Alt-BEAM Archive
Message #06690
To: beam@sgiblab.sgi.com
From: Richard Piotter richfile@rconnect.com
Date: Tue, 12 Oct 1999 19:41:20 -0500
Subject: [alt-beam] Re: Suspended Microcore?
Tilden's use... Maximum processes.
Wilf Rigter wrote:
>
> Hi Richard,
>
> when you say stay "saturated", do you mean it as Tilden's "maximum number of
> processes" or as in "turned on and hung up"
>
> regards
>
> Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
>
>
> > -----Original Message-----
> > From: Richard Caudle [SMTP:richard@cqc.com]
> > Sent: Tuesday, October 12, 1999 2:30 PM
> > To: beam@sgiblab.sgi.com
> > Subject: Re: Suspended Microcore?
> >
> > I've experimented with suspended tricores with little success. For some
> > reason it would stay saturated when suspended. It would oscillate after
> > grounding resistors.
> >
--
Richard Piotter
richfile@rconnect.com
The Richfiles Robotics & TI web page:
http://richfiles.calc.org
For the BEAM Robotics list:
BEAM Robotics Tek FAQ
http://people.ne.mediaone.net/bushbo/beam/FAQ.html
6691 Tue, 12 Oct 1999 19:47:50 -0500 [alt-beam] Re: What do I Need? - J Wilson's Gearmotors beam@sgiblab.sgi.com Richard Piotter Hey, if anyone ever spots a source for electric utility meters... HOLY
MOLY!!! Some of them are PACKED with snall metal gears. I was looking at
one of hundreds at the Electric Utility Lab at my colege and it had well
over 20-30 gears!!! It even had hard to find METAL right angle gears
useful in making snake bots! SEEK OUT UTILITY POWER METERS!!! (like the
ones that are on the side of your house or at the electric pole or in
your basement).
GREAT if you plan on doing hand made gear boxes!
Mike Kulesza wrote:
>=20
> I was one of the people that bought james Wilson's $5 gear motors. I sc=
rewed
> in and epoxied a long screw to the center of the output gear, and had =
the
> legs attached about 5 - 8 cm form the gear on a thingy that you put in =
a
> wall, it flips open, and you cant pull it back out. (I forgot the name,=
but
> its two halfpipes, attached by a spring, that causes it to open and clo=
se).
> The legs were pressed tightly against a screw to this device. However, =
this
> walker is now scrapped, since the motors were quite weak, were to fast,=
and
> a quite heavy. I measured about 75 rpm @ 5V. The walker could not even =
lift
> its legs. I image that the source of these motors was from some sort of
> recorder...
>=20
> Oh well, this time i used hand made gear motors, made of plexiglass, an=
d
> smaller motors. They have very high torque, and are quite effective. As=
for
> James Wilson's gear motors, they will probably be incorporqated into a
> head...
>=20
> >From: "James Wilson"
> >Reply-To: beam@sgiblab.sgi.com
> >To:
> >Subject: Re: What do I need?
> >Date: Tue, 12 Oct 1999 18:55:30 -0400
> >
> >A while back I came accross some very efficient gear motors and sold s=
ome
> >of
> >them over the list at 5$ cdn each I thought that it was a great deal. =
Many
> >of you complained b/c they did not have an out put shaft, so much for
> >ingenuity!. I have recently had some time to get back into beam and b=
uilt
> >a
> >walker out of them, my mechanics need a little work but one thing to
> >remember is that not a single walker design calls for 360=B0 of rotati=
on for
> >a
> >leg or leg pair. The largest one could possibly utilize is a swing of=
90=B0.
> >But that too is impractical. The optimum is, imho, between 30=B0 and =
60=B0,
> >which my motors will easily accomodate. They turn nearly 180=B0 with =
my
> >current setup, I drilled a hole in the out put gear and screwed the le=
ggs
> >to
> >it. These have built in mechanical stops and heaps and heaps of torqu=
e.
> >The most recent mucking about I have done is with Chiu's Two Motor Wal=
ker
> >and I used 5M resistors in my microcore instead of 1.5M and an LS driv=
er.
> >The walker woked really well, almost to much power! But like I said m=
y
> >mechanics need some work cause the darn thing gets it leggs stuck and =
then
> >just flips it self over and goes into saturation but as with all beam =
stuff
> >I will tweak and triumph. Last night I tried them with the beam ant
> >circuit
> >using an acx for a driver works great! So for those out there that ar=
e
> >willing to tweak I can get more motors the price is the same just let =
me
> >know!
> >
> >James :-))
> >----- Original Message -----
> >From: Senior
> >To:
> >Sent: Monday, October 11, 1999 10:59 PM
> >Subject: Re: What do I need?
> >
> >
> > > Well, you'll have to do a bit of studying and decision making.
> > > Some comments:
> > > 1 - It's hard to get 2 motor walkers to do much, like turning, but
> > > reversing is no problem, and you could most likely tweak it to get =
it to
> > > turn.
> > > 2 - It aint gonna be cheap. Motors that walkers use are extremely h=
ard
> > > to come by and especially when their cheap. You could use servos, w=
hich
> > > are 10 bux a peice, but that right there is 20 dollars, which is ou=
t of
> > > my budget.
> > >
> > > Uh... that's about it.
> > > You could use the traditional walker from:
> > > http://www.golden.net/~amiller/
> > >
> > > Or the bicore walker thing from Ian's site:
> > > http://www.beam-online.com
(it's in there somewhere...)
> > >
> > > And check out the FAQ:
> > > http://people.ne.mediaone.net/bushbo/beam/FAQ.html
> > >
> > > After reading each of those sites carefully, you will know how to b=
uild
> > > a walker! Ta da!
> > >
> > > Happy Beaming,
> > > Kyle
> > >
> > > Chris wrote:
> > > >
> > > > Ok, Here's my deal. Since I'm only 15 and do not have a job I wa=
nt to
> >get the most bang for my buck. I need to know what I need to make a 2
> >motor
> >walker with 4 touch sensors, 2 photodiode eyes, that can go backwards,
> >right, left, forward, is nocturnal. By nocturnal I mean uses a solar =
cell
> >in daytime to charge its batteries when it bicore is off, then at nigh=
t it
> >turns itself on. So I need to know what I need because I don't want t=
o
> >have
> >to pay shipping and handling twice (or more). And I need a site that =
tells
> >me how to hook these things up.
> > > >
> > > > I'm new to all of this BEAM stuff, but I pick things up fairly ea=
sily.
> > > >
> > > > Win a LAPTOP Computer and get your FREE E-mail Account at
> >http://mail.chek.com
> >
>=20
> ______________________________________________________
>
6692 Tue, 12 Oct 1999 19:49:14 -0500 [alt-beam] Re: What do I Need? - J Wilson's Gearmotors beam@sgiblab.sgi.com Richard Piotter Do you have diagrams of your gearbox (or pictures). Also, where/what
type of gears were used. I've got a MASSIVE quantity of plexiglass. a
completely see through bot would be a cool project!
Mike Kulesza wrote:
>=20
> I was one of the people that bought james Wilson's $5 gear motors. I sc=
rewed
> in and epoxied a long screw to the center of the output gear, and had =
the
> legs attached about 5 - 8 cm form the gear on a thingy that you put in =
a
> wall, it flips open, and you cant pull it back out. (I forgot the name,=
but
> its two halfpipes, attached by a spring, that causes it to open and clo=
se).
> The legs were pressed tightly against a screw to this device. However, =
this
> walker is now scrapped, since the motors were quite weak, were to fast,=
and
> a quite heavy. I measured about 75 rpm @ 5V. The walker could not even =
lift
> its legs. I image that the source of these motors was from some sort of
> recorder...
>=20
> Oh well, this time i used hand made gear motors, made of plexiglass, an=
d
> smaller motors. They have very high torque, and are quite effective. As=
for
> James Wilson's gear motors, they will probably be incorporqated into a
> head...
>=20
> >From: "James Wilson"
> >Reply-To: beam@sgiblab.sgi.com
> >To:
> >Subject: Re: What do I need?
> >Date: Tue, 12 Oct 1999 18:55:30 -0400
> >
> >A while back I came accross some very efficient gear motors and sold s=
ome
> >of
> >them over the list at 5$ cdn each I thought that it was a great deal. =
Many
> >of you complained b/c they did not have an out put shaft, so much for
> >ingenuity!. I have recently had some time to get back into beam and b=
uilt
> >a
> >walker out of them, my mechanics need a little work but one thing to
> >remember is that not a single walker design calls for 360=B0 of rotati=
on for
> >a
> >leg or leg pair. The largest one could possibly utilize is a swing of=
90=B0.
> >But that too is impractical. The optimum is, imho, between 30=B0 and =
60=B0,
> >which my motors will easily accomodate. They turn nearly 180=B0 with =
my
> >current setup, I drilled a hole in the out put gear and screwed the le=
ggs
> >to
> >it. These have built in mechanical stops and heaps and heaps of torqu=
e.
> >The most recent mucking about I have done is with Chiu's Two Motor Wal=
ker
> >and I used 5M resistors in my microcore instead of 1.5M and an LS driv=
er.
> >The walker woked really well, almost to much power! But like I said m=
y
> >mechanics need some work cause the darn thing gets it leggs stuck and =
then
> >just flips it self over and goes into saturation but as with all beam =
stuff
> >I will tweak and triumph. Last night I tried them with the beam ant
> >circuit
> >using an acx for a driver works great! So for those out there that ar=
e
> >willing to tweak I can get more motors the price is the same just let =
me
> >know!
> >
> >James :-))
> >----- Original Message -----
> >From: Senior
> >To:
> >Sent: Monday, October 11, 1999 10:59 PM
> >Subject: Re: What do I need?
> >
> >
> > > Well, you'll have to do a bit of studying and decision making.
> > > Some comments:
> > > 1 - It's hard to get 2 motor walkers to do much, like turning, but
> > > reversing is no problem, and you could most likely tweak it to get =
it to
> > > turn.
> > > 2 - It aint gonna be cheap. Motors that walkers use are extremely h=
ard
> > > to come by and especially when their cheap. You could use servos, w=
hich
> > > are 10 bux a peice, but that right there is 20 dollars, which is ou=
t of
> > > my budget.
> > >
> > > Uh... that's about it.
> > > You could use the traditional walker from:
> > > http://www.golden.net/~amiller/
> > >
> > > Or the bicore walker thing from Ian's site:
> > > http://www.beam-online.com
(it's in there somewhere...)
> > >
> > > And check out the FAQ:
> > > http://people.ne.mediaone.net/bushbo/beam/FAQ.html
> > >
> > > After reading each of those sites carefully, you will know how to b=
uild
> > > a walker! Ta da!
> > >
> > > Happy Beaming,
> > > Kyle
> > >
> > > Chris wrote:
> > > >
> > > > Ok, Here's my deal. Since I'm only 15 and do not have a job I wa=
nt to
> >get the most bang for my buck. I need to know what I need to make a 2
> >motor
> >walker with 4 touch sensors, 2 photodiode eyes, that can go backwards,
> >right, left, forward, is nocturnal. By nocturnal I mean uses a solar =
cell
> >in daytime to charge its batteries when it bicore is off, then at nigh=
t it
> >turns itself on. So I need to know what I need because I don't want t=
o
> >have
> >to pay shipping and handling twice (or more). And I need a site that =
tells
> >me how to hook these things up.
> > > >
> > > > I'm new to all of this BEAM stuff, but I pick things up fairly ea=
sily.
> > > >
> > > > Win a LAPTOP Computer and get your FREE E-mail Account at
> >http://mail.chek.com
> >
>=20
> ______________________________________________________
>
6693 Tue, 12 Oct 1999 18:49:18 -0700 [alt-beam] Re: Suspended Microcore? beam@sgiblab.sgi.com Sean Rigter They would be the same circuit but for a HC14 the capacitors must be unequal
with a minimum 1 to 2 ratio.
While this has been discussed before, a reminder of how and why the suspended
bicores work is always a useful exercise (lest we forget).
A HC/HCT240 contains 8 linear inverting buffers and a suspended bicore made
with this chip using equal value capacitors has voltage waveforms which show
that after each output transistion, the voltage across the "suspended"
resistor is equal to the power supply voltage ( +V) meaning one side is 0V and
the other is +V.
The voltage across the resistor then decays towards 0V meaning the voltage at
each end is decaying towards 1/2 of +V.
When the voltage at the input of the inverter crosses the switching threshold,
the inverter will switch and the bicore outputs "flip" state with process
repeating itself.
So for a 74HC240 this occurs near 1/2 of +V (at 5V they are 2V positive going
and 3V negative going) and for a 74HCT240 they occurs at 1V and 2V
respectively. No problem since the waveform eventually passes though the
threshold before reaching +V/2. It does however mean that the lower threshold
voltage is reached earlier in a HCT240 than in a HC240 which is why the
frequency of a HCT240 is always higher than a HC240 for the same RC values.
A 74HC14 contains 6 Schmitt Trigger invereters with hysteresis which means the
input thresholds are greater than +V/2 going in either direction (at 5V they
are 3V positive going and 2V negative going). This means the waveforms at the
inputs of a HC14 suspended bicore with equal capacitors decays towards +V/2
as the terminal voltage and will never cross the switching thresholds and so
that circuit does not oscillate.
When unequal values ie 0.1 and 0.33 of capacitors are used, the voltage at the
end of the resistor with the smaller value capacitor will rise much faster
than the other end and the terminal voltage will cross through +V/2 and
continue towards terminal voltages of 3/4 or 1/4 of +V ( rising or falling)
and therefore crosses though the Schmitt trigger thresholds. This scenario
holds for a 74HC14 and I haven't had a chance to try this with a 74HCT14 but
the switching thresholds for that device are 0.8V and 2V and therefore that
chip will probably work at +5V supply with equal capacitors as well.
Sorry for the nitty gritty but that is what goes on under the hood of a
suspended bicore and explains it's behaviour. For more details check out
Wouter Brok's formal paper on bicore operation at
BEAM Online - http://www.beam-online.com
Iv Clarence Harper wrote:
> Ok, so how does a bicore built with a 74HC240 differ from one built with a
> 74HC14?
>
> -Clarence
> ~~~~~
> Never before has so much silliness passed as serious business.
> ~~~~~
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