Sorry, make that "half a dozen".

Alan  KM6VV

> Cross posted to HBRobotics
>
> That gives ME an idea.  I've been considering various new ways we can run
> our micromouse 'bots in the maze, and as I don't have a half roomba 'bots
> laying around, why not micromice!
<snip?

I wasn't thinking so much of using less acceleration/deceleration, but
rather just breaking up the moves into small moves.  I suppose one could
actually change the distance between each of the steps, or the speed of each
of the steps to also control.

Good ideas!

Alan KM6VV

> -----Original Message-----
> On Behalf Of oric_dan
>
> --- In SeattleRobotics@yahoogroups.com, "Alan Marconett" <KM6VV@...>
> wrote:
> >
> > Going back to David's original comment (I think), then the intent of
> > reducing the refresh rate to the R/C servos is to soften the movements
> by> lowering their torque?
> >
> > Can't you break up the move into a series of smaller moves? Or is this
> done> for another reason?
> >
> > Alan  KM6VV
> >
>
>
> Yeah, with lower servo-torque, the joints will bend more when the feet hit
> the ground.
>
> I guess what you mean by smaller movements is to use
> acceleration/deceleration control on the servos. Then the feet wouldn't
> bang into the ground so hard. I've done this too, and it's pretty cool.
>
> What we were really talking about were different ways to add mechanical
> compliance to the frame. This could probably benefit from a number of
> approaches: (a) less rigid frame, (b) spring-loaded joints, (c) more
> compliance in servos, &etc.
>
> Item (c) is a lot easier for a guy like me to implement than item (b).
> Also, it gives you the ability to change the torque at different times in
> the step - eg, lesser during foot-fall, greater during push-off.
>
>
>
> >
> > > -----Original Message-----
> > > On Behalf Of oric_dan
> > >
> > > Update to this. This morning, I dug out my old servo controller that>
> > allows the update period to be set as long as 50-msec, and tested it
> with> > a Hitec HS-322HD servo. For the slow updates, the torque on the
> servo> > horns does indeed lessen significantly [using the finger horn-
> twisting> > test]. For normal 20-msec updates, the the servo horn much
> more firmly, as> > should be.
> > >
> >
>
>
>
>
> ------------------------------------
>
> Visit the SRS Website at http://www.seattlerobotics.orgYahoo! Groups Links
>
>
>

Cross posted to HBRobotics

That gives ME an idea.  I've been considering various new ways we can run
our micromouse 'bots in the maze, and as I don't have a half roomba 'bots
laying around, why not micromice!

As I'd never played the game, I looked up the rules:

http://www.pacman-plus.com/rules.htm

Would the ghosts be programmed like a "swarm"?

Seems like an interesting exercise.

Thanks Don!

Alan  KM6VV

> -----Original Message-----
> On Behalf Of don clay
>
> Here's something that I posted on FRR, but it might work for a new
> competition
> for Robothon albeit on a smaller scale.   It could be run just like a
> pacman game,
> with the highest points the winner.
>
> http://www.dailycamera.com/news/ci_13759021
>

What everyone else said is correct, but I'll add one more detail: Even
if it was possible to make it work, to get a capacity even remotely
comparable to what a $100 UPS will give you, you would likely spend
far more on caps.

That said, there is one possibility, though I don't think it's a good
idea. Computer equipment operates on DC, so it is possible that you
could add caps on the DC side of your NAS and improve your power
somewhat. However your NAS almost certainly cost more than a UPS, and
the likelihood of destroying it and possibly your data when you modify
it is high enough that it really isn't worth saving /maybe/ $50 by the
time you buy the high capacity caps and everything.

Besides, if all you want to do is stabilize your voltage, not provide
battery backup, there are cheaper solutions. Amazon sells a varietty
of voltage regulators for as little as $25:
<http://www.amazon.com/s/ref=nb_ss?url=search-alias%3Daps&field-keywords=voltage\
+regulator&x=0&y=0>.
Those won't help you if your power drops way down (or if it goes out
completely), but will stabilize it from normal fluctuations.

On Wed, Nov 11, 2009 at 1:38 AM, megablasto2000
<megablasto2000@...> wrote:
> Hi all,
>
> I just joined the group to ask a question about home AC power.  I'm fairly
electronics ignorant, but good at following instructions and not afraid to try
things.
>
> Where I am at, I frequently have mild brown outs.  Nothing real serious, but
still...I was wondering if it is possible to use some inexpensive capacitors to
stabilize incoming power to a NAS (Network Attached Storage) PC in my house.  I
was thinking of just soldering the proper capacitors to a power cable and that
this might be a cheap easy solution to keep the storage PC from having to deal
with voltage fluctuations.  I know people do something like this for their cars
when they add a bunch of stereo equipment to it.
>
> Of course a better solution would be to get a UPS or line conditioner, but if
I was going to buy one of those, I would only want to get a good one that is at
least $100 and up, esp power conditioners.  But I figured just soldering up a
few power cables with some capacitors would be a possible solution to keeping
the voltage more stable for my storage PC without putting investment into a UPS
or power conditioner for now.
>
> Side questions:
>
> 1.)  If I add capacitors to a cable, does that turn it into D/C power, or is
it still A/C? Because the power supply on the PC accepts only AC and then
converts to D/C for the components inside.
>
> 2.)  What type and value capacitors would I get for such application,
(assuming it's doable)?
>
> Thank you,
> Ken Bagwell
>
>
>
> ------------------------------------
>
> Visit the SRS Website at http://www.seattlerobotics.orgYahoo! Groups Links
>
>
>
>

On Wed, 11 Nov 2009 10:10:58 -0800, "Alan Marconett"
<KM6VV@...> wrote:

>Going back to David's original comment (I think), then the intent of
>reducing the refresh rate to the R/C servos is to soften the movements by
>lowering their torque?
>
>Can't you break up the move into a series of smaller moves? Or is this done
>for another reason?

Or you could just use a smarter servo. Bioloid servos (AX, DX, and RX
series) all have compliance parameters that can be adjusted "on the
fly" to accomplish this sort of thing in a supported manner.

Later,
Jon

--- In SeattleRobotics@yahoogroups.com, "Alan Marconett" <KM6VV@...> wrote:
>
> Going back to David's original comment (I think), then the intent of
> reducing the refresh rate to the R/C servos is to soften the movements by>
lowering their torque?
>
> Can't you break up the move into a series of smaller moves? Or is this done>
for another reason?
>
> Alan  KM6VV
>


Yeah, with lower servo-torque, the joints will bend more when the feet hit the
ground.

I guess what you mean by smaller movements is to use acceleration/deceleration
control on the servos. Then the feet wouldn't bang into the ground so hard. I've
done this too, and it's pretty cool.

What we were really talking about were different ways to add mechanical
compliance to the frame. This could probably benefit from a number of
approaches: (a) less rigid frame, (b) spring-loaded joints, (c) more compliance
in servos, &etc.

Item (c) is a lot easier for a guy like me to implement than item (b). Also, it
gives you the ability to change the torque at different times in the step - eg,
lesser during foot-fall, greater during push-off.



>
> > -----Original Message-----
> > On Behalf Of oric_dan
> >
> > Update to this. This morning, I dug out my old servo controller that> >
allows the update period to be set as long as 50-msec, and tested it with> > a
Hitec HS-322HD servo. For the slow updates, the torque on the servo> > horns
does indeed lessen significantly [using the finger horn-twisting> > test]. For
normal 20-msec updates, the the servo horn much more firmly, as> > should be.
> >
>

Here's something that I posted on FRR, but it might work for a new competition
for Robothon albeit on a smaller scale.   It could be run just like a pacman
game,
with the highest points the winner.

http://www.dailycamera.com/news/ci_13759021

Going back to David's original comment (I think), then the intent of
reducing the refresh rate to the R/C servos is to soften the movements by
lowering their torque?

Can't you break up the move into a series of smaller moves? Or is this done
for another reason?

Alan  KM6VV

> -----Original Message-----
> On Behalf Of oric_dan
>
> Update to this. This morning, I dug out my old servo controller that
> allows the update period to be set as long as 50-msec, and tested it with
> a Hitec HS-322HD servo. For the slow updates, the torque on the servo
> horns does indeed lessen significantly [using the finger horn-twisting
> test]. For normal 20-msec updates, the the servo horn much more firmly, as
> should be.
>

I've used pretty much all of the servos, they all suffer the same from
slow or missing pulses.  I hear that the digitals do not, they retain
their pulse value even when sporadic or missing.  However, I have not
tested this yet...

DLC

> --- In SeattleRobotics@yahoogroups.com, "oric_dan" <oric_dan@...> wrote:
>>
>> -- In SeattleRobotics@yahoogroups.com, "David Buckley" <david@> wrote:
>> >
>
>> >
>> > >Not just slows down, but without a pulse coming in every 20-msec, the
>> servo loops don't maintain full torque, so the compliance with
>> >regards to external forces increases significantly.
>> >
>> > Yes I took that for granted, but it is very servo dependant, The Hitec
>> servos generally are much better for this than the GWS except the S06
>> is better than the high torque standard sized Hitec.
>> >
>>
>>
>> Hmm, I did this 3 or 4 years ago, and was not using Hitec servos at the
>> time. Probably some old Futaba servo. Now I only use Hitecs anymore, so
>> maybe they hold the torque better.
>>
>> OTOH, I don't quite see why they would. Assuming all analog servos work
>> similarly, and based on internal measurements I took also a few years
>> ago, the servo motors internally are activated briefly, only when there
>> is a pulse on the external signal line (call it +E pulse on the yellow
>> wire).
>>
>> Then, for each +E pulse, the motor itself gets a current pulse of
>> between 2 and about 7 or 8 msec length, with the length dependent upon
>> the torque on the servo horn. [if you try to send pulses too fast, eg <
>> 10-msec, the servo loop gets screwed andthe servo vcan lock up].
>> However, when the time between +E pulses is long, the motor activation
>> duty-cycle goes way down, so the overall holding torque should also go
>> down.
>>
>> Maybe it's just a matter of using a properly long interval between +E
>> pulses, to see the effect, and this is servo-dependent. Ie, maybe the
>> Hitecs will show eventually it for pulse intervals > 50-msec.
>>
>
>
> Update to this. This morning, I dug out my old servo controller that
> allows the update period to be set as long as 50-msec, and tested it with
> a Hitec HS-322HD servo. For the slow updates, the torque on the servo
> horns does indeed lessen significantly [using the finger horn-twisting
> test]. For normal 20-msec updates, the the servo horn much more firmly, as
> should be.
>
>
>
>
>
>
> ------------------------------------
>
> Visit the SRS Website at http://www.seattlerobotics.orgYahoo! Groups Links
>
>
>
>


--
Dennis Clark
TTT Enterprises

--- In SeattleRobotics@yahoogroups.com, ed@... wrote:
>
> Ken,
>
> Attaching a capacitor across the AC mains will only result in a large> spark
at the plug and a big bang from the capacitor as it explodes when> you plug in
the cable.  Capacitors store a DC charge like batteries, they> are a dead short
to AC (for all practical >purposes surrounding this use> case).
>


Ken, speaking from direct experience .... back in the early days of electronics,
when I was a newly minted ham operator, I was using the heavy-duty power supply
from an old TV set to power my rig. Those things could probably put out
1000-watts, or something like that.

In those days, the vacuum tubes were always going bad [think, heat kills]. As it
turns out, the main rectifer tube [think, diode] shorted out, and proceeded to
glow red-hot in intensity. Before I could turn off the switch, the large
metal-jacket filter capacitor, probably 6" tall,  blew up and flew up and put a
dent in the ceiling, and filled the room with a lot of what was probably toxic
smoke. Capacitors don't like direct AC, as Ed says, "dead short to AC".

So, this is what to expect if you put capacitors straight across AC power lines.

--- In SeattleRobotics@yahoogroups.com, "oric_dan" <oric_dan@...> wrote:
>
> -- In SeattleRobotics@yahoogroups.com, "David Buckley" <david@> wrote:
> >

> >
> > >Not just slows down, but without a pulse coming in every 20-msec, the servo
loops don't maintain full torque, so the compliance with >regards to external
forces increases significantly.
> >
> > Yes I took that for granted, but it is very servo dependant, The Hitec
servos generally are much better for this than the GWS except the S06 is better
than the high torque standard sized Hitec.
> >
>
>
> Hmm, I did this 3 or 4 years ago, and was not using Hitec servos at the time.
Probably some old Futaba servo. Now I only use Hitecs anymore, so maybe they
hold the torque better.
>
> OTOH, I don't quite see why they would. Assuming all analog servos work
similarly, and based on internal measurements I took also a few years ago, the
servo motors internally are activated briefly, only when there is a pulse on the
external signal line (call it +E pulse on the yellow wire).
>
> Then, for each +E pulse, the motor itself gets a current pulse of between 2
and about 7 or 8 msec length, with the length dependent upon the torque on the
servo horn. [if you try to send pulses too fast, eg < 10-msec, the servo loop
gets screwed andthe servo vcan lock up]. However, when the time between +E
pulses is long, the motor activation duty-cycle goes way down, so the overall
holding torque should also go down.
>
> Maybe it's just a matter of using a properly long interval between +E pulses,
to see the effect, and this is servo-dependent. Ie, maybe the Hitecs will show
eventually it for pulse intervals > 50-msec.
>


Update to this. This morning, I dug out my old servo controller that allows the
update period to be set as long as 50-msec, and tested it with a Hitec HS-322HD
servo. For the slow updates, the torque on the servo horns does indeed lessen
significantly [using the finger horn-twisting test]. For normal 20-msec updates,
the the servo horn much more firmly, as should be.

Ken,

   Power line conditioning is way more difficult than adding caps.  The
short answer to your question is : No, that won't work.  The UPS is
pretty much your best, and perhaps only solution to your problem.

DLC

> Hi all,
>
> I just joined the group to ask a question about home AC power.  I'm fairly
> electronics ignorant, but good at following instructions and not afraid to
> try things.
>
> Where I am at, I frequently have mild brown outs.  Nothing real serious,
> but still...I was wondering if it is possible to use some inexpensive
> capacitors to stabilize incoming power to a NAS (Network Attached Storage)
> PC in my house.  I was thinking of just soldering the proper capacitors to
> a power cable and that this might be a cheap easy solution to keep the
> storage PC from having to deal with voltage fluctuations.  I know people
> do something like this for their cars when they add a bunch of stereo
> equipment to it.
>
> Of course a better solution would be to get a UPS or line conditioner, but
> if I was going to buy one of those, I would only want to get a good one
> that is at least $100 and up, esp power conditioners.  But I figured just
> soldering up a few power cables with some capacitors would be a possible
> solution to keeping the voltage more stable for my storage PC without
> putting investment into a UPS or power conditioner for now.
>
> Side questions:
>
> 1.)  If I add capacitors to a cable, does that turn it into D/C power, or
> is it still A/C? Because the power supply on the PC accepts only AC and
> then converts to D/C for the components inside.
>
> 2.)  What type and value capacitors would I get for such application,
> (assuming it's doable)?
>
> Thank you,
> Ken Bagwell
>
>
>
> ------------------------------------
>
> Visit the SRS Website at http://www.seattlerobotics.orgYahoo! Groups Links
>
>
>
>


--
Dennis Clark
TTT Enterprises

Ken,

Attaching a capacitor across the AC mains will only result in a large
spark at the plug and a big bang from the capacitor as it explodes when
you plug in the cable.  Capacitors store a DC charge like batteries, they
are a dead short to AC (for all practical purposes surrounding this use
case).  Spend the money on a UPS, they are well worth the money, and
cheaper than rebuilding your house after a fire caused by exploding
capacitors.

Ed Okerson


> Hi all,
>
> I just joined the group to ask a question about home AC power.  I'm fairly
> electronics ignorant, but good at following instructions and not afraid to
> try things.
>
> Where I am at, I frequently have mild brown outs.  Nothing real serious,
> but still...I was wondering if it is possible to use some inexpensive
> capacitors to stabilize incoming power to a NAS (Network Attached Storage)
> PC in my house.  I was thinking of just soldering the proper capacitors to
> a power cable and that this might be a cheap easy solution to keep the
> storage PC from having to deal with voltage fluctuations.  I know people
> do something like this for their cars when they add a bunch of stereo
> equipment to it.
>
> Of course a better solution would be to get a UPS or line conditioner, but
> if I was going to buy one of those, I would only want to get a good one
> that is at least $100 and up, esp power conditioners.  But I figured just
> soldering up a few power cables with some capacitors would be a possible
> solution to keeping the voltage more stable for my storage PC without
> putting investment into a UPS or power conditioner for now.
>
> Side questions:
>
> 1.)  If I add capacitors to a cable, does that turn it into D/C power, or
> is it still A/C? Because the power supply on the PC accepts only AC and
> then converts to D/C for the components inside.
>
> 2.)  What type and value capacitors would I get for such application,
> (assuming it's doable)?
>
> Thank you,
> Ken Bagwell
>
>
>
> ------------------------------------
>
> Visit the SRS Website at http://www.seattlerobotics.orgYahoo! Groups Links
>
>
>

Ken,

The caps won't get you through a brown out of any length.  Only a UPS will do
that.

If you wanted to protect the input supply for glitches and surges, you'd be
better
off using a power strip with surge protection.  Those have transorbs & (I'm
going
to massacree this word so someone should correct me) varistors in them which
are designed to protect your ac from nasty shtuff the power company & mother
nature send your way.

A UPS is your best bet.  I've taken some nasty hits over the past almost 10
years
with the UPS's that I have installed and survived (knock on wood).

As you probably know, the length of time that a UPS will keep you up is directly
proportional to the amount of money that you spend on them.

don clay

From: Ken Bagwell
> Hi all,
>
> I just joined the group to ask a question about home AC power.  I'm
> fairly electronics ignorant, but good at following instructions and
> not afraid to try things.
>
> Where I am at, I frequently have mild brown outs.  Nothing real
> serious, but still...I was wondering if it is possible to use some
> inexpensive capacitors to stabilize incoming power to a NAS (Network
> Attached Storage) PC in my house.  I was thinking of just soldering
> the proper capacitors to a power cable and that this might be a cheap
> easy solution to keep the storage PC from having to deal with voltage
> fluctuations.  I know people do something like this for their cars
> when they add a bunch of stereo equipment to it.
>
> Of course a better solution would be to get a UPS or line conditioner,
> but if I was going to buy one of those, I would only want to get a
> good one that is at least $100 and up, esp power conditioners.  But I
> figured just soldering up a few power cables with some capacitors
> would be a possible solution to keeping the voltage more stable for my
> storage PC without putting investment into a UPS or power conditioner
> for now.
>
> Side questions:
>
> 1.)  If I add capacitors to a cable, does that turn it into D/C power,
> or is it still A/C? Because the power supply on the PC accepts only AC
> and then converts to D/C for the components inside.
>
> 2.)  What type and value capacitors would I get for such application,
> (assuming it's doable)?
>
> Thank you,
> Ken Bagwell
>
>

Hi all,

I just joined the group to ask a question about home AC power.  I'm fairly
electronics ignorant, but good at following instructions and not afraid to try
things.

Where I am at, I frequently have mild brown outs.  Nothing real serious, but
still...I was wondering if it is possible to use some inexpensive capacitors to
stabilize incoming power to a NAS (Network Attached Storage) PC in my house.  I
was thinking of just soldering the proper capacitors to a power cable and that
this might be a cheap easy solution to keep the storage PC from having to deal
with voltage fluctuations.  I know people do something like this for their cars
when they add a bunch of stereo equipment to it.

Of course a better solution would be to get a UPS or line conditioner, but if I
was going to buy one of those, I would only want to get a good one that is at
least $100 and up, esp power conditioners.  But I figured just soldering up a
few power cables with some capacitors would be a possible solution to keeping
the voltage more stable for my storage PC without putting investment into a UPS
or power conditioner for now.

Side questions:

1.)  If I add capacitors to a cable, does that turn it into D/C power, or is it
still A/C? Because the power supply on the PC accepts only AC and then converts
to D/C for the components inside.

2.)  What type and value capacitors would I get for such application, (assuming
it's doable)?

Thank you,
Ken Bagwell

-- In SeattleRobotics@yahoogroups.com, "David Buckley" <david@...> wrote:
>
> > Bar-Circle-Cyc-Bar [supposed to be Cyc in a circle with a bar through it].
> What????
>


LOL. I meant Cyc as in Lenat's CYC, and was basically thrashing the idea of
handcoding every factoid and algorithm.


>
> >Not just slows down, but without a pulse coming in every 20-msec, the servo
loops don't maintain full torque, so the compliance with >regards to external
forces increases significantly.
>
> Yes I took that for granted, but it is very servo dependant, The Hitec servos
generally are much better for this than the GWS except the S06 is better than
the high torque standard sized Hitec.
>


Hmm, I did this 3 or 4 years ago, and was not using Hitec servos at the time.
Probably some old Futaba servo. Now I only use Hitecs anymore, so maybe they
hold the torque better.

OTOH, I don't quite see why they would. Assuming all analog servos work
similarly, and based on internal measurements I took also a few years ago, the
servo motors internally are activated briefly, only when there is a pulse on the
external signal line (call it +E pulse on the yellow wire).

Then, for each +E pulse, the motor itself gets a current pulse of between 2 and
about 7 or 8 msec length, with the length dependent upon the torque on the servo
horn. [if you try to send pulses too fast, eg < 10-msec, the servo loop gets
screwed andthe servo vcan lock up]. However, when the time between +E pulses is
long, the motor activation duty-cycle goes way down, so the overall holding
torque should also go down.

Maybe it's just a matter of using a properly long interval between +E pulses, to
see the effect, and this is servo-dependent. Ie, maybe the Hitecs will show
eventually it for pulse intervals > 50-msec.



>
> >When I was trying to make my hexapod Nico-6 go fast, I was churning the
servos at about 2X the rate shown in your youtube video
> >[ie, max velocity], and also made the legs+strides much longer. This caused
extreme bashing of the feet during the footfalls. This is why I >am thinking
that having a somewhat slippery "heels" in the feet [plus compliant frame] would
help. OTOH, as mentioned, the "toe ends" >would have high friction for stepping
off. Bipartate friciton-foot.
>
> Hextor when in tripod gait has a light pause between each stride due to the
program swopping between tripods which means the forward movement isn't
continuous hence the jerkyness. In animals I guess due to the compliance there
is a gradual changeover from one foot to another which eliminates the jerky
forward motion or at least converts the energy somewhere.
>


There are large deceleration forces acting on the feet when they hit the ground,
and these forces are absorbed by the leg-joints bending and the muscles and
tendons storing energy like elastic springs, and which energy is recovered and
reused during the pushoff into the subsequent step. According to my notes, the
following paper says energy recovery is as high as 70% in animals. More
important, the higher the gait speed.

R.J. Full and C.T. Farley, "Musculoskeletal Dynamics in Rhythmic Systems: a
Comparative Approach to Legged Locomotion", in Biomechanics and Neurocontrol of
Posture, Springer (2000).

Of course, in my robots, this sort of energy absorption/recovery is essentially
zero, so the frame goes jerly and unstable.


>
> >> Grush isn't radical just realistic. If the sensory/actuation delays in
humans are ~400ms then we have to use some other mechanism to
> >> get the 70ms control rate observed (Grush - 1997 The Architecture of
Representation=arch-text.htm <14>) so it looks as if we know >>what the goal
values are before we make a move.
> >Or predict what they should be.
>
> Yes we plug some values into the feedback loops
>


Ie, into the motor emulator circuits.


>
> >As I see it, lookup is close to how the cerebellum works. It is a huge timing
machine controlling millions of muscle fibers temporally and >in parallel, and
the timing is largely learned via practice.
> >It's a little difficult to imagine the brain would have the power to compute
IK or diff-eqs for the many millions of muscle fibers involved in >every single
movement. Too many DOFs.
>
> That seems spot on to me.
>
> David
>


I like to think of the example of a pitcher throwing a baseball. It might be
doable to write a single diff-eq for the ball itself flying from the pitcher to
the home plate and going through some complex evil-looking gyrations, but for
the pitcher himself, you'd have to write one involving every single joint and
muscle fiber in his body - ie, 10s of millions, nonlinear and highly-coupled.
It's just unrealistic.

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--- In SeattleRobotics@yahoogroups.com, Lamis Abdo <lamis_abdo@...> wrote:
>


You might not get more than general ideas from the combination lock pages. Look
at pages regarding general logic design too. What you really need to do is
design a simple logic circuit that follows the user requirements specified for
the project, and which produces the enable/inputA/inputB signals for the L293.

Your instructor should have either covered the basics of logic design in the
lectures, or else required a prerequisite course in logic. I don't see how
anyone could be realistically expected to do the project without this.

Also, in this day and age, I would think almost anyone in the real-world would
implement such a lock using a small microcontroller, rather than discrete logic.
Much easier to develop+change software than rewire hardware.




>
> Hello Dan. Thank you for taking the time to read my message. I do appreciate
your assistance very much . I've downloaded the datasheet for the L293B and I
will check the links you have sent me hope I can find some useful hints.
> I'll try to do my best, after all "answers just don't come simply"
>
> I hope that you will have the time in the future to help me whenever I needed
help.
>
> Best Regards.
> Lamis Abdo
>
>  
>
>
>
> ________________________________
> From: oric_dan <oric_dan@...>
> To: SeattleRobotics@yahoogroups.com
> Sent: Mon, November 9, 2009 10:38:38 PM
> Subject: [SeattleRobotics] Re: Need help designing a sequential password for a
DC motor
>
>  
> --- In SeattleRobotics@ yahoogroups. com, Lamis Abdo <lamis_abdo@ ...> wrote:
> >
>
> Hello Lamis. This is a simple problem for someone in an EE program, and who
has taken a basic course in logic. Sounds like you are neither. I am surprised
that 25 other people on this forum have not responded. Probably no one wants to
simply "give you the answer". After all, it's a design course. You're in school.
>
> First, follow up on simple combination locks using google.
>
> http://www.discover circuits. com/E/elec- lock.htm
>
> http://www.google. com/custom? q=logic+circuit+ combination+ lock
>
> Secondly, download the datasheet for the L293, easily found using google. You
will notice these chips have a very simple logic table, with something like 3
input signals = enable, input-A, and input-B.
>
> en=0, output=off.
> en=1, A=1, B=0, outputA=1, outputB=0.
> en=1, A=0, B=1, opposite outputs.
>
> Thirdly, build a logic circuit with 3 outputs to go to the 3 inputs of the
L293.
>
> > Hi everyone,
> >
> > My name is Lamis Abdo and i'm new to this group. I'm a senior mechanical
engineer student. In my mechatronics course, i was asked to design for my
first project a DC motor controller connected to a 555 timer and an H-Bridge
L293B so that the motor will turn left and right by the use of switches.
> >
> > My next task is to design and build a circuit made of three PUSH-BUTTON
switches (reset
> > switches) that will form a keypad for password input. Connect this password
to the DC
> > motor controller I made in my first project. The two push-button switches
will be
> > implemented with the following functionalities:  SW1 is used to reset the
circuit, at anytime the DC motor will turn OFF. 
> > one direction.If SW2 THEN SW3 are pressed in sequence after SW1, the DC
motor will turn in 
> > the other direction.If SW3 THEN SW2 are pressed in sequence after SW1, the
DC motor will turn in 
> > turn OFF if it is ON or it will turn ON it it is OFF.
> >  When SW2 AND SW3 are pressed simultaneously at any time, the DC motor
willIn order to design this circuit i need to use logic gates, Flip Flops and
> > integrated circuits (ICs).
> >  
> > I don't know how to start need help if possible!!
> >
>

--- In SeattleRobotics@yahoogroups.com, "David Buckley" <david@...> wrote:
>
> It seems to me, from experience that people who have access to the sort of
robot you are dreaming about, don't have any idea of what to do with it, as if
it is too big a system to comprehend. Liberator I built at Shadow had at one
stage a base with bump sensors, wheel encoders, motor drive circuits and power
management circuitry, a body with an arm and gripper, a head with a vision
system and a brain. Of course since the brain was a Forth computer that
presented a difficulty to most people who could only program spreadsheet macros
or write C code. I won't say program in C since the programs never seemed to
work. What happened to Liberator? Well they took it apart so it couldn't work
and then added bits that didn't work. I get a feeling that buried deep in the
Western psyche is a mistrust of autonomous systems, have you noticed how
difficult it is to get a PC to do anything with being there and clicking on
buttons.
> http://www.davidbuckley.net/DB/Liberator/Liberator.htm
>


Yeah, another fine example of how the robotics hardware is at least a generation
ahead of the software/algorithms for doing AI. However, in the almost decade
since then, maybe there are enough ideas floating aorund re what strategy to
follow. I like a lot of the ideas described in Pfeifer's books.

http://www.amazon.com/How-Body-Shapes-Way-Think\
/dp/0262162393

Namely, developing systems for learning hand-eye coordination [in a robot
possessing the basic mechanisms for doing so], as opposed to what it seems most
AIers do, which is to try and code up algorithms for doing every single tiny
thing. IOW, best to follow an approach which combines aspects of both genetics
and real-world learning from the getgo. Bar-Circle-Cyc-Bar [supposed to be Cyc
in a circle with a bar through it].



>
> Loki is fantastic.
>
> I just happened to have the rubber feet which fitted Simplhex's legs and there
is not much difference with or without the feet except on carpet.
>
> I thought I was the only one who didn't care about the frame rate for servos
being 20.0000000+-00000001 ms. I often dynamically alter the frame rate to
soften the servo action. And in my walkers again I don't care if the frame rate
stretches because the brain is busy reading sensors or displaying variables etc,
the robot just slows down which is exactly what I do.
>


Not just slows down, but without a pulse coming in every 20-msec, the servo
loops don't maintain full torque, so the compliance with regards to external
forces increases significantly.


>
> You can't pump oscillations with slippy feet so you are back to proscribed
motion.
>
> http://www.youtube.com/watch?v=MqP-DhtPh-U
>
> The prototype Hextor demonstrates very well jittering when the feet come down.
The GWS servos are much stiffer than Simplhex's Hitec ones.
>


When I was trying to make my hexapod Nico-6 go fast, I was churning the servos
at about 2X the rate shown in your youtube video [ie, max velocity], and also
made the legs+strides much longer. This caused extreme bashing of the feet
during the footfalls. This is why I am thinking that having a somewhat slippery
"heels" in the feet [plus compliant frame] would help. OTOH, as mentioned, the
"toe ends" would have high friction for stepping off. Bipartate friciton-foot.



>
> Grush isn't radical just realistic. If the sensory/actuation delays in humans
are ~400ms then we have to use some other mechanism to get the 70ms control rate
observed (Grush - 1997 The Architecture of Representation=arch-text.htm <14>) so
it looks as if we know what the >goal values are before we make a move.
>


Or predict what they should be.


>
>Having goal values which you can then do feedback control with is a lot
different from doing IK. Using lookup is also a lot easier and modifying from
experience the lookup values is quite simple. It also doesn't demand a model in
the accepted sense. The model is actually embeded in the lookup values.
>
> David
>


As I see it, lookup is close to how the cerebellum works. It is a huge timing
machine controlling millions of muscle fibers temporally and in parallel, and
the timing is largely learned via practice.

It's a little difficult to imagine the brain would have the power to compute IK
or diff-eqs for the many millions of muscle fibers involved in every single
movement. Too many DOFs.




>
>   ----- Original Message -----
>   From: oric_dan
>   To: SeattleRobotics@yahoogroups.com
>   Sent: Tuesday, November 10, 2009 4:02 AM
>   Subject: [SeattleRobotics] Re: The Wozniak Test
>
>
>
>   --- In SeattleRobotics@yahoogroups.com, "David Buckley" <david@> wrote:
>   >
>   > The Imperial Ladies were Imperial because all the dimensions were based on
inches rather than that communist inspired system where nobody actually
understands (or cares) where to put the decimal point.
>   > Victoria had a Triangle Digital Services 16 bit Forth system and depending
on who you talk to was able to sweep the lawns, make tea and was responsible for
most of the works of Shakespeare. however since I was the only one who ever
programmed the system I am at a loss to explain any such claims.
>   >
>
>   Thanks for the detailed rundown on the Ladies. To me, the general design of
Elizabeth/Robotcop is ideal for both utilitarian work around the house, and also
as a platform for learning sensori-motor behavior, as I mentioned previously. It
has the 3 vital components = vision, manipulators/arms, and mobility. Like the
Scarecrow in WoOz, only needing a really good brain. :)
>
>   http://en.wikipedia.org/wiki/Scarecrow_(Oz)
>
>   And here you built it in 1993/earlier. I have something similar in mind -
only much smaller, but still should be fine for software development.
>
>   I looked around Martin Smith's page, but didn't see much written up on
serious research, publications, etc. Pity. He had a great platform for a
starting basis. Didn't know what to do with it? ???
>
>   BTW, I'm not sure you noticed the (YAL = Yet Another) Loki, that was
discussed a couple of weeks ago. Also, has the 3-vital component parts.
Beautiful implementation, I think. Dave is local to this forum.
>
>   http://www.dshinsel.com/
>
>   >
>   > Just read most of the papers on Rick Grush's page, he uses a lot of words
doesn't he. The sort of model of the brain he describes has seemed to me from
the early 80s onwards to be the only workable model and David Heisermann
described something very similar in his TAB robot books. It allows robots to
dream and be creative. It accommodates the nested feedback loops of Perceptual
Control Theory as well as getting rid of the sums.
>   >
>   > >Rick Grush ....Ie, evolved, predictive motor circuitry in brains
>   > It could be easier if this is massive learned lookup tables and the
evolving is restricted to how to do the lookup.
>   >
>
>   What I really like about Grush's motor emulator theory is the idea that
predictive circuits could have evolved that would be able to greatly improve
motor responsiveness by producing signals internally and used locally, similar
to those that would be expected to be received from the much slower feedback
pathways in the motor circuits.
>
>   Then, if you extend this exact same concept to evolution of higher-order
cognitive pathways, you've really got some powerful predictive circuitry at your
command.
>
>   >
>   > On a foot impact the energy has to go somewhere, hence all the IK sums to
reduce aka 'control' impact. With stiff actuators some of it gets reflected back
into the frame which then interferes with new movements. Simplhex uses HS300
servos near their pullout points and HS300s are not very stiff anyway so the
legs are quite compliant, hence the walk is very smooth even though all 12
servos are run from >a PIC18C84.
>   >
>
>   Thanks for the pointer to Simplhex. It looks like the frame has some good
flexibility there.
>
>   http://davidbuckley.net/DB/Simplhex3/Simplhex3.htm
>
>   If you have access to "How the Body Shapes the Way We Think" by Rolf
Pfeifer, you might take a look at fig. 4.6 on page 133, of Stumpy, also
described here (but without the cool cartoons), as regards how proper
flexibility promotes stability.
>
>   http://www.ifi.uzh.ch/ailab/people/iida/stumpy/
>
>   However, there is another idea that flows out of Pfeifer's books, and also
looking at the movies of Minidog hopping around.
>
>   http://www.ifi.uzh.ch/ailab/people/iida/puppy/
>
>   Whereas Simplhex's feet are rubber all the way around, this means they
cannot "slip" and aid the overall compliance of the frame. However, Iida's
Minidog, and also real dogs' feet do a lot of slipping on hard surfaces. I also
got the impression that much of the jittering in my hexapod frame came from "too
much" friction in the feet, during the bang-down phase.
>
>   So, my brainstorm out of this is the idea of having feet with differing
amounts of friction, front to back. The heels of the feet will be slightly
slippery in order to aid absorption of forces during heel-banging, while the
balls/toes will have high-friction to aid pushing off into the steps. So,
minimize deceleration forces, maximize acceleration forces. Should work ok for
quads/hexapods, probably not as well for bipeds. One day I'll try it. :)
>
>   Speaking of an 18C84 [dinosauric!] servo controller, there is another way to
gain compliance that I've played with, but never actually implemented in a
walker. Ie, if you slowdown the pulse update rate for analog servos to 40-50
msec, the servo feedback loops develop rather wimpish responses. I'm thinking it
would be possible to jigger the servo controller to change the update period in
different parts of the gait. Long [50-msec] when the feet are touching down,
banging and decelerating, but normal [20-msec] when the feet are pushing off and
accelerating. Just another unimplemented idea.
>
>   >
>   This sort of operation was and probably still is an anathema to
EEs/MEs/roboticists since you need a lot more information about the system in
order to do any simulation. Who cares. People still say WOW when Simplhex stands
up because it is so alive looking. Nobody says WOW when Hextor stands up or for
that matter RoboNova, they do say it about Tecfoot-Condor though.
>   >
>   > David
>   >
>
>   "Simulations are always doomed to succeed" - Rod Brooks. Ie, they rarely
take the real physical world adequately into account.
>

----- Original Message -----

From: oric_dan

To: SeattleRobotics@yahoogroups.com

Sent: Tuesday, November 10, 2009 4:02 AM

Subject: [SeattleRobotics] Re: The Wozniak Test

 

--- In SeattleRobotics@yahoogroups.com, "David Buckley" <david@...> wrote:
>
> The Imperial Ladies were Imperial because all the dimensions were based on inches rather than that communist inspired system where nobody actually understands (or cares) where to put the decimal point.
> Victoria had a Triangle Digital Services 16 bit Forth system and depending on who you talk to was able to sweep the lawns, make tea and was responsible for most of the works of Shakespeare. however since I was the only one who ever programmed the system I am at a loss to explain any such claims.
>

Thanks for the detailed rundown on the Ladies. To me, the general design of Elizabeth/Robotcop is ideal for both utilitarian work around the house, and also as a platform for learning sensori-motor behavior, as I mentioned previously. It has the 3 vital components = vision, manipulators/arms, and mobility. Like the Scarecrow in WoOz, only needing a really good brain. :)

http://en.wikipedia.org/wiki/Scarecrow_(Oz)

And here you built it in 1993/earlier. I have something similar in mind - only much smaller, but still should be fine for software development.

I looked around Martin Smith's page, but didn't see much written up on serious research, publications, etc. Pity. He had a great platform for a starting basis. Didn't know what to do with it? ???

BTW, I'm not sure you noticed the (YAL = Yet Another) Loki, that was discussed a couple of weeks ago. Also, has the 3-vital component parts. Beautiful implementation, I think. Dave is local to this forum.

http://www.dshinsel.com/

>
> Just read most of the papers on Rick Grush's page, he uses a lot of words doesn't he. The sort of model of the brain he describes has seemed to me from the early 80s onwards to be the only workable model and David Heisermann described something very similar in his TAB robot books. It allows robots to dream and be creative. It accommodates the nested feedback loops of Perceptual Control Theory as well as getting rid of the sums.
>
> >Rick Grush ....Ie, evolved, predictive motor circuitry in brains
> It could be easier if this is massive learned lookup tables and the evolving is restricted to how to do the lookup.
>

What I really like about Grush's motor emulator theory is the idea that predictive circuits could have evolved that would be able to greatly improve motor responsiveness by producing signals internally and used locally, similar to those that would be expected to be received from the much slower feedback pathways in the motor circuits.

Then, if you extend this exact same concept to evolution of higher-order cognitive pathways, you've really got some powerful predictive circuitry at your command.

>
> On a foot impact the energy has to go somewhere, hence all the IK sums to reduce aka 'control' impact. With stiff actuators some of it gets reflected back into the frame which then interferes with new movements. Simplhex uses HS300 servos near their pullout points and HS300s are not very stiff anyway so the legs are quite compliant, hence the walk is very smooth even though all 12 servos are run from >a PIC18C84.
>

Thanks for the pointer to Simplhex. It looks like the frame has some good flexibility there.

http://davidbuckley.net/DB/Simplhex3/Simplhex3.htm

If you have access to "How the Body Shapes the Way We Think" by Rolf Pfeifer, you might take a look at fig. 4.6 on page 133, of Stumpy, also described here (but without the cool cartoons), as regards how proper flexibility promotes stability.

http://www.ifi.uzh.ch/ailab/people/iida/stumpy/

However, there is another idea that flows out of Pfeifer's books, and also looking at the movies of Minidog hopping around.

http://www.ifi.uzh.ch/ailab/people/iida/puppy/

Whereas Simplhex's feet are rubber all the way around, this means they cannot "slip" and aid the overall compliance of the frame. However, Iida's Minidog, and also real dogs' feet do a lot of slipping on hard surfaces. I also got the impression that much of the jittering in my hexapod frame came from "too much" friction in the feet, during the bang-down phase.

So, my brainstorm out of this is the idea of having feet with differing amounts of friction, front to back. The heels of the feet will be slightly slippery in order to aid absorption of forces during heel-banging, while the balls/toes will have high-friction to aid pushing off into the steps. So, minimize deceleration forces, maximize acceleration forces. Should work ok for quads/hexapods, probably not as well for bipeds. One day I'll try it. :)

Speaking of an 18C84 [dinosauric!] servo controller, there is another way to gain compliance that I've played with, but never actually implemented in a walker. Ie, if you slowdown the pulse update rate for analog servos to 40-50 msec, the servo feedback loops develop rather wimpish responses. I'm thinking it would be possible to jigger the servo controller to change the update period in different parts of the gait. Long [50-msec] when the feet are touching down, banging and decelerating, but normal [20-msec] when the feet are pushing off and accelerating. Just another unimplemented idea.

>
This sort of operation was and probably still is an anathema to EEs/MEs/roboticists since you need a lot more information about the system in order to do any simulation. Who cares. People still say WOW when Simplhex stands up because it is so alive looking. Nobody says WOW when Hextor stands up or for that matter RoboNova, they do say it about Tecfoot-Condor though.
>
> David
>

"Simulations are always doomed to succeed" - Rod Brooks. Ie, they rarely take the real physical world adequately into account.

--- In SeattleRobotics@yahoogroups.com, "David Buckley" <david@...> wrote:
>
> The Imperial Ladies were Imperial because all the dimensions were based on
inches rather than that communist inspired system where nobody actually
understands (or cares) where to put the decimal point.
> Victoria had a Triangle Digital Services 16 bit Forth system and depending on
who you talk to was able to sweep the lawns, make tea and was responsible for
most of the works of Shakespeare. however since I was the only one who ever
programmed the system I am at a loss to explain any such claims.
>


Thanks for the detailed rundown on the Ladies. To me, the general design of
Elizabeth/Robotcop is ideal for both utilitarian work around the house, and also
as a platform for learning sensori-motor behavior, as I mentioned previously. It
has the 3 vital components = vision, manipulators/arms, and mobility. Like the
Scarecrow in WoOz, only needing a really good brain. :)

http://en.wikipedia.org/wiki/Scarecrow_(Oz)

And here you built it in 1993/earlier. I have something similar in mind - only
much smaller, but still should be fine for software development.

I looked around Martin Smith's page, but didn't see much written up on serious
research, publications, etc. Pity. He had a great platform for a starting basis.
Didn't know what to do with it? ???

BTW, I'm not sure you noticed the (YAL = Yet Another) Loki, that was discussed a
couple of weeks ago. Also, has the 3-vital component parts. Beautiful
implementation, I think. Dave is local to this forum.

http://www.dshinsel.com/



>
> Just read most of the papers on Rick Grush's page, he uses a lot of words
doesn't he. The sort of model of the brain he describes has seemed to me from
the early 80s onwards to be the only workable model and David Heisermann
described something very similar in his TAB robot books. It allows robots to
dream and be creative. It accommodates the nested feedback loops of Perceptual
Control Theory as well as getting rid of the sums.
>
> >Rick Grush ....Ie, evolved, predictive motor circuitry in brains
> It could be easier if this is massive learned lookup tables and the evolving
is restricted to how to do the lookup.
>


What I really like about Grush's motor emulator theory is the idea that
predictive circuits could have evolved that would be able to greatly improve
motor responsiveness by producing signals internally and used locally, similar
to those that would be expected to be received from the much slower feedback
pathways in the motor circuits.

Then, if you extend this exact same concept to evolution of higher-order
cognitive pathways, you've really got some powerful predictive circuitry at your
command.



>
> On a foot impact the energy has to go somewhere, hence all the IK sums to
reduce aka 'control' impact. With stiff actuators some of it gets reflected back
into the frame which then interferes with new movements. Simplhex uses HS300
servos near their pullout points and HS300s are not very stiff anyway so the
legs are quite compliant, hence the walk is very smooth even though all 12
servos are run from >a PIC18C84.
>


Thanks for the pointer to Simplhex. It looks like the frame has some good
flexibility there.

http://davidbuckley.net/DB/Simplhex3/Simplhex3.htm

If you have access to "How the Body Shapes the Way We Think" by Rolf Pfeifer,
you might take a look at fig. 4.6 on page 133, of Stumpy, also described here
(but without the cool cartoons), as regards how proper flexibility promotes
stability.

http://www.ifi.uzh.ch/ailab/people/iida/stumpy/

However, there is another idea that flows out of Pfeifer's books, and also
looking at the movies of Minidog hopping around.

http://www.ifi.uzh.ch/ailab/people/iida/puppy/

Whereas Simplhex's feet are rubber all the way around, this means they cannot
"slip" and aid the overall compliance of the frame. However, Iida's Minidog, and
also real dogs' feet do a lot of slipping on hard surfaces. I also got the
impression that much of the jittering in my hexapod frame came from "too much"
friction in the feet, during the bang-down phase.

So, my brainstorm out of this is the idea of having feet with differing amounts
of friction, front to back. The heels of the feet will be slightly slippery in
order to aid absorption of forces during heel-banging, while the balls/toes will
have high-friction to aid pushing off into the steps. So, minimize deceleration
forces, maximize acceleration forces. Should work ok for quads/hexapods,
probably not as well for bipeds. One day I'll try it. :)

Speaking of an 18C84 [dinosauric!] servo controller, there is another way to
gain compliance that I've played with, but never actually implemented in a
walker. Ie, if you slowdown the pulse update rate for analog servos to 40-50
msec, the servo feedback loops develop rather wimpish responses. I'm thinking it
would be possible to jigger the servo controller to change the update period in
different parts of the gait. Long [50-msec] when the feet are touching down,
banging and decelerating, but normal [20-msec] when the feet are pushing off and
accelerating. Just another unimplemented idea.




>
This sort of operation was and probably still is an anathema to
EEs/MEs/roboticists since you need a lot more information about the system in
order to do any simulation. Who cares. People still say WOW when Simplhex stands
up because it is so alive looking. Nobody says WOW when Hextor stands up or for
that matter RoboNova, they do say it about Tecfoot-Condor though.
>
> David
>


"Simulations are always doomed to succeed" - Rod Brooks. Ie, they rarely take
the real physical world adequately into account.

----- Original Message -----

From: oric_dan

To: SeattleRobotics@yahoogroups.com

Sent: Monday, November 09, 2009 5:46 PM

Subject: [SeattleRobotics] Re: The Wozniak Test

 

--- In SeattleRobotics@yahoogroups.com, "David Buckley" <david@...> wrote:
>
> Hi
> Bimbo Town, bit of a mystery.
...........
> Just looked at your link to BimboTown, more pictures of me again, Rebecca in the 'smalltalk' photo was quite stunning.
>

Following link calls Bimbotown "the world's only robotic nightclub". Sounds pretty decriptive. Has some good pictures of the robotic drummer.

http://www.extremearts.co.uk/

The more I look at your site, the more amazed I am! I notice robot designs you built back in 1993 that I am just beginning to try to emulate today [on a much smaller scale however, LOL]. They look like great platforms to build robotic-AI upon. Were/are they ROV or autonomous? Has anyone done extensive research with them? Martin Smith?

http://davidbuckley.net/DB/ImperialLadies.htm

>
> The flexibility and soft approach to being right, necessary to perform usefully in a human (animal) society will be needed in robots. They will look generally predictable (as sane humans are) although we won't be able to predict on a fine scale. Condor my best walking robot has just undergone a dual hip replacement, it was showing signs of wear. Now it performs better and it gave me an oportunity to get the program to dynamically adjust the side to side rock. However now sometimes Condor appears to stop and ponder which way to go and at other times appears nervous as if it isn't quite sure. These are just artifacts of the interplay of program and the mechanical resonance and spatio temporal changes in the perceived >environment.
>

Yes, this is similar to what Rolf Pfeifer talks about in his books as "morphological computation", and Rbt Full calls mechanical "preflexes". When I was testing one of hexapod walkers at different speeds, I noticed the faster I tried to make it go, the more it became jerky and unstable. From reading Pfeifer and Full, I think the frame was far too rigid, and eventually plan to build better flexibility in future walkers, so the frame can self-adjust to hard foot-impacts.

>
> Once we abandon all the inverse kinematics and pretending humanoid robots are just human looking machine tools which WILL/MUST work as in the screen simulation then stuff like being ablr to do the Woz test will naturally follow. Something I realised the other day is that on the occasions when Asimo has fallen down there is no recovery procedure for it to follow, once it gets out of the enveloppe, it locks into the last command position and CRASH.
>
> David
>

This is an interesting thought - abandoning IK. Opposite stance to the totally computational approach of the past 50-years. Of course, this is what Pfeifer and Full are also saying. After all, brains don't compute diff-eqs, they largely reproduce learned patterns of muscle movements, and use sensors and feedback for real-time adjustments.

OTOH, the motor emulation stuff of Rick Grush is very interesting. Ie, evolved, predictive motor circuitry in brains.

http://mind.ucsd.edu/

It's Monday, It's Fall, It's Robot Building Season!

Come join us on our Weekly Monday Night Chat and see what all the fuss is about.


I hear the Freenode has had issues with Mibbit and would rather us use their
webchat gateway for those that don't want to install their own IRC software.

So to use webchat use the link

http://tinyurl.com/SRS-Chat

Which points too:

http://webchat.freenode.net/?channels=SeattleRobotics

And of course, all the standalone IRC clients work, and you should be able to
get them working with the answers below or on the Seattle Robotics website. 
seattlerobotics.org under Contact us.



Richard
/* ----------------------------------------- */

The Seattle Robotics Society hosts a "Monday Night Chat" each week.

Starting at 7pm Seattle Time each Monday, the SRS holds an
informal chat session. This is a great opportunity to come ask live
questions of the SRS members, seek help for technical problems, or
just chat about stuff.

Directions:

For you experts, the chat is held on irc.freenode.net in the
#seattlerobotics group.


New web chat interface!
No Software to install.

http://tinyurl.com/SRS-Chat

Tiny URL points to:

http://webchat.freenode.net/?channels=SeattleRobotics


If you register with mibbit, it also allows you to post files to share
and log chat sessions. But there is no need to do that to participate.

Chatzilla is still the most recommended interface to Monday Night
Chat. And once installed (Along with the Firefox web browser), the
chat can be accessed from this link.

irc://irc.freenode.net/#SeattleRobotics


Directions for mIRC which may be applicable to other IRC chat clients
can be found at the SRS Homepage at
http://www.seattlerobotics.org
in the contact us link at:
http://seattlerobotics.org/contact.php



For Mac Users:
http://colloquy.info/
(Umm I don't actually have experience setting this up, but you should
be able to figure it out from the directions on the Contact page of the Seattle
Robotics website.

http://www.seattlerobotics.org



Message Ends

--- In SeattleRobotics@yahoogroups.com, Lamis Abdo <lamis_abdo@...> wrote:
>


Hello Lamis. This is a simple problem for someone in an EE program, and who has
taken a basic course in logic. Sounds like you are neither. I am surprised that
25 other people on this forum have not responded. Probably no one wants to
simply "give you the answer". After all, it's a design course. You're in school.

First, follow up on simple combination locks using google.

http://www.discovercircuits.com/E/elec-lock.htm

http://www.google.com/custom?q=logic+circuit+combination+lock

Secondly, download the datasheet for the L293, easily found using google. You
will notice these chips have a very simple logic table, with something like 3
input signals = enable, input-A, and input-B.

en=0, output=off.
en=1, A=1, B=0, outputA=1, outputB=0.
en=1, A=0, B=1, opposite outputs.

Thirdly, build a logic circuit with 3 outputs to go to the 3 inputs of the L293.



> Hi everyone,
>
> My name is Lamis Abdo and i'm new to this group. I'm a senior mechanical
engineer student. In my mechatronics course, i was asked to design for my
first project a DC motor controller connected to a 555 timer and an H-Bridge
L293B so that the motor will turn left and right by the use of switches.
>
> My next task is to design and build a circuit made of three PUSH-BUTTON
switches (reset
> switches) that will form a keypad for password input. Connect this password to
the DC
> motor controller I made in my first project. The two push-button switches will
be
> implemented with the following functionalities: SW1 is used to reset the
circuit, at anytime the DC motor will turn OFF. 
> one direction.If SW2 THEN SW3 are pressed in sequence after SW1, the DC motor
will turn in 
> the other direction.If SW3 THEN SW2 are pressed in sequence after SW1, the DC
motor will turn in 
> turn OFF if it is ON or it will turn ON it it is OFF.
>  When SW2 AND SW3 are pressed simultaneously at any time, the DC motor willIn
order to design this circuit i need to use logic gates, Flip Flops and
> integrated circuits (ICs).
>  
> I don't know how to start need help if possible!!
>

--- In SeattleRobotics@yahoogroups.com, "David Buckley" <david@...> wrote:
>
> Hi
> Bimbo Town, bit of a mystery.
...........
> Just looked at your link to BimboTown, more pictures of me again, Rebecca in
the 'smalltalk' photo was quite stunning.
>


Following link calls Bimbotown "the world's only robotic nightclub". Sounds
pretty decriptive. Has some good pictures of the robotic drummer.

http://www.extremearts.co.uk/

The more I look at your site, the more amazed I am! I notice robot designs you
built back in 1993 that I am just beginning to try to emulate today [on a much
smaller scale however, LOL]. They look like great platforms to build robotic-AI
upon. Were/are they ROV or autonomous? Has anyone done extensive research with
them? Martin Smith?

http://davidbuckley.net/DB/ImperialLadies.htm



>
> The flexibility and soft approach to being right, necessary to perform
usefully in a human (animal) society will be needed in robots. They will look
generally predictable (as sane humans are) although we won't be able to predict
on a fine scale. Condor my best walking robot has just undergone a dual hip
replacement, it was showing signs of wear. Now it performs better and it gave me
an oportunity to get the program to dynamically adjust the side to side rock.
However now sometimes Condor appears to stop and ponder which way to go and at
other times appears nervous as if it isn't quite sure. These are just artifacts
of the interplay of program and the mechanical resonance and spatio temporal
changes in the perceived >environment.
>


Yes, this is similar to what Rolf Pfeifer talks about in his books as
"morphological computation", and Rbt Full calls mechanical "preflexes". When I
was testing one of hexapod walkers at different speeds, I noticed the faster I
tried to make it go, the more it became jerky and unstable. From reading Pfeifer
and Full, I think the frame was far too rigid, and eventually plan to build
better flexibility in future walkers, so the frame can self-adjust to hard
foot-impacts.


>
> Once we abandon all the inverse kinematics and pretending humanoid robots are
just human looking machine tools which WILL/MUST work as in the screen
simulation then stuff like being ablr to do the Woz test will naturally follow.
Something I realised the other day is that on the occasions when Asimo has
fallen down there is no recovery procedure for it to follow, once it gets out of
the enveloppe, it locks into the last command position and CRASH.
>
> David
>


This is an interesting thought - abandoning IK. Opposite stance to the totally
computational approach of the past 50-years. Of course, this is what Pfeifer and
Full are also saying. After all, brains don't compute diff-eqs, they largely
reproduce learned patterns of muscle movements, and use sensors and feedback for
real-time adjustments.

OTOH, the motor emulation stuff of Rick Grush is very interesting. Ie, evolved,
predictive motor circuitry in brains.

http://mind.ucsd.edu/

Jon

> I've never tried to do a shutdown while its sending/receiving data
> though. Might be a driver bug in that case - hard to say...

It's the sort of situation that can easily occur if you have a remote "data
collection" gizmo which transmits data continuously. After all, why
shouldn't the gizmo just send continuously - why would that ever harm
anyone?

We sell the equipment to rather unsophisticated users and closing down
windows without first stopping the gizmo will seem very reasonable to them -
as it does to me.

Of course, the "gizmo" might well be a robot sending back telemetry data.

It you have the courage, try shutting down windows while its receiving data.
If you don't then, one day, one of your customers will and they'll blame you
if somethings bad happens.

However, it was all a few years ago and AFAIK, disk-trashing no longer
occrus with more modern converters and OS releases.

===

Alex

> Following is the description from the Garmin GPS18x technical spec. ...

That is dreadful. What on earth are microsoft playing at to let that sort of
thing happen?

If it really is just a problem with the BallPoint mouse driver then let's
all just delete our drivers. After all, how many of us have BallPoint mice?

However, if it can happen with any microsoft mouse driver, it means that I
have to ensure that certain magic byte sequences can never occur in my data.

Does anyone know what the "magic byte sequences" are?

===

Dave

> We've had lots of problems with drivers crashing, usually resulting in
> a blue screen.

But no data loss right? In our original investigations, we would sometimes
get the blue screen without trashing the drive and sometimes with a
trashing. I can't remember the ratio but trashing was fairly common.

> My all time favorite USB-serial converter is this one:
> http://sewelldirect.com/usbtoserial.asp
> I can't recall ever seeing a blue screen with this particular adapter.

Thanks

Clearly, other people have investigated the problems with converters:
http://www.clearone.com/docs/tech_notes/801-155-000-22-Rev2.0_XAPGWARE122.pdf
http://www.nadler.com/sn10/SN10_USB_Serial_Notes.html

If you google "USB to Serial adapter blue screen of death" you get an awful
lot of hits.

Peter