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Subject: 
Re: proud of myself (+ some questions)
Newsgroups: 
lugnet.robotics
Date: 
Fri, 17 Sep 1999 08:47:06 GMT
Original-From: 
S. Crawshaw <sc10003@eng.SAYNOTOSPAMcam.ac.uk>
Viewed: 
545 times
  
On Fri, 17 Sep 1999, Matthew Miller wrote:

Unfortunately, I don't have another rotation sensor, or another slip-clutch,
or a micromotor, so the steering part is less than my ideal, but still
worked out nicely. I used a touch sensor to determine the middle point, and
use a rack-and-pinion design, with the motor connected to a rubber band
(see, here's where the second slip-clutch would have been nicer) which slips
when the extremes are reached.

If you can accept having "discrete" steering positions, then you can use a
touch sensor to mimic a rotation sensor. A line of 1-stud cylindrical
elements moving past a touch sensor will give "0" when the sensor is
exactly between two elements (ie on a whole-stud boundary), and a "1"
anywhere else. So long as you know where you started (eg the middle), you
can just count the pulses to determine where you are.

This may not work at high speeds (easy to miss pulses), but for slow
things like steering it should be fine.

Hope the description is good enough... as ever, no pictures! (I really
must get a digital camera)

Stuart

PS I second the request for a source of slip-clutches - I have lots of
motors (from cheap ZNAP sets!), and don't want to buy the official motor
set just for a single element!



Message has 2 Replies:
  Re: proud of myself (+ some questions)
 
(...) Currently, I've settled for exactly three discrete positions -- left, right, and center. This seems to work well enough for most situations. (25 years ago, 17-Sep-99, to lugnet.robotics)
  Re: proud of myself (+ some questions)
 
(...) in the case you have a spare touch sensor can make a tachometer. Since you always know the direction your steering is running, you can count the teeth and know exactly where it's positioned. It's pretty easy to setup: (URL) Martins [ (...) (25 years ago, 17-Sep-99, to lugnet.robotics)

Message is in Reply To:
  proud of myself (+ some questions)
 
So, I got sent home early from work today, due to the hurricane and all. Good thing because 1) I'd left our windows open 2) Kenmore Square is apparently flooded and it woulda been hard to get home later and, most importantly, 3) I made a cool lego (...) (25 years ago, 17-Sep-99, to lugnet.robotics, lugnet.build)

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