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Subject: 
Re: Tilt
Newsgroups: 
lugnet.robotics
Date: 
Wed, 1 Dec 1999 19:40:47 GMT
Viewed: 
428 times
  
  I'm surprised no one has mentioned this one yet.  This is a way to get two
axis tilt sensors.  It is basically tilted or not, no graduating scale, but,
see below later...

Get an old Bic ball-point pen.  Cut two cylinders to some arbitrary length.
Bend them by heating them up and bending until the proper angle for the tilt
trigger is reached.  in either end of the tubes drill two tiny holes such that
wires can be inserted that are parallel to each other and fairly close
together.  Insert a BB, ball bearing, whatever into the tubes, then insert the
wires into their holes so that the BB will touch both wires when it rest
against them.  Make one of each of these pairs of wires common, attach 4
resistors of different values to the other wire of each pair.  Choose the
resistor values so that when they are "chorded" you can get unique values for
all possible combinations of tilts, there aren't that many: tilted forward
and/or left or right or backward and/or left or right.

Connect the other side of all of the resistors together.  You now have a
sort-of four-way touch switch that is a passive sensor.  Now mount the two
tubes perpendicular to each other and connect the wires to your electrical
plate for the RCX.  Voila!  A simple (cheap!) tilt sensor.

ALTERNATIVE

This alternative one will get you a graduated (with lots of hysteresis
unfortunately) tilt sensor.

Get a small potentiometer (pot) with a long enough shaft that you can drill a
hole perpendicular to the shaft for a piece of piano wire.  Get a heavy lead
fishing weight and mount it to the end of the short piano wire piece.  Mount
the whole shebang such that the pot will rotate when you are tilting in the
direction you want to measure.  This will have to be a single sensor direction
for a single sensor input, but it will be a mostly linear travel that will
sense the actual angle of the tilt.  Oh, obviously the lead weight is below the
pot shaft and perpendicular to the horizontal axis.

This is again a passive sensor.

have fun,
DLC



Message is in Reply To:
  RE: Tilt
 
The rotation sensor does seem like a very good way to go. The only real problem is you can only detect tilt on one plane (front to back, or side to side, not both) Unless, of course, you have two rotation sensors. (I didn't even bother ordering just (...) (25 years ago, 1-Dec-99, to lugnet.robotics)

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