Subject:
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Steering Drive
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 25 Aug 2004 02:20:16 GMT
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Reply-To:
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ROBOTS@DEELETEF3avoidspamP.COM
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Viewed:
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891 times
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So I'm building this robot because my FLL kids told me it couldn't be
done. It has to do a few things, line following, bumpers, nothing too
special. I made it with a steering drive because it has to have
wheels that turn to make it look right (I'll explain after it's done,
I have to keep the design a secret for another 2 weeks). Not a big
problem, I'm using the basic linkage that came with the racers
(8473-1) I got at the Brickfest outlet store sale. I've got a
differential in there with a motor to drive it, and a rotation sensor
hooked up for distance measuring. I have a light sensor for finding
the line I'm going to follow. Here's the tricky part. I have a touch
sensor hooked up much like this one
(http://www.marioferrari.org/brlm/f1614.jpg) so that I can tell when
the wheels are pointed straight ahead.
So my problem is, how do I tell which way I need to turn the motor to
get the wheels back to straight?
If the sensor is touched, I know that it is going straight, but if the
sensor is not touched I can't figure out any good way to tell which
side of the switch the cam is on. At least, not without using another
sensor port, which I don't have available. I can't double up on the
light sensor, because I can't have the sensor value go to 100 just
because I'm going straight.
Help. Any advice appreciated.
-Jon
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Message has 6 Replies:
 | | Re: Steering Drive
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| How precise does the distance measuring have to be? Why not use the rotation sensor for the steering position, and use the touch sensor in an arrangement similar to a land-measuring wheel (one click equals x distance) for the distance? That'd be my (...) (20 years ago, 25-Aug-04, to lugnet.robotics)
| | | Re: Steering Drive
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| (...) Well, you can use a second touch sensor and a raised portion on half the steering rack so that it is always depressed when not in the center or the other half. This second sensor can be multiplexed with a passive sensor such as you would find (...) (20 years ago, 25-Aug-04, to lugnet.robotics)
| | | Re: Steering Drive
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| (...) Instead you could have another light sensor, and something like this (URL) attached to the steering shaft. That way the light sensor can tell 3 different states - straight, left or right. ROSCO (20 years ago, 25-Aug-04, to lugnet.robotics)
| | | Re: Steering Drive
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| "Jon Gilchrist" <robots@DEELEETEf3p.com> wrote in message news:cmsni0t76f5vr92...4ax.com... (...) Initialize the steering by running the motor at a low power setting in one direction for a short period of time. If it does not engage the touch (...) (20 years ago, 25-Aug-04, to lugnet.robotics)
| | | Re: Steering Drive
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| --- Jon Gilchrist <robots@DEELEETEf3p.com> wrote: [snip] (...) It also just occured to me that if you want to avoid multiplexing with external parts, the line sensor can be doubled up with a touch sensor. If the bumper switch is doubled up on the (...) (20 years ago, 25-Aug-04, to lugnet.robotics)
| | | Re: Steering Drive
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| "Jon Gilchrist" <robots@DEELEETEf3p.com> wrote in message news:cmsni0t76f5vr92...4ax.com... (...) I don't understand why you need to know which way to turn the wheels to go straight? When you initialize the robot you can test with low power first (...) (20 years ago, 25-Aug-04, to lugnet.robotics)
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