to servo or not to servo!
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Posts: 46,084
Okay guys, here is goes.
I want to make a dish positioning system for a friend of mine. Now I
know that I could use modified servo motors. But I am afraid that
the servos would be to large and expensive. My other thought was to
use old windshield wiper motors which would be much less expensive
than the servos, but I don't know if I can get too accurate with this
type of set up. What do you guys think? Any suggestions would be
appreciated.
Thanks in advance!!
Frank G.
I want to make a dish positioning system for a friend of mine. Now I
know that I could use modified servo motors. But I am afraid that
the servos would be to large and expensive. My other thought was to
use old windshield wiper motors which would be much less expensive
than the servos, but I don't know if I can get too accurate with this
type of set up. What do you guys think? Any suggestions would be
appreciated.
Thanks in advance!!
Frank G.
Comments
position of the dish. If I remember right, the old C-band dishes used a
screw-jack to move the dish and a linear-actuated potentiometer to measure
the position.
Keep in mind if you use regular gears you need quite a bit of reduction to
keep the dish from turning the motor in a high wind. A worm gear works well
for this as it will hold is position.
How big a dish are we talking?
Original Message
> I want to make a dish positioning system for a friend of mine. Now I
> know that I could use modified servo motors. But I am afraid that
> the servos would be to large and expensive. My other thought was to
> use old windshield wiper motors which would be much less expensive
> than the servos, but I don't know if I can get too accurate with this
> type of set up. What do you guys think? Any suggestions would be
> appreciated.
antenna can be very substantial. Whatever you end up with it will be
beefy. Also, this positioning requires the dish be positioned on 2
axis, azimuth and elevation.
I would not attempt this myself, to many technical and mechanical
obstacles. Simply holding the dish in place will require a brake of
some kind. Relying on gearing to hold the dish in place is not a good
idea, besides, it probably wont work. (Take this from a ham who has
been pointing antennas for more than a few years.
Whatever you end up with will be more expensive, and possibly less
reliable, than an off-the-shelf az-el positioner.
Regards
Rich
--- In basicstamps@y..., fwankg@y... wrote:
> Okay guys, here is goes.
>
> I want to make a dish positioning system for a friend of mine. Now
I
> know that I could use modified servo motors. But I am afraid that
> the servos would be to large and expensive. My other thought was
to
> use old windshield wiper motors which would be much less expensive
> than the servos, but I don't know if I can get too accurate with
this
> type of set up. What do you guys think? Any suggestions would be
> appreciated.
>
> Thanks in advance!!
>
> Frank G.
the old 'C' band satellite be an option? I would think these would be
pretty cheap, readily available at a Ham Fest and easy to interface to
the stamp. Just a thought!!
Leroy
iceninevt@y... wrote:
>
> You did not mention the size of the dish. The wind load on a dish
> antenna can be very substantial. Whatever you end up with it will be
> beefy. Also, this positioning requires the dish be positioned on 2
> axis, azimuth and elevation.
>
> I would not attempt this myself, to many technical and mechanical
> obstacles. Simply holding the dish in place will require a brake of
> some kind. Relying on gearing to hold the dish in place is not a good
> idea, besides, it probably wont work. (Take this from a ham who has
> been pointing antennas for more than a few years.
>
> Whatever you end up with will be more expensive, and possibly less
> reliable, than an off-the-shelf az-el positioner.
>
> Regards
>
> Rich
>
> --- In basicstamps@y..., fwankg@y... wrote:
> > Okay guys, here is goes.
> >
> > I want to make a dish positioning system for a friend of mine. Now
> I
> > know that I could use modified servo motors. But I am afraid that
> > the servos would be to large and expensive. My other thought was
> to
> > use old windshield wiper motors which would be much less expensive
> > than the servos, but I don't know if I can get too accurate with
> this
> > type of set up. What do you guys think? Any suggestions would be
> > appreciated.
> >
> > Thanks in advance!!
> >
> > Frank G.
>
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--
*******************************************************
* Leroy Hall *
* 317 Cherokee Drive *
* Loveland, Ohio - USA 45140-2404 *
*******************************************************
* Phone: (513) 697-7539 *
* Cell : (513) 300-8632 *
* Email: leroy@f... *
* Home page URL: http://home.fuse.net/leroy/ *
* Resume URL: http://home.fuse.net/leroy/resume.htm *
*******************************************************
* Leroy Hall *
* 317 Cherokee Drive *
* Loveland, Ohio - USA 45140-2404 *
*******************************************************
they would give you all the hardware if you took it down for them -- doesn't
hurt to ask.
Same drive system used on adjustable beds -- just no position sensor.
Original Message
> Would buying a worm gear drive that would have been using to position
> the old 'C' band satellite be an option? I would think these would be
> pretty cheap, readily available at a Ham Fest and easy to interface to
> the stamp. Just a thought!!
> > You did not mention the size of the dish. The wind load on a dish
> > antenna can be very substantial. Whatever you end up with it will be
> > beefy. Also, this positioning requires the dish be positioned on 2
> > axis, azimuth and elevation.
> >
> > I would not attempt this myself, to many technical and mechanical
> > obstacles. Simply holding the dish in place will require a brake of
> > some kind. Relying on gearing to hold the dish in place is not a good
> > idea, besides, it probably wont work. (Take this from a ham who has
> > been pointing antennas for more than a few years.
> >
> > Whatever you end up with will be more expensive, and possibly less
> > reliable, than an off-the-shelf az-el positioner.
the size of a Direct TV dish. I'm trying to go as simple as I can
here. I know there would be complications in aligning the dish as he
would drive down the road so the dish would not be used until he
stopped.
The idea here is to be able to align the dish electrically instead of
manually.
Frank G.
--- In basicstamps@y..., Rodent <daweasel@s...> wrote:
> What you need is some sort of encoder or similar device to measure
the
> position of the dish. If I remember right, the old C-band dishes
used a
> screw-jack to move the dish and a linear-actuated potentiometer to
measure
> the position.
>
> Keep in mind if you use regular gears you need quite a bit of
reduction to
> keep the dish from turning the motor in a high wind. A worm gear
works well
> for this as it will hold is position.
>
> How big a dish are we talking?
>
>
Original Message
>
> > I want to make a dish positioning system for a friend of mine.
Now I
> > know that I could use modified servo motors. But I am afraid that
> > the servos would be to large and expensive. My other thought was
to
> > use old windshield wiper motors which would be much less expensive
> > than the servos, but I don't know if I can get too accurate with
this
> > type of set up. What do you guys think? Any suggestions would be
> > appreciated.
since it would be hard to find a satellite without being able to preset the
azimuth or elevation. The other position could be found with the onboard
signal strength meter on the receiver.
Since you don't really know which way the van will wind up being pointed,
the elevation would be the part of the position to measure accurately,
assuming you are parked on level ground. A tilt sensor may work well here.
The gross azimuth could be determined with a compass module on the dish,
then tuned with the signal strength meter.
Original Message
> The plan is to set up a dish system on my friends van. The dish is
> the size of a Direct TV dish. I'm trying to go as simple as I can
> here. I know there would be complications in aligning the dish as he
> would drive down the road so the dish would not be used until he
> stopped.
>
> The idea here is to be able to align the dish electrically instead of
> manually.
>The plan is to set up a dish system on my friends van. The dish is
>the size of a Direct TV dish. I'm trying to go as simple as I can
>here. I know there would be complications in aligning the dish as he
>would drive down the road so the dish would not be used until he
>stopped.
>
>The idea here is to be able to align the dish electrically instead of
>manually.
>
>Frank G.
How fast does your friend drive? (grin) ...Wind speeds can exceed
the actual speed of the vehicle in motion relative to the vehicle even
if there is no head-wind. (Not to go into considerable detail, think
of an airplane wing and the aspect that causes lift...air moving over
the top of a car should be slightly faster than air moving under a car
in a similar since of a "wing". While the air moving under the car would
correlate more to the actual speed of the car.)
PLUS since you have now indicated a vehicle... This means that the
disk must have a larger degree of rotation to accommodate for vehicle
orientation at any given time.
I would initially say to use a 2-axis gimbal mechanism, but I am not
sure this would hold up to potential Highway wind speeds...
( 80mph car + 30mph wind gusts ) * 25% safety margin = 130+ mph wind
requirements that must be withstood by your friends vehicle appendage.
Not something I would want to tackle. You would not want me to be
the person behind your friend on the Highway, if something were to
"fall-off". Of course I would not want to be me either. (Ouch!)
Beau Schwabe IC Mask Designer
National Semiconductor Wired Communications Division
500 Pinnacle Court, Suite 525 Mail Stop GA1 Norcross, GA 30071
remember the company name, but it was ment to point a satellite dish on a
van. I wanted it for the bi-directional internet data and apparently it's
not good enough for that ... but it'll handle regular DSS fine.
FWIW,
John
>
Original Message
> From: fwankg@y... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=dOR6InyO9NUq_yJ-ADJsbLIYQ5uSAFc_rdZH6eEo7wvnjQsvxa81krURmKWQVbqxbg3Jyyx7]fwankg@y...[/url
> Sent: Tuesday, July 31, 2001 10:40 AM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Re: to servo or not to servo!
>
>
> The plan is to set up a dish system on my friends van. The dish is
> the size of a Direct TV dish. I'm trying to go as simple as I can
> here. I know there would be complications in aligning the dish as he
> would drive down the road so the dish would not be used until he
> stopped.
>
> The idea here is to be able to align the dish electrically instead of
> manually.
>
> Frank G.
>
>
>
> --- In basicstamps@y..., Rodent <daweasel@s...> wrote:
> > What you need is some sort of encoder or similar device to measure
> the
> > position of the dish. If I remember right, the old C-band dishes
> used a
> > screw-jack to move the dish and a linear-actuated potentiometer to
> measure
> > the position.
> >
> > Keep in mind if you use regular gears you need quite a bit of
> reduction to
> > keep the dish from turning the motor in a high wind. A worm gear
> works well
> > for this as it will hold is position.
> >
> > How big a dish are we talking?
> >
> >
Original Message
> >
> > > I want to make a dish positioning system for a friend of mine.
> Now I
> > > know that I could use modified servo motors. But I am afraid that
> > > the servos would be to large and expensive. My other thought was
> to
> > > use old windshield wiper motors which would be much less expensive
> > > than the servos, but I don't know if I can get too accurate with
> this
> > > type of set up. What do you guys think? Any suggestions would be
> > > appreciated.
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
> Subject and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
and still pick up satellite signals. Probably would be slow to respond
in town <GRIN>. But on long trips down straight roads, it should be
quite do able..
Leroy
fwankg@y... wrote:
>
> The plan is to set up a dish system on my friends van. The dish is
> the size of a Direct TV dish. I'm trying to go as simple as I can
> here. I know there would be complications in aligning the dish as he
> would drive down the road so the dish would not be used until he
> stopped.
>
<snip>
--
*******************************************************
* Leroy Hall *
* 317 Cherokee Drive *
* Loveland, Ohio - USA 45140-2404 *
*******************************************************
* Phone: (513) 697-7539 *
* Cell : (513) 300-8632 *
* Email: leroy@f... *
* Home page URL: http://home.fuse.net/leroy/ *
* Resume URL: http://home.fuse.net/leroy/resume.htm *
*******************************************************
* Leroy Hall *
* 317 Cherokee Drive *
* Loveland, Ohio - USA 45140-2404 *
*******************************************************
much to this, except that I am currently involved in a project
that involves the automated flight of a scale model helicopter.
Which has allowed me to get my feet a little wet concerning
tilt sensors.
If you are interested in a nice tilt sensor, may I suggest that
you consider the ADXL210EB from www.analog.com. It'll set
you back a whole thirty bucks plus shipping. Its easily
readable via the basic stamp. In a nutshell, this is a
really cool device. Its in a surface mount chip. It measures
g force. one g = earth's gravity. i think. Anyway, perhaps
you might look at this. It consists of a really cool new
technology that well, they've figured out how to make really
small mechanical devices. This little chip has some sort
of spring loaded sensor. Tilt it to level and you get one
reading. Tilt it to the left and get another reading.
Tilt to the right and get another. The adxl210 is a dual
axis sensor, but analog.com also has single axis versions
of this chip.
Note that the "EB" in the part number means "evaluation board".
This chip comes in a surface mount type chip, which for an
electronics person with six thumbs like myself they will
sell it to you already mounted to a circuit board that easily
interfaces with the stamp. There is some code on the web for
interfacing with this device, in fact i think that there is
some on the parallax site, but I could be mistaken.
Have a day.
CgiGuy.Com
--- In basicstamps@y..., Rodent <daweasel@s...> wrote:
> Well, one component of the position is gonna require some sort of
feedback
> since it would be hard to find a satellite without being able to
preset the
> azimuth or elevation. The other position could be found with the
onboard
> signal strength meter on the receiver.
>
> Since you don't really know which way the van will wind up being
pointed,
> the elevation would be the part of the position to measure
accurately,
> assuming you are parked on level ground. A tilt sensor may work well
here.
> The gross azimuth could be determined with a compass module on the
dish,
> then tuned with the signal strength meter.
>
>
Original Message
>
> > The plan is to set up a dish system on my friends van. The dish
is
> > the size of a Direct TV dish. I'm trying to go as simple as I can
> > here. I know there would be complications in aligning the dish as
he
> > would drive down the road so the dish would not be used until he
> > stopped.
> >
> > The idea here is to be able to align the dish electrically instead
of
> > manually.
to keep a dish pointed at a satellite while flying -- this was on an AWACS
plane and not a fighter, but cool none the less. They were thinking about
implementing it on commercial airliners for a pay-per-view movie type deal.
Original Message
> With the right calculations, you should be able to drive down the road
> and still pick up satellite signals. Probably would be slow to respond
> in town <GRIN>. But on long trips down straight roads, it should be
> quite do able..
> > The plan is to set up a dish system on my friends van. The dish is
> > the size of a Direct TV dish. I'm trying to go as simple as I can
> > here. I know there would be complications in aligning the dish as he
> > would drive down the road so the dish would not be used until he
> > stopped.
>I remember seeing a thing on TV where they had a system in military aircraft
>to keep a dish pointed at a satellite while flying -- this was on an AWACS
>plane and not a fighter, but cool none the less. They were thinking about
>implementing it on commercial airliners for a pay-per-view movie type deal.
Betcha nickel it was under a radome though... not to mention costing enough
to keep the whole mailing list in STAMPs for the rest of their lives. ;-)
Jim H
yourself. Large servos are used in these units, the stamp would be
ideal for the logical control of the motors.
Rich
--- In basicstamps@y..., "Leroy Hall, Senior" <leroy@f...> wrote:
> Would buying a worm gear drive that would have been using to
position
> the old 'C' band satellite be an option? I would think these would
be
> pretty cheap, readily available at a Ham Fest and easy to interface
to
> the stamp. Just a thought!!
>
>
> Leroy
>
> iceninevt@y... wrote:
> >
> > You did not mention the size of the dish. The wind load on a dish
> > antenna can be very substantial. Whatever you end up with it will
be
> > beefy. Also, this positioning requires the dish be positioned on 2
> > axis, azimuth and elevation.
> >
> > I would not attempt this myself, to many technical and mechanical
> > obstacles. Simply holding the dish in place will require a brake
of
> > some kind. Relying on gearing to hold the dish in place is not a
good
> > idea, besides, it probably wont work. (Take this from a ham who
has
> > been pointing antennas for more than a few years.
> >
> > Whatever you end up with will be more expensive, and possibly less
> > reliable, than an off-the-shelf az-el positioner.
> >
> > Regards
> >
> > Rich
> >
> > --- In basicstamps@y..., fwankg@y... wrote:
> > > Okay guys, here is goes.
> > >
> > > I want to make a dish positioning system for a friend of mine.
Now
> > I
> > > know that I could use modified servo motors. But I am afraid
that
> > > the servos would be to large and expensive. My other thought
was
> > to
> > > use old windshield wiper motors which would be much less
expensive
> > > than the servos, but I don't know if I can get too accurate with
> > this
> > > type of set up. What do you guys think? Any suggestions would
be
> > > appreciated.
> > >
> > > Thanks in advance!!
> > >
> > > Frank G.
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@y...
> > from the same email address that you subscribed. Text in the
Subject and Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
>
> --
>
> *******************************************************
> * Leroy Hall *
> * 317 Cherokee Drive *
> * Loveland, Ohio - USA 45140-2404 *
> *******************************************************
> * Phone: (513) 697-7539 *
> * Cell : (513) 300-8632 *
> * Email: leroy@f... *
> * Home page URL: http://home.fuse.net/leroy/ *
> * Resume URL: http://home.fuse.net/leroy/resume.htm *
> *******************************************************
> * Leroy Hall *
> * 317 Cherokee Drive *
> * Loveland, Ohio - USA 45140-2404 *
> *******************************************************
to the servo. Ballpark az-el information would be required. AGC
voltages in the receiver could be pumped through ADC's. Armed with
this info the microcontroller could move the dish to attain max
signal.
I would consider this to be (for me anyway) a very ambitious project.
Rich
--- In basicstamps@y..., Rodent <daweasel@s...> wrote:
> Well, one component of the position is gonna require some sort of
feedback
> since it would be hard to find a satellite without being able to
preset the
> azimuth or elevation. The other position could be found with the
onboard
> signal strength meter on the receiver.
>
> Since you don't really know which way the van will wind up being
pointed,
> the elevation would be the part of the position to measure
accurately,
> assuming you are parked on level ground. A tilt sensor may work
well here.
> The gross azimuth could be determined with a compass module on the
dish,
> then tuned with the signal strength meter.
>
>
Original Message
>
> > The plan is to set up a dish system on my friends van. The dish
is
> > the size of a Direct TV dish. I'm trying to go as simple as I can
> > here. I know there would be complications in aligning the dish
as he
> > would drive down the road so the dish would not be used until he
> > stopped.
> >
> > The idea here is to be able to align the dish electrically
instead of
> > manually.
> costing enough
> to keep the whole mailing list in STAMPs for the rest of their lives. ;-)
Speaking of that, the commercial version I saw was under a dome (I assume to
protect from winds). It might be worth holding a sheet of plexiglass in
front of a DSS dish to see if it affects the reception.
FWIW
John
> Never having worked with satellite dishes, I cant really add
> much to this, except that I am currently involved in a project
> that involves the automated flight of a scale model helicopter.
> Which has allowed me to get my feet a little wet concerning
> tilt sensors.
>
> If you are interested in a nice tilt sensor, may I suggest that
> you consider the ADXL210EB from www.analog.com. It'll set
> you back a whole thirty bucks plus shipping. Its easily
> readable via the basic stamp. In a nutshell, this is a
> really cool device. Its in a surface mount chip. It measures
> g force. one g = earth's gravity. i think. Anyway, perhaps
> you might look at this. It consists of a really cool new
> technology that well, they've figured out how to make really
> small mechanical devices. This little chip has some sort
> of spring loaded sensor. Tilt it to level and you get one
> reading. Tilt it to the left and get another reading.
> Tilt to the right and get another. The adxl210 is a dual
> axis sensor, but analog.com also has single axis versions
> of this chip.
>
> Note that the "EB" in the part number means "evaluation board".
> This chip comes in a surface mount type chip, which for an
> electronics person with six thumbs like myself they will
> sell it to you already mounted to a circuit board that easily
> interfaces with the stamp. There is some code on the web for
> interfacing with this device, in fact i think that there is
> some on the parallax site, but I could be mistaken.
>
> Have a day.
>
> CgiGuy.Com
>
> --- In basicstamps@y..., Rodent <daweasel@s...> wrote:
> > Well, one component of the position is gonna require some sort of
> feedback
> > since it would be hard to find a satellite without being able to
> preset the
> > azimuth or elevation. The other position could be found with the
> onboard
> > signal strength meter on the receiver.
> >
> > Since you don't really know which way the van will wind up being
> pointed,
> > the elevation would be the part of the position to measure
> accurately,
> > assuming you are parked on level ground. A tilt sensor may work well
> here.
> > The gross azimuth could be determined with a compass module on the
> dish,
> > then tuned with the signal strength meter.
> >
> >
Original Message
> >
> > > The plan is to set up a dish system on my friends van. The dish
> is
> > > the size of a Direct TV dish. I'm trying to go as simple as I can
> > > here. I know there would be complications in aligning the dish as
> he
> > > would drive down the road so the dish would not be used until he
> > > stopped.
> > >
> > > The idea here is to be able to align the dish electrically instead
> of
> > > manually.
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/