Re: New Ultrasonic Range Sensor

Bob (Robot Wars Thumper 1997) wrote: 
Stef,

The beam shapes shown in the datasheet are correct.

The sensor has a long-range detection distance and a narrow beam.

It was a lot of work to design the sensor but, not impossible.

The MaxSonar-EZ1 is not a copy of anything else out there.  It is an
original design, designed to overcome the above mentioned problems and
much more.

The MaxSonar-EZ1 has a stable range output.  It has a very narrow beam
and has long range.  It works to look down a hall or in my living room
or in a robot contest.

I also started with two sensors, but it was not possible to detect to
zero so I switched to just one sensor.  In addition, two sensor models
have a blind spot in between the sensors as one gets closer.  Again I
did not what the sensor to have a blind spot.

I noticed the mentioning of Devantech Ltd. on the bottom of your page.
To this I respond with the text below.  (The text below I posted  on
another group and further addresses your comments.)

One of the reasons I completed this sensor was because my daughters
robot was stuck on a wall (it was too close) during a contest.  The
sensor that was on the robot was one of most popular two sensor models,
but when too close, it was blind.


The easy solution, of course, is to set the ultrasonics back from the edge of the robot so the blind spot starts within the measurements of the platform. Then utilize bumper switches or short-range IR to detect zero-distance objects if necessary. Not too elegant, but straightforward enough.

However, you chose the hard solution, and I have to applaud you for that. Instead of giving up on the fully ultrasonic sensor you've created something that will be helpful to many robot builders and other distance applications in the future. I'm sure the big guys are dropping their teeth about now upon seeing your single-transducer solution and low price.

One question I have, if it's not too much trouble: any chance of adding one or two more bits to the distance resolution, or calibrating for a shorter distance with smaller increments? I realize timing is probably tight in your microcontroller but additional resolution could turn out to be handy sometimes.
.

Relevant Pages

  • Re: Any simple collision detection ideas?
    ... I am trying to build a foot touch sensor mechanism for my hexapod ... walking robot using force sense resistors. ... But i would like bump sensing as well... ...
    (comp.robotics.misc)
  • Re: New Sonar Range Sensor
    ... One of the reasons I completed this sensor was because my daughters ... robot was stuck on a wall during a contest. ... The next problem was that this dual sensor beam width was much too wide ... Again, thanks for your thumbs up on the design, but I really wanted to ...
    (comp.robotics.misc)
  • Re: Algorithm for counting number of lines travelled over
    ... It's as if the while loop is never entered or is ... > why the robot just stops immediately upon being activated. ... > because one is looking for a white surface, ... out of the sensor. ...
    (comp.robotics.misc)
  • Reading barcodes using a laser scanner
    ... sensor to detect reflector targets that have barcodes on them. ... The barcode is to allow the robot to know which of the targets it has ... I see the scribbler robot has the ability to detect barcodes using its ...
    (comp.robotics.misc)