Subject:
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Re: Mindstorms Novice
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Newsgroups:
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lugnet.robotics
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Date:
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Mon, 8 Feb 1999 00:22:49 GMT
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Viewed:
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1082 times
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It was suggested to me that posing my questions on the newsgroup might
be better than using e-mail. So here it goes :) So far, I have tried
the first two pathfinder challenges - the "Outback Tracker" and the
"Light Tracker." I have also tried to build a simple walker based on
the constructopedia legs on p. 27. I had more luck with the light
tracker, so let me start there with some of my concerns and questions.
Light Tracker:
I was able to make a simple pathfinder-based robot that would move
toward the light when it was shone on it. I had to modify the pre-made
program (limiting it) so that the bot would just turn slowly by
activating either motor a or c for a random interval between 1 and 10.
Once the light was detected, both motors were set to on and speed was
increased. This worked fairly well for me. I am concerned however that
I had to limit the program to just turning the bot left and right
instead of moving all around (as the objective stated). Also, and this
is my bigger concern, I don't think the light signal was picked up by
the light sensor consistently. Sometimes the "eye" would pass right
through the beam of light without the program responding. I adjusted
the light/dark parameters and this helped somewhat, and slowing the
speed to "1" helped, but I still thought the bot should be more
responsive. My other question about this challenge is the stack
controller "check & choose light." The pre-made program uses two "C&CL"
controllers. In each one a series of commands is presented under the
"true" condition. Why not just use one controller and put the dark
value "true" commands under the light value "false" section? Any
thoughts on this challenge would be most appreciated.
Outback Tracker:
I didn't get very far in this challenge. I started by building a
v-shaped touch sensor bumper like #6 on page 30 in the Constructopedia.
Then I realized it didn't meet the design spec. which states that the
bot should move forward when BOTH sensors are pressed, left/right when
one is pressed, and stop when none are pressed. I'm having a hard time
imagining a bumper that depressed both sensors to move forward, but let
one go to steer. What would cause one sensor to release?
The other main problem I am having with this challenge is visualizing
exactly what sort of obstacle course the bot is supposed to navigate.
The test pad shows a direction course the bot is supposed to take, but
what kind of obstacles are in the way? I know this may sound like a
stupid question - but wouldn't the design of the obstacle course
determine how you designed the bot to navigate it? I mean, is the run
of the course bordered by walls, or are there only objects at certain
points (I used soup cans when I first tried this - the v-shaped bumper
would "capture" the cans in the v - unable to move left or right). I
appreciate any help you can give in further explaining this challenge to
me.
Walker:
I built a walker based on the leg design #7 on page 27 of the
Constructopedia. Unfortunately, everytime i tried to run this bot, my
motors would get so out of sync that it would barely move and instead
just sort of swayed from side to side. Are everyone's motors this
out-of sync? I rebuilt the model using only one motor to power both
wheels and it worked fine - except I can't steer with only one motor.
Any thoughts about the motor speed difference or work-around solutions
would be appreciated.
Thomas Main wrote:
>
> I just got the RIS and finished the tutorials on the CD. I started
> looking at the challenges and soon realized I could use some help. Is
> there someone here willing to help a novice gain proficiency with the
> RIS? I was hoping some sort of question-and-answer sessions could be
> established via e-mail. If you are interested in helping me, drop me a
> line at main@appstate.edu
>
> Thanks.
>
> --
> Thomas Main
> main@appstate.edu
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Message has 1 Reply:
 | | Re: Mindstorms Novice
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| (...) Ah-ha! This looks like a job for... (insert fanfare here) Leo's infamous "adder/subtractor", tentatively being called the "differtrans". Of course, you'll need another differential unit -- the RIS only comes with one. Spare parts set 5229 has (...) (26 years ago, 8-Feb-99, to lugnet.robotics)
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Message is in Reply To:
| | Mindstorms Novice
|
| I just got the RIS and finished the tutorials on the CD. I started looking at the challenges and soon realized I could use some help. Is there someone here willing to help a novice gain proficiency with the RIS? I was hoping some sort of (...) (26 years ago, 1-Feb-99, to lugnet.robotics)
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