Subject:
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Re: Tilt
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 2 Dec 1999 04:12:53 GMT
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Viewed:
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609 times
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I tested the touch sensor approach...I think it will take too much weight/force
to trigger the touch sensor.
I'm now working on using the Mindstorms light sensor as a tilt sensor. I hung a
freely swinging brick flush against the light sensor. As the tilt angle
increases, the brick swings away from the light sensor, reducing the amount of
light reflected back. If ambient light were blocked out, it might be accurate
enough to give angle and/or acceleration. I'm not sure what to do about the
brick swinging back and forth when the robot decelerates or reverses direction.
In lugnet.robotics, Steve Hassenplug <SteveH@mailcode.com> writes:
> 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 one. I went right for two)
>
> With the rotation sensor, you can detect the angle of tilt and calculate the
> speed of tilt (ignoring sudden changes, like acceleration, to calculate
> tilt). OR you could make an accelerometer to measure the speed by measuring
> the tilt angle.
>
> Now that would be a complex device & program... sounds like a challenge...
>
> One problem with the plum bob is getting enough weight to push a touch
> sensor. That shouldn't be a problem with the rotation sensors.
>
> </steve>
>
> -----Original Message-----
> From: Jim West [mailto:Jim@jameswest.com]
> Sent: Wednesday, December 01, 1999 9:47 AM
> To: lego-robotics@crynwr.com
> Subject: RE: Tilt
>
> Ok, here's another idea.
>
> I just ordered my first rotation sensor...and note that I do not know the
> details of this sensor yet.
>
> Would it be possible to attach a pendulum to the rotation sensor and use it
> to measure the amount of angle?
>
> If so, you wouldn't need a switch.
>
> Ok...just thinking out loud again... :)
>
>
>
> At 07:24 AM 12/01/1999 -0700, Jim West wrote:
> > At 09:08 AM 12/01/1999 -0500, Steve Hassenplug wrote:
> > > Another solution for detecting tilt would be the kind of tilt device used • in
> > > old pinball machines (I don't know if it's still used). I'm not sure how • to
> > > explain it, but I can give you a similar example:
> >
> >
> > As one who collects pinball machines (I have 10 now), you are refering
> > to a plumb-bob tilt mechanism that is in use on the newer pins.
> >
> >
> > > Hold a pencil at the end between your index finger and thumb, so the • pencil
> > > hangs down (and can swing a bit). Now take your other hand and make a
> > > circle with your index finger and thumb. Hold this around the pencil near
> > > the bottom. If your hands were connected together, you could detect when
> > > they 'tilted' by detecting when the pencil touches your bottom hand.
> > >
> > > If you turn the pencil into a metal rod, and your bottom hand into a metal
> > > ring, and attach wires to both, you have a simple switch to detect tilt
> > > (with some other hardware connecting the two).
> >
> > Right. There is a metal rod to which the plumb-bob is attached (a
> > solid metal cone shaped item) and a metal ring. You can adjust the
> > height of the plumb-bob with relation to the ring to change the
> > sensitivity of the "tilt". BTW, the plumb-bob is inverted, i.e. the
> > point sticks down. The lower the plumb-bob the less gap between the ring
> > and the plumb-bob and thus more sensitive to tilt.
> >
> >
> > > This would eliminate the need to use some pesky toxic chemical, and should
> > > be fairly easy to implement using mostly lego parts.
> > >
> > > If you want, the pendulum could be replaced with one that moves on a • single
> > > plane and pushes a touch switch when it tilts (one switch for each • direction
> > > you want to detect)
> > >
> > > I hope this makes sense.
> >
> > On the pins from the 80's the tilt device was a pinball on a track
> > mounted to the side of the cabinet. This track was mounted at an angle
> > so that the steel ball would sit at one end. At the other end of this
> > track is a "roll over" switch. If the pin was either shoved too hard or
> > lifted up from the front the ball would roll to the other end of this
> > track, roll over the switch and BAM!, you'd get a tilt.
> >
> > I would think that this approach would actually work a bit better. Use
> > a marble that is heavy enough to engage a touch sensor and build a track
> > that the marble/steel ball can ride in/on with the touch sensor at the
> > other end.
> >
> > The real problem with the plumb-bob tilt (from my experience with my
> > pins) is that too much jostling (sp) would cause the plumb-bob to hit the • ring.
> >
> > If the pendulum one moved in a single plane, you'd want to make sure
> > that the movement of the bot wouldn't cause an "erroneous" tilt.
> >
> >
> >
> > > </steve>
> >
> >
> > Jim West
> > NIC Team Lead
> > NIC Oracle Developer and DBA in Training
> > NIC Chief Cook and Bottle Washer
> > MCI Worldcom
>
> Jim West
> LEGO@jameswest.com
> LUGNET Member 63
> LEGO Rulez!
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Message has 1 Reply:
 | | Re: Tilt
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| (...) [snip] (...) direction. What about inverting the problem? You could have a vertical shaft with a weight at the top, and some sort of resistance at the bottom (rubber bands? elastic strips?). Something like this: _____ | | | | <- weight ----- | (...) (25 years ago, 2-Dec-99, to lugnet.robotics)
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Message is in Reply To:
| | RE: Tilt
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| 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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