Alt-BEAM Archive

Message #13746



To: "'beam@sgiblab.sgi.com'" beam@sgiblab.sgi.com
From: Wilf Rigter wilf.rigter@powertech.bc.ca
Date: Thu, 20 Apr 2000 10:42:33 -0700
Subject: RE: Servo Controler


Yup, a 74HC04 works like a HC240 but doesn't have tristate or (much) motor
drive capability. Use it for oscillators, bicores, etc.
Of course don't use 74LS/ALS/F/S04 etc which all suck too much power and are
not compatible with large input resistors..

wilf


> -----Original Message-----
> From: Richard Piotter [SMTP:richfile@rconnect.com]
> Sent: Thursday, April 20, 2000 10:10 AM
> To: beam@sgiblab.sgi.com
> Subject: Re: Servo Controler
>
> Just one question? You can use the 7404 like that? Didn't realize that!
> I'll have to grab a couple & expiriment.
>
> Wilf Rigter wrote:
> >
> > Try this for less parts
> >
> > <>
> >
> > The binary inputs IN1 and IN2 control the PWM as follows.
> >
> > 0 0 = CW
> > 1 0 = CENTER
> > 0 1 = CCW
> > 1 1 = HOLD
> >
> > The HOLD function forces the PWM output low and the servo will remain in
> > it's present position for a short while.
> > Raising the ENABLE line high forces the PWM output high and is probably
> not
> > very useful.
> >
> > wilf
> >
> > > -----Original Message-----
> > > From: Richard Piotter [SMTP:richfile@rconnect.com]
> > > Sent: Wednesday, April 19, 2000 9:20 PM
> > > To: Twin Cities Robotics Group; BEAM
> > > Subject: Servo Controler
> > >
> > > Does this circuit look decent?
> > >
> > > 1x 74HC14 (6 inverter gates)
> > > 1x 74xx00 (3 NAND gates)
> > > 1x 74xx08 (2 AND gates)
> > > 3x Silicon Switching Diodes
> > > 3x Multiturn Potentiometer
> > > 2x Small Value Resistors
> > > 2x Capacitors
> > >
> > > ___
> > > ,----|>o--| \
> > > | | |o--|<--o--/\/\/---.
> > > | o--|>o--|___/ | ^ |
> > > | | |____| |
> > > | | ___ |
> > > o----|>o--| \ |
> > > | | | |o--|<--o--/\/\/---o
> > > | o-------|___/ | ^ |
> > > In | | |____| |
> > > A | | ___ |
> > > O--o---------| \ |
> > > | | | |o--|<--o--/\/\/---o
> > > O----o--|>o--|___/ | ^ |
> > > In | | |____| |
> > > B | | ___ |
> > > o---------| \ |
> > > | | |--. |
> > > '-------|___/ | ,--/\/\/--o--/\/\/--.
> > > | | |
> > > | o----|>o-----||-----o
> > > ___ | | |
> > > / |--' '-----||--o--o<|----'
> > > O------------| | |
> > > Servo \___|------------------'
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > --
> > >
> > >
> > > Richard Piotter The Richfiles Robotics & TI web page:
> > > richfile@rconnect.com http://richfiles.calc.org
> > >
> > > -- Make Money by Simply Surfing the Net or responding to E-Mail!!!
> > > -- Click below!!!
> > >
> > > http://www.alladvantage.com/go.asp?refid=ATL147
> > > http://www.spedia.net/cgi-bin/dir/tz.cgi?run=show_svc&fl=8&vid=329630
> >
> >
> ------------------------------------------------------------------------
> > Name: SERVOLOGIC.gif
> > SERVOLOGIC.gif Type: GIF Image (image/gif)
> > Encoding: base64
>
> --
>
>
> Richard Piotter The Richfiles Robotics & TI web page:
> richfile@rconnect.com http://richfiles.calc.org
>
> -- Make Money by Simply Surfing the Net or responding to E-Mail!!!
> -- Click below!!!
>
> http://www.alladvantage.com/go.asp?refid=ATL147
> http://www.spedia.net/cgi-bin/dir/tz.cgi?run=show_svc&fl=8&vid=329630



13747 Thu, 20 Apr 2000 13:47:44 EDT Re: Solarizing beam@sgiblab.sgi.com JVernonM@aol.com In a message dated 4/20/00 1:12:17 PM Eastern Daylight Time,
Wilf.Rigter@powertech.bc.ca writes:

> This is the venerable D1 circuit but the diode has been replaced with a
> 2N3904 transistor.
Thanks Wilf. I'll play with the circuit and see what it will do. This
avoidance behavior has me very interested. I would think other interactive
applications of the circuit would work as well. You're one in a million swami.

See ya,
Jim
http://www.geocities.com/SoHo/Exhibit/8281/beamart.html
ICQ# 55657870



13748 Thu, 20 Apr 2000 11:03:17 -0700 My Poor Walker (Its kicking its legs around like a wild....) beam@sgiblab.sgi.com Bernard Nazari Hi All,
Well, I'm still working on my walker and I've gotten the circuit down
flat. The PCBs are perfect, the servos are crankin...there are two small
problems....The legs aren't turning at the same rate, but that can be
fixed with a couple of pots. The problem I can't solve is this: Lets say
that I turn the bot off when the front leg has just finished turning CCW;
but when I turn it back on, the first move is to turn the front leg CCW.
That leads to one screwy looking walker. :-) Do you just rotate the legs to
an "initial" state right before power up or is there some way to center
out the servos using the original circuitry and controller. I've heard talk
about using the pot that's inside the servo to help it focused. (Roughly
what's the value of that thing...mine are reduced down to shafts that
rotate. Ahh, the power of a pliers!) But on top of that, is there some way
to use the servo in the original retail state? I saw Wilf's circuit in the
"Servo controller" thread, but I'm having a wee bit of trouble implementing
that into my walker. (I'm using a 4Nv microcore right now, I'm going to
take that up to 6Nv for the next walker.) Anyway, I'm off to buy some more
components!
-Bernie
----------------------------------------------------------------------------
--------------------
DISCLAIMER: JPL now requires notice in all electronic communication
that all personal and professional opinions presented herein are my
own and do not, in any way, represent the opinion or policy of JPL.



13749 Thu, 20 Apr 2000 10:58:49 -0700 Re: 74xxx14 vs. 74xxx240 beam@sgiblab.sgi.com Bruce Robinson Xaphiosis wrote:
>
> ... what is the difference between the 74xxx14
> (hex inverter) and 74xxx240 (octal driver)?

1) Six inverters vs. eight :)
2) The '240 is a driver, so can handle roughly twice the current.
3) Most important, the '14 is a Schmitt inverter, meaning the
input voltage at which it switches to a high output is
guaranteed to be higher than the input voltage at which it
switches to a lower voltage (Hysteresis to be precise :)

On a slow-rising input (such as in a microcore), the Schmitt inverter
ensures a very clean on/off transistion. A regular inverter, when it
gets near it's transition point, might switch on and off several times
if there is any noise in the circuit (say from motors or other devices).
A Schmitt device won't, because once it's on, the input voltage has to
drop quite a bit before it can switch off.

Bruce



13750 Thu, 20 Apr 2000 13:25:03 -0700 RE: My Poor Walker (Its kicking its legs around like a wild....) "'beam@sgiblab.sgi.com'" Wilf Rigter Hi Bernie,

If you already have a microcore then a "retail state servo" PWM controller
can be added like this. This design is not yet tested but barring some
component value changes, it should work. You'll also need some sort of PNC
for the microcore. Note the diode logic required for CW, CCW, and hold.
This circuit can be simplified and I am curious to see how turning and
reversing will evolve from this idea.

regards

wilf



> -----Original Message-----
> From: Bernard Nazari [SMTP:Bernard.Nazari@jpl.nasa.gov]
> Sent: Thursday, April 20, 2000 11:03 AM
> To: beam@sgiblab.sgi.com
> Subject: My Poor Walker (Its kicking its legs around like a wild....)
>
> Hi All,
> Well, I'm still working on my walker and I've gotten the circuit
> down
> flat. The PCBs are perfect, the servos are crankin...there are two small
> problems....The legs aren't turning at the same rate, but that can be
> fixed with a couple of pots. The problem I can't solve is this: Lets say
> that I turn the bot off when the front leg has just finished turning CCW;
> but when I turn it back on, the first move is to turn the front leg CCW.
> That leads to one screwy looking walker. :-) Do you just rotate the legs
> to
> an "initial" state right before power up or is there some way to center
> out the servos using the original circuitry and controller. I've heard
> talk
> about using the pot that's inside the servo to help it focused. (Roughly
> what's the value of that thing...mine are reduced down to shafts that
> rotate. Ahh, the power of a pliers!) But on top of that, is there some way
>
> to use the servo in the original retail state? I saw Wilf's circuit in the
>
> "Servo controller" thread, but I'm having a wee bit of trouble
> implementing
> that into my walker. (I'm using a 4Nv microcore right now, I'm going to
> take that up to 6Nv for the next walker.) Anyway, I'm off to buy some more
>
> components!
> -Bernie
> --------------------------------------------------------------------------
> --
> --------------------
> DISCLAIMER: JPL now requires notice in all electronic communication
> that all personal and professional opinions presented herein are my
> own and do not, in any way, represent the opinion or policy of JPL.



13751 Thu, 20 Apr 2000 16:34:50 EDT One more bot beam@sgiblab.sgi.com JVernonM@aol.com Hey all,
I just posted another finished bot. Look under Carbots/probebot1 on my site.

See ya,
Jim
http://www.geocities.com/SoHo/Exhibit/8281/beamart.html
ICQ# 55657870



13752 Thu, 20 Apr 2000 16:01:09 -0500 Re: Servo Controler beam@sgiblab.sgi.com Richard Piotter So it has to be HC/HCT? NUTS!!!

Will the 74HC14 work in place of the 74HC04? The school doesn't have the
HC version in the parts shelves.



Wilf Rigter wrote:
>
> Yup, a 74HC04 works like a HC240 but doesn't have tristate or (much) motor
> drive capability. Use it for oscillators, bicores, etc.
> Of course don't use 74LS/ALS/F/S04 etc which all suck too much power and are
> not compatible with large input resistors..
>
> wilf
>
> > -----Original Message-----
> > From: Richard Piotter [SMTP:richfile@rconnect.com]
> > Sent: Thursday, April 20, 2000 10:10 AM
> > To: beam@sgiblab.sgi.com
> > Subject: Re: Servo Controler
> >
> > Just one question? You can use the 7404 like that? Didn't realize that!
> > I'll have to grab a couple & expiriment.
> >
> > Wilf Rigter wrote:
> > >
> > > Try this for less parts
> > >
> > > <>
> > >
> > > The binary inputs IN1 and IN2 control the PWM as follows.
> > >
> > > 0 0 = CW
> > > 1 0 = CENTER
> > > 0 1 = CCW
> > > 1 1 = HOLD
> > >
> > > The HOLD function forces the PWM output low and the servo will remain in
> > > it's present position for a short while.
> > > Raising the ENABLE line high forces the PWM output high and is probably
> > not
> > > very useful.
> > >
> > > wilf
> > >
> > > > -----Original Message-----
> > > > From: Richard Piotter [SMTP:richfile@rconnect.com]
> > > > Sent: Wednesday, April 19, 2000 9:20 PM
> > > > To: Twin Cities Robotics Group; BEAM
> > > > Subject: Servo Controler
> > > >
> > > > Does this circuit look decent?
> > > >
> > > > 1x 74HC14 (6 inverter gates)
> > > > 1x 74xx00 (3 NAND gates)
> > > > 1x 74xx08 (2 AND gates)
> > > > 3x Silicon Switching Diodes
> > > > 3x Multiturn Potentiometer
> > > > 2x Small Value Resistors
> > > > 2x Capacitors
> > > >
> > > > ___
> > > > ,----|>o--| \
> > > > | | |o--|<--o--/\/\/---.
> > > > | o--|>o--|___/ | ^ |
> > > > | | |____| |
> > > > | | ___ |
> > > > o----|>o--| \ |
> > > > | | | |o--|<--o--/\/\/---o
> > > > | o-------|___/ | ^ |
> > > > In | | |____| |
> > > > A | | ___ |
> > > > O--o---------| \ |
> > > > | | | |o--|<--o--/\/\/---o
> > > > O----o--|>o--|___/ | ^ |
> > > > In | | |____| |
> > > > B | | ___ |
> > > > o---------| \ |
> > > > | | |--. |
> > > > '-------|___/ | ,--/\/\/--o--/\/\/--.
> > > > | | |
> > > > | o----|>o-----||-----o
> > > > ___ | | |
> > > > / |--' '-----||--o--o<|----'
> > > > O------------| | |
> > > > Servo \___|------------------'
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > --
> > > >
> > > >
> > > > Richard Piotter The Richfiles Robotics & TI web page:
> > > > richfile@rconnect.com http://richfiles.calc.org
> > > >
> > > > -- Make Money by Simply Surfing the Net or responding to E-Mail!!!
> > > > -- Click below!!!
> > > >
> > > > http://www.alladvantage.com/go.asp?refid=ATL147
> > > > http://www.spedia.net/cgi-bin/dir/tz.cgi?run=show_svc&fl=8&vid=329630
> > >
> > >
> > ------------------------------------------------------------------------
> > > Name: SERVOLOGIC.gif
> > > SERVOLOGIC.gif Type: GIF Image (image/gif)
> > > Encoding: base64
> >
> > --
> >
> >
> > Richard Piotter The Richfiles Robotics & TI web page:
> > richfile@rconnect.com http://richfiles.calc.org
> >
> > -- Make Money by Simply Surfing the Net or responding to E-Mail!!!
> > -- Click below!!!
> >
> > http://www.alladvantage.com/go.asp?refid=ATL147
> > http://www.spedia.net/cgi-bin/dir/tz.cgi?run=show_svc&fl=8&vid=329630

--


Richard Piotter The Richfiles Robotics & TI web page:
richfile@rconnect.com http://richfiles.calc.org

-- Make Money by Simply Surfing the Net or responding to E-Mail!!!
-- Click below!!!

http://www.alladvantage.com/go.asp?refid=ATL147
http://www.spedia.net/cgi-bin/dir/tz.cgi?run=show_svc&fl=8&vid=329630



13753 Thu, 20 Apr 2000 14:18:06 -0700 RE: My Poor Walker (Its kicking its legs around like a wild....) "'beam@sgiblab.sgi.com'" Wilf Rigter
oops!

here it is:

<>

> -----Original Message-----
> From: Wilf Rigter [SMTP:Wilf.Rigter@powertech.bc.ca]
> Sent: Thursday, April 20, 2000 1:25 PM
> To: 'beam@sgiblab.sgi.com'
> Subject: RE: My Poor Walker (Its kicking its legs around like a
> wild....)
>
> Hi Bernie,
>
> If you already have a microcore then a "retail state servo" PWM controller
> can be added like this. This design is not yet tested but barring some
> component value changes, it should work. You'll also need some sort of PNC
> for the microcore. Note the diode logic required for CW, CCW, and hold.
> This circuit can be simplified and I am curious to see how turning and
> reversing will evolve from this idea.
>
> regards
>
> wilf
>
>
>
> > -----Original Message-----
> > From: Bernard Nazari [SMTP:Bernard.Nazari@jpl.nasa.gov]
> > Sent: Thursday, April 20, 2000 11:03 AM
> > To: beam@sgiblab.sgi.com
> > Subject: My Poor Walker (Its kicking its legs around like a wild....)
> >
> > Hi All,
> > Well, I'm still working on my walker and I've gotten the circuit
> > down
> > flat. The PCBs are perfect, the servos are crankin...there are two small
>
> > problems....The legs aren't turning at the same rate, but that can be
> > fixed with a couple of pots. The problem I can't solve is this: Lets say
>
> > that I turn the bot off when the front leg has just finished turning
> CCW;
> > but when I turn it back on, the first move is to turn the front leg CCW.
>
> > That leads to one screwy looking walker. :-) Do you just rotate the legs
> > to
> > an "initial" state right before power up or is there some way to center
>
> > out the servos using the original circuitry and controller. I've heard
> > talk
> > about using the pot that's inside the servo to help it focused. (Roughly
>
> > what's the value of that thing...mine are reduced down to shafts that
> > rotate. Ahh, the power of a pliers!) But on top of that, is there some
> way
> >
> > to use the servo in the original retail state? I saw Wilf's circuit in
> the
> >
> > "Servo controller" thread, but I'm having a wee bit of trouble
> > implementing
> > that into my walker. (I'm using a 4Nv microcore right now, I'm going to
> > take that up to 6Nv for the next walker.) Anyway, I'm off to buy some
> more
> >
> > components!
> > -Bernie
> >
> --------------------------------------------------------------------------
> > --
> > --------------------
> > DISCLAIMER: JPL now requires notice in all electronic communication
> > that all personal and professional opinions presented herein are my
> > own and do not, in any way, represent the opinion or policy of JPL.


13754 Thu, 20 Apr 2000 15:17:38 -0600 Re: One more bot beam@sgiblab.sgi.com "John A. deVries II" At 02:34 PM 4/20/00 , Jim wrote:
>Hey all,
>I just posted another finished bot. Look under Carbots/probebot1 on my site.
>http://www.geocities.com/SoHo/Exhibit/8281/beamart.html


Darn! (don't want to use what might be construed as a nasty word)

That is one handsome piece of BEAM!!


Zoz

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