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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Wed, 1 Dec 1999 16:06:36 GMT
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Original-From:
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Rich Thompson <RICH_THOMPSON@CMCMAX.ihatespamCOM>
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Viewed:
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685 times
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The halobot I built uses a pure lego mechanism that does a similar trick
with a rotation sensor (http://www.marsrobot.com/halobot/halobot.htm). I use
it for bump detection, but it would be serviceable as a tilt sensor. It
takes a pretty good "tilt" to register the rotation sensor in a standard
rotation sensor setup in NQC SetSensorMode(SENSOR_2,SENSOR_MODE_ROTATION);.
With that setting a good bump will only register a change from 0 to 1.
Changing the sensor mode to SetSensorMode(SENSOR_2,SENSOR_MODE_RAW); in NQC
will show a greater delta for change (1024 to 560 I think) but it still does
not give finer measurement due to the limitations of the rotations sensor
(someone correct me if I am wrong).
Rich Thompson
http://www.marsrobot.com
-----Original Message-----
From: news-gateway@lugnet.com [mailto:news-gateway@lugnet.com]On Behalf
Of Wes Matchett
Sent: Wednesday, December 01, 1999 9:13 AM
To: lego-robotics@crynwr.com
Subject: Re: Tilt
I was considering the same thing; there are a few advantages of using
rotation
sensors:
- They would measure all degrees of tilt, but any circuit interrupted type
(touch sensor, rod & ring, etc.) will only sense a single angle.
- They could sense how quickly a change in tilt is occurring.
One disadvantage is they have a slight resistance to turning, so the sensor
may
not measure fine degrees of change, or the pendulum would require enough
weight
to overcome this resistance to measure slight angles. In reality this may
be a
non-issue.
-Wes
Jim West wrote:
>
> 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 is in Reply To:
 | | Re: Tilt
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| I was considering the same thing; there are a few advantages of using rotation sensors: - They would measure all degrees of tilt, but any circuit interrupted type (touch sensor, rod & ring, etc.) will only sense a single angle. - They could sense (...) (25 years ago, 1-Dec-99, to lugnet.robotics)
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