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15853Re: SRF08 beam angle

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  • Phil
    Dec 1, 2003
    • 0 Attachment
      what about some sort of tuning "pipe" that you slip over the reciever
      to decrease the field of view that the receiver actually sees? sort
      of like blinders for a horse...

      also, different Transceivers have different characteristics. I'm not
      sure you want to take on building your own but I know that there are
      several that have much narrower patterns. For example, the murata MA
      A1 series (75Khz) shows a significantly narrower pattern and they
      claim a 7 degree directivity (if that's really a word...).

      Phil

      --- In SeattleRobotics@yahoogroups.com, "Karim Virani" <karim@c...>
      wrote:
      > Is there any physical way to confine the angle further - without
      throwing off the results? I'd like to reject everything outside of
      about 7 to 10 degrees from center, 15 to 20 degree total cone.
      >
      > Karim
      >
      >
      >
      > -----Original Message-----
      > From: dan michaels [mailto:dan@o...]
      > Sent: Monday, December 01, 2003 3:38 PM
      > To: SeattleRobotics@yahoogroups.com
      > Subject: [SeattleRobotics] Re: SRF08 beam angle
      >
      >
      > --- In SeattleRobotics@yahoogroups.com, "Alejandro Alonso Puig"
      > <alejandro.alonso@m...> wrote:
      > >
      > > Hi all,
      > >
      > > I've got a question. Does anyone of you know by experience what
      is
      > the angle
      > > of detection of the sonar ranger SRF08 from Devantech?.
      > >
      > > I have found some information on the Internet, but I don't
      believe
      > what I'm
      > > reading. I found that the angle detection is of about 40 degrees,
      > but in my
      > > tests I find it is about 100 degrees. SRF04 seems to really have
      40
      > degrees
      > > of beam angle, but not SRF08.
      > >
      > > The most interesting information I found about the beam pattern
      is
      > the graph
      > > taken from the manufacturer:
      > > http://www.robot-electronics.co.uk/htm/sonar_faq.htm but
      Devantech
      > really do
      > > not give a clear figure for the beam width. I just see that
      > depending on the
      > > decibels the beam is wider on narrower. My though is that the
      > transducer is
      > > used at about -18dB and therefore the cone width is about 100
      > degrees.
      > >
      > > But I'm not sure I'm doing correctly or my unit is wrong in some
      > way.
      > >
      > > Could someone please confirm from experience the beam width?
      > >
      > > Thanks a lot in advance
      > >
      > > Alejandro Alonso Puig
      > > http://mundobot.com
      > > alejandro.alonso@m...
      >
      >
      > Alonso, the beam width you measure will no doubt depend upon both
      the
      > size of your target, and also the distance away from the
      transducers.
      > If you use a large target up close, it will be detected over a much
      > wider angle than if you use a small target far away.
      >
      > If you take a look at the Acroname site, they show a slightly
      > different way of representing beam pattern than the diagram on the
      > robot-electronics site. It shows that a target 10 feet or more
      > distance will be detected over about 45 deg total angle, but if
      it's
      > only 2 feet distance then it will be detected over almost 90 deg.
      > Then factor in the width of the target, and you will get a slightly
      > larger angle, on top of this.
      >
      > http://acroname.com/robotics/parts/R145-SRF08.html
      >
      >
      > - dan michaels
      > www.oricomtech.com
      > ============================
      >
      >
      > Visit the SRS Website at http://www.seattlerobotics.org
      >
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