to my next Stamp II powered
robot. Which is better at determining the distance of an object...
Sharp IR Detectors (like the kind that Acroname sells) or Sonar
systems like the Devantech SRF04?
Which one is more accurate?
Which one is less susceptible false readings?
Which one works faster?
There are lots of articles about each, but I have not found much that
compares and contrast the advantages/disadvantages of each type.
Thanks,
Steve
robot. Which is better at determining the distance of an object...
Sharp IR Detectors (like the kind that Acroname sells) or Sonar
systems like the Devantech SRF04?
Which one is more accurate?
Which one is less susceptible false readings?
Which one works faster?
There are lots of articles about each, but I have not found much that
compares and contrast the advantages/disadvantages of each type.
Thanks,
Steve
Comments
discussing the pros and cons of IR sensors.
IR will tend to give false readings depending on wall colors, fabric, light
sources etc. The sharp series is also not good at detecting small objects
such as chair legs.
Speed of detection is faster with the devantech sonar as well.
I highly recommend the devantech srf04 sonar. I use it for my main obstacle
detection on my robot. It will pick up all small objects such as chair legs,
or small trees outdoors. The price is not that much more then a sharp
either. For a real world speed of detection. I used a yardstick, and passed
it across the Devantech at a moderate speed, at a range of 1 foot. It would
easily pick up the moving yardstick everytime. Approximatly the speed a
flagman waves a flag at you on the road. The sharp series would be hard
pressed to detect one movement let alone every one. One negative point of
the devantech is that it has a wide field of view. 40 degrees facing forward
in a cone shape. You may get a detection at a long range, and not know
exactly where the object was detected. For example was it on the left
forward, or right forward of the robot. I had a track robot setup to swing
the robot left 45 degrees, back to center, then right 45 degrees on an
obkect detection. This way I knew exactly where the object was. I later
placed a sharp IR sensor on a servo head. I detect an object with the
devantech. Then I rotate the servo/sensor head to find out exactly where the
object is. The narrow field of view of the sharp sensor allows me to do this.
Good luck, and have fun.
-Kerry
At 09:22 PM 4/15/03 -0000, you wrote:
>I am looking to add "Distance Detection" to my next Stamp II powered
>robot. Which is better at determining the distance of an object...
>Sharp IR Detectors (like the kind that Acroname sells) or Sonar
>systems like the Devantech SRF04?
>
>Which one is more accurate?
>Which one is less susceptible false readings?
>Which one works faster?
>
>There are lots of articles about each, but I have not found much that
>compares and contrast the advantages/disadvantages of each type.
>
>Thanks,
>
>Steve
>
>
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>
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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
607-775-1575
I am currently using both products, a sharp GPD05 and the Devantech
system for a science project, to find out exactly what your asking. So
far the Devantech system is the better of the two because it gives a
more accurate reading (in my findings). Even though the IR is 13$
cheaper, the Devantech system is the way to go. You can see my bot on
the yahoogroups website, under the folder Kirby which employs both, but
is pictured with the Devantech finder.
-Mike
Original Message
From: Kerry Barlow [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=MT8vbRIK_YgT-uKlcHlYaVQt6hVJOkTXR5MV0_QxN45kbvOEmxh3InaMf9D8qZdM07GrUafjSQ8]admin@m...[/url
Sent: Tuesday, April 15, 2003 5:56 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] IR vs. Sonar
I wrote an article for N&V april 2002 regarding the Devantech srf04:
discussing the pros and cons of IR sensors.
IR will tend to give false readings depending on wall colors, fabric,
light
sources etc. The sharp series is also not good at detecting small
objects
such as chair legs.
Speed of detection is faster with the devantech sonar as well.
I highly recommend the devantech srf04 sonar. I use it for my main
obstacle
detection on my robot. It will pick up all small objects such as chair
legs,
or small trees outdoors. The price is not that much more then a sharp
either. For a real world speed of detection. I used a yardstick, and
passed
it across the Devantech at a moderate speed, at a range of 1 foot. It
would
easily pick up the moving yardstick everytime. Approximatly the speed a
flagman waves a flag at you on the road. The sharp series would be hard
pressed to detect one movement let alone every one. One negative point
of
the devantech is that it has a wide field of view. 40 degrees facing
forward
in a cone shape. You may get a detection at a long range, and not know
exactly where the object was detected. For example was it on the left
forward, or right forward of the robot. I had a track robot setup to
swing
the robot left 45 degrees, back to center, then right 45 degrees on an
obkect detection. This way I knew exactly where the object was. I later
placed a sharp IR sensor on a servo head. I detect an object with the
devantech. Then I rotate the servo/sensor head to find out exactly where
the
object is. The narrow field of view of the sharp sensor allows me to do
this.
Good luck, and have fun.
-Kerry
At 09:22 PM 4/15/03 -0000, you wrote:
>I am looking to add "Distance Detection" to my next Stamp II powered
>robot. Which is better at determining the distance of an object...
>Sharp IR Detectors (like the kind that Acroname sells) or Sonar
>systems like the Devantech SRF04?
>
>Which one is more accurate?
>Which one is less susceptible false readings?
>Which one works faster?
>
>There are lots of articles about each, but I have not found much that
>compares and contrast the advantages/disadvantages of each type.
>
>Thanks,
>
>Steve
>
>
>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
607-775-1575
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.
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The SRF04 has more range and returns a value that can be directly converted
to distance. It has a fairly wide pattern and would be good for object
avoidance. With some work it is also good for object detection.
The Sharp sensors have a much shorter range and return a non-linear voltage
or value that would have to be converted to get the distance. They have a
much narrower pattern, which is better for object detection. You would need
to scan them to use them for object avoidance.
I have two GP2D02's and an SRF04 on my big robot, all mounted on a disk that
will turn 90 degrees. Everything is run off a BS2SX, and It works for wall
following, object detection, etc....
Original Message
> I am looking to add "Distance Detection" to my next Stamp II powered
> robot. Which is better at determining the distance of an object...
> Sharp IR Detectors (like the kind that Acroname sells) or Sonar
> systems like the Devantech SRF04?
>
> Which one is more accurate?
> Which one is less susceptible false readings?
> Which one works faster?
>
> There are lots of articles about each, but I have not found much that
> compares and contrast the advantages/disadvantages of each type.
ease of use. Both can be fooled by certain materials and shapes. They are
both pretty accurate within their ranges. The SRF04 and the Gp2D02 take
about the same time to make a reading.
The GP2d02 is less expensive and uses less power. The annoying thing about
it is that it has a very narrow field of view. I use two of them facing
slightly towards each other or I use a servo to swivel one back and forth.
There is also a version of these that outputs different voltage to show
distance. The Stamp doesn't do ADC, but a you could use a ADC chip to
convert the voltage. These analog versions are also power hogs and use
about the same current as the SRF04.
The SRF04 is nice, but a bit pricey I think. It's also uses a lot of power.
The SRF08 uses less juice, but is twice the cost.
If you are adventurous, you might look into Circuit Cellar's PSoC Sonar
ranger project. It uses a Cypress PSoC chip and two sonar transducers to
make a sonar ranger. The initial outlay of the price of the programmer is
$25 [noparse][[/noparse]Digikey], but the chips themselves are pretty inexpensive and the
software is free. Once you get the hang of the PSoC you could build a Sonar
ranger for $14 ~ $18 ($7 for the PSoC [noparse][[/noparse]Digikey], $7 for the transducers +
plus misc components).
check out:
http://stage.cypressmicro.com/
chris in napa
Original Message
From: "sjoblin001" <steven_joblin@h...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, April 15, 2003 2:22 PM
Subject: [noparse][[/noparse]basicstamps] IR vs. Sonar
> I am looking to add "Distance Detection" to my next Stamp II powered
> robot. Which is better at determining the distance of an object...
> Sharp IR Detectors (like the kind that Acroname sells) or Sonar
> systems like the Devantech SRF04?
>
> Which one is more accurate?
> Which one is less susceptible false readings?
> Which one works faster?
>
> There are lots of articles about each, but I have not found much that
> compares and contrast the advantages/disadvantages of each type.
>
> Thanks,
>
> Steve
>
>
> 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/
>
>