Homebrew_PCBs

Hi Guys,

I've been following the pcb driller discussion. I've been wanting to
build one for a long time. But so far the designs seem too complicated
or too heavy duty for my needs. And too expensive too. I want to throw
out a couple of ideas. I'd appreciate any thoughts on them. (Yes,
Stefan, I wouldd like yur thoughts too, as long as they don't include
anything about a chicken grill. :)

I use EAGLE free version for my boards. That means they are under 3" x
4". When drawing the layout, I set EAGLE at a 0.10" grid (sometimes I
cheat and go 0.05"). I lay out my components to fit this grid. This
works well, but I don't like to manually postion the board for driling
on my drill press.

It occurred to me that what I needed was something that could drill
holes on a 3" x 4" grid. At 0.10" spacing the grid would be 30 by 40,
and on 0.05" spacing the grid would be 60 x 80.

I will say, for now, I am not interested in milling, just drilling
holes. And I would be willing to "pull the handle" on the drill press.
My boards are small enough with not too many holes. So what would it
take to build a grid based driller.

My first thought was converting an old printer. Attaching a small
dremel to the print head. I would move the print head across the page
stoping at the appropriate spot and the pulls the handle. Afte all the
holes on one line were drilled, go to the next line. After all if you
cn print a grid of dots on a page, you could move the print heaad with
simple commands.

The second idea I had, after looking at all the drivers chps and
software and discussion about half stepping and choppers, was that the
driller could be very light duty due to the size of the board and the
coarseness of the steps.

Looking at the old Nasa stepper design, that uses 2 flip flops and a
couple of nor gates, I realized that 2 lines would be all that i
really need for single stepping.

I've been playing woth the PICAXE chips. They are programmed in basic
and only need a 3 wire cable for programming. Best of all they (the
08M)are only about $3 each, and has 5 i/o lines.

I've been thinking about using one of these as the controller. If I
download the coordinate of the holes, program, The PICAXE could
convert the coordinates to steps I could position the drill using just
4 of the 5 lines. The 5th line would be an input to start or go to the
next holes. A driver chip or transistors would be needed for the power
to run the servovs.

For the driller bed, a light duty X-Y table about 6" x 6" could be
driven by some small servos and screws.

It would be a small, inexpensive, semi automatic pcb driller.

What do you see as the pitfalls with these two ideas?

Myc

1st: if Eagle doesn't produce a DRILL file, chuck it, I can't remember if it
does.

2nd: if you are going to go into programming, might as well follow the
conventional technique using steppers, that way you can copy existing code,
same thing for the stepper motor control circuits.

3rd: you can use the same technique as the others, but drastically reduce in
size everything, that in itself will make a LOT of things easier, for
example, a 12" rod of aluminium 1/4" thick will be plenty for you. Same
thing with the screw, a 1/4" diameter screw would be fine.

4th: make it all out of wood, REAL easy to cut & drill, using holes in the
wood as bushings for the rods.

5th: polish the aluminium rods slightly, just to give them that extra shine,
which translates into less friction (maybe a little dab of lubricant).


Myc, I've looked at a lot of ways to skin this chicken, and if you have a
DRILL file, can program PICs, can download the file, can assemble a basic
stepper controller like this one:
<http://www.xavierkamial.com/Videos/Stepper%20Motor%20Controller.htm>, then
steppers are the way to go.

Everything is out there for a rinky-dink system, I am just looking for
something with a little more ooomph. But for drilling, el-cheapo steppers
cost no more than $5. Using servos, you'd be all alone in left field, with
probably no samples from the web to get ideas from. With steppers, you'd
get pretty darn close to the same precision as a lot of us will get. The
only difference is that we will be able to maintain that precision over a
longer surface; which you don't need anyways.

Robert
:)



-----Message d'origine-----
De : Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] De
la part de mycroft2152
Envoyé : juin 11 2005 20:10
À : Homebrew_PCBs@yahoogroups.com
Objet : [Homebrew_PCBs] PCB Driller - Looking for comments


Hi Guys,

I've been following the pcb driller discussion. I've been wanting to
build one for a long time. But so far the designs seem too complicated
or too heavy duty for my needs. And too expensive too. I want to throw
out a couple of ideas. I'd appreciate any thoughts on them. (Yes,
Stefan, I wouldd like yur thoughts too, as long as they don't include
anything about a chicken grill. :)

I use EAGLE free version for my boards. That means they are under 3" x
4". When drawing the layout, I set EAGLE at a 0.10" grid (sometimes I
cheat and go 0.05"). I lay out my components to fit this grid. This
works well, but I don't like to manually postion the board for driling
on my drill press.

It occurred to me that what I needed was something that could drill
holes on a 3" x 4" grid. At 0.10" spacing the grid would be 30 by 40,
and on 0.05" spacing the grid would be 60 x 80.

I will say, for now, I am not interested in milling, just drilling
holes. And I would be willing to "pull the handle" on the drill press.
My boards are small enough with not too many holes. So what would it
take to build a grid based driller.

My first thought was converting an old printer. Attaching a small
dremel to the print head. I would move the print head across the page
stoping at the appropriate spot and the pulls the handle. Afte all the
holes on one line were drilled, go to the next line. After all if you
cn print a grid of dots on a page, you could move the print heaad with
simple commands.

The second idea I had, after looking at all the drivers chps and
software and discussion about half stepping and choppers, was that the
driller could be very light duty due to the size of the board and the
coarseness of the steps.

Looking at the old Nasa stepper design, that uses 2 flip flops and a
couple of nor gates, I realized that 2 lines would be all that i
really need for single stepping.

I've been playing woth the PICAXE chips. They are programmed in basic
and only need a 3 wire cable for programming. Best of all they (the
08M)are only about $3 each, and has 5 i/o lines.

I've been thinking about using one of these as the controller. If I
download the coordinate of the holes, program, The PICAXE could
convert the coordinates to steps I could position the drill using just
4 of the 5 lines. The 5th line would be an input to start or go to the
next holes. A driver chip or transistors would be needed for the power
to run the servovs.

For the driller bed, a light duty X-Y table about 6" x 6" could be
driven by some small servos and screws.

It would be a small, inexpensive, semi automatic pcb driller.

What do you see as the pitfalls with these two ideas?

Myc







Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBs

If Files or Photos are running short of space, post them here:
http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
Yahoo! Groups Links

On Saturday 11 June 2005 08:10 pm, mycroft2152 wrote:

> My first thought was converting an old printer. Attaching a small dremel to
> the print head. I would move the print head across the page stoping at the
> appropriate spot and the pulls the handle. Afte all the holes on one line
> were drilled, go to the next line. After all if you cn print a grid of dots
> on a page, you could move the print heaad with simple commands.

If you're talking about the use of the hardware platform, and maybe the
circuitry to drive it with, giving it your own commands rather than relying
on the logic in the printer, you might be able to make this work. Biggest
problem I see is that the mass of any dremel is going to likely be *way* more
than that of any printhead, unless you're talking about a really old
printer. I have a couple of those in storage presently awaiting their turn
to be scrapped, but I don't expect that they're especially common these
days, and the newer stuff uses as little material as they can possibly get
away with, including much smaller motors.

Dunno what you mean by "a small dremel", they all seem to be pretty much the
same size to me. And the mass of moving that is where you may run into
trouble. Way more than just a print head. So in addition to slowing down
compared to the speed of a print head, you'll probably want to modify those
components as well.

> The second idea I had, after looking at all the drivers chps and
> software and discussion about half stepping and choppers, was that the
> driller could be very light duty due to the size of the board and the
> coarseness of the steps.
>
> Looking at the old Nasa stepper design, that uses 2 flip flops and a
> couple of nor gates, I realized that 2 lines would be all that i
> really need for single stepping.

That sounds like the design that I'm probably going to end up with here for
any number of things.

Hi Roy,

By a small dremel, i was thinking of either the handpiece extension
or the little battery powered dremel. Since this in a light duty
machine, the battery version could work.

I agree that modern printers are moving very small masses with the
ink jet print heads, but i have a couple of very old massive
printers, one is a daisy wheel type, the other is a wide carriage
dot matrix. Both used a ribbon.

The idea came from the old days of drawing with ASCII characters
uning the Print command in Basic.

Myc


--- In Homebrew_PCBs@yahoogroups.com, "Roy J. Tellason"
<rtellason@b...> wrote:

> On Saturday 11 June 2005 08:10 pm, mycroft2152 wrote:
>
> > My first thought was converting an old printer. Attaching a

small dremel to

> > the print head. I would move the print head across the page

stoping at the

> > appropriate spot and the pulls the handle. Afte all the holes on

one line

> > were drilled, go to the next line. After all if you cn print a

grid of dots

> > on a page, you could move the print heaad with simple commands.
>
> If you're talking about the use of the hardware platform, and

maybe the

> circuitry to drive it with, giving it your own commands rather

than relying

> on the logic in the printer, you might be able to make this

work. Biggest

> problem I see is that the mass of any dremel is going to likely be

*way* more

> than that of any printhead, unless you're talking about a really

old

> printer. I have a couple of those in storage presently awaiting

their turn

> to be scrapped, but I don't expect that they're especially common

these

> days, and the newer stuff uses as little material as they can

possibly get

> away with, including much smaller motors.
>
> Dunno what you mean by "a small dremel", they all seem to be

pretty much the

> same size to me. And the mass of moving that is where you may run

into

> trouble. Way more than just a print head. So in addition to

slowing down

> compared to the speed of a print head, you'll probably want to

modify those

> components as well.
>
> > The second idea I had, after looking at all the drivers chps and
> > software and discussion about half stepping and choppers, was

that the

> > driller could be very light duty due to the size of the board

and the

> > coarseness of the steps.
> >
> > Looking at the old Nasa stepper design, that uses 2 flip flops

and a

> > couple of nor gates, I realized that 2 lines would be all that i
> > really need for single stepping.
>
> That sounds like the design that I'm probably going to end up with

here for

> any number of things.

Hi Robert,

Thanks for the encouragement. Yes, I looking for a "rinky dink"
system. It fits my basic needs.

Thanks for the link, on the stepper driver. I had seen it previously
and that is what got me thinking that the 8 pin PICAXE with 5 i/o's
might do the job. I understood from that write up, that for single
stepping it took just 4 2 bit numbers along with a couple of
inverters.

For single stepping the two lines can be used for each of the
motors. By adding an inverter to these lines you get the 4 lines
needed for the steppers. Since for single stepping they always are
inverted.

The PICAXE website has schematics for this type of circuit. It uses
a 2003 or 2803 for the low power drivers, with the spare gates used
as inverters. It also has the short program to output the 2 bit
pattern to drive the steppers in single step mod.

The 8 pin 3 dolalar picaxe could work for a small number of holes,
fur to its limited memory. But the 18 pin 18X version (about 10
bucks) has more memory and enough i/o pin to drive all 8 lines, thus
voiding the need for the inverters.

The key here is the simplicity and light framework needed, thus the
low cost. The trade offs include preplanning the layout and loading
the coordinates into the Picaxe program before downloading. But once
its done, you have permanent drill file.

Bu using one i/o line for start, goto next hole, a pc is not needed
to run the program. the PICAXE would be all that is necessary. For 3
bucks, yo could keep each drill program on a chip and change chips
when needed.

There would be some initial calculations to get the stepper's
rotation converteed to linear values, but I don't think that shuld
be too bad.

Thanks again,

Myc




--- In Homebrew_PCBs@yahoogroups.com, Robert Hedan
<robert.hedan@v...> wrote:

> 1st: if Eagle doesn't produce a DRILL file, chuck it, I can't

remember if it

> does.
>
> 2nd: if you are going to go into programming, might as well follow

the

> conventional technique using steppers, that way you can copy

existing code,

> same thing for the stepper motor control circuits.
>
> 3rd: you can use the same technique as the others, but drastically

reduce in

> size everything, that in itself will make a LOT of things easier,

for

> example, a 12" rod of aluminium 1/4" thick will be plenty for

you. Same

> thing with the screw, a 1/4" diameter screw would be fine.
>
> 4th: make it all out of wood, REAL easy to cut & drill, using

holes in the

> wood as bushings for the rods.
>
> 5th: polish the aluminium rods slightly, just to give them that

extra shine,

> which translates into less friction (maybe a little dab of

lubricant).

>
>
> Myc, I've looked at a lot of ways to skin this chicken, and if you

have a

> DRILL file, can program PICs, can download the file, can assemble

a basic

> stepper controller like this one:
> <http://www.xavierkamial.com/Videos/Stepper%20Motor%

20Controller.htm>, then

> steppers are the way to go.
>
> Everything is out there for a rinky-dink system, I am just looking

for

> something with a little more ooomph. But for drilling, el-cheapo

steppers

> cost no more than $5. Using servos, you'd be all alone in left

field, with

> probably no samples from the web to get ideas from. With

steppers, you'd

> get pretty darn close to the same precision as a lot of us will

get. The

> only difference is that we will be able to maintain that precision

over a

> longer surface; which you don't need anyways.
>
> Robert
> :)
>
>
>
> -----Message d'origine-----
> De : Homebrew_PCBs@yahoogroups.com

[mailto:Homebrew_PCBs@yahoogroups.com] De

> la part de mycroft2152
> Envoyé : juin 11 2005 20:10
> À : Homebrew_PCBs@yahoogroups.com
> Objet : [Homebrew_PCBs] PCB Driller - Looking for comments
>
>
> Hi Guys,
>
> I've been following the pcb driller discussion. I've been wanting

to

> build one for a long time. But so far the designs seem too

complicated

> or too heavy duty for my needs. And too expensive too. I want to

throw

> out a couple of ideas. I'd appreciate any thoughts on them. (Yes,
> Stefan, I wouldd like yur thoughts too, as long as they don't

include

> anything about a chicken grill. :)
>
> I use EAGLE free version for my boards. That means they are under

3" x

> 4". When drawing the layout, I set EAGLE at a 0.10" grid

(sometimes I

> cheat and go 0.05"). I lay out my components to fit this grid.

This

> works well, but I don't like to manually postion the board for

driling

> on my drill press.
>
> It occurred to me that what I needed was something that could

drill

> holes on a 3" x 4" grid. At 0.10" spacing the grid would be 30 by

40,

> and on 0.05" spacing the grid would be 60 x 80.
>
> I will say, for now, I am not interested in milling, just drilling
> holes. And I would be willing to "pull the handle" on the drill

press.

> My boards are small enough with not too many holes. So what would

it

> take to build a grid based driller.
>
> My first thought was converting an old printer. Attaching a small
> dremel to the print head. I would move the print head across the

page

> stoping at the appropriate spot and the pulls the handle. Afte all

the

> holes on one line were drilled, go to the next line. After all if

you

> cn print a grid of dots on a page, you could move the print heaad

with

> simple commands.
>
> The second idea I had, after looking at all the drivers chps and
> software and discussion about half stepping and choppers, was that

the

> driller could be very light duty due to the size of the board and

the

> coarseness of the steps.
>
> Looking at the old Nasa stepper design, that uses 2 flip flops and

a

> couple of nor gates, I realized that 2 lines would be all that i
> really need for single stepping.
>
> I've been playing woth the PICAXE chips. They are programmed in

basic

> and only need a 3 wire cable for programming. Best of all they

(the

> 08M)are only about $3 each, and has 5 i/o lines.
>
> I've been thinking about using one of these as the controller. If

I

> download the coordinate of the holes, program, The PICAXE could
> convert the coordinates to steps I could position the drill using

just

> 4 of the 5 lines. The 5th line would be an input to start or go to

the

> next holes. A driver chip or transistors would be needed for the

power

> to run the servovs.
>
> For the driller bed, a light duty X-Y table about 6" x 6" could be
> driven by some small servos and screws.
>
> It would be a small, inexpensive, semi automatic pcb driller.
>
> What do you see as the pitfalls with these two ideas?
>
> Myc
>
>
>
>
>
>
>
> Be sure to visit the group home and check for new Links, Files,

and Photos:

> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links

Hi robert,

Hadn't thought of using servos for this, just steppers. But that is
an interseting idea. For hobby robots, the servos are modified for
continuous rotation. May just be possible.

The picaxe has built in servo routines and is programmed in BASIC.
Should be easy to hook up a couple of servos to the screws to try it
out.

Myc


--- In Homebrew_PCBs@yahoogroups.com, Robert Hedan
<robert.hedan@v...> wrote:

> 1st: if Eagle doesn't produce a DRILL file, chuck it, I can't

remember if it

> does.
>
> 2nd: if you are going to go into programming, might as well follow

the

> conventional technique using steppers, that way you can copy

existing code,

> same thing for the stepper motor control circuits.
>
> 3rd: you can use the same technique as the others, but drastically

reduce in

> size everything, that in itself will make a LOT of things easier,

for

> example, a 12" rod of aluminium 1/4" thick will be plenty for

you. Same

> thing with the screw, a 1/4" diameter screw would be fine.
>
> 4th: make it all out of wood, REAL easy to cut & drill, using

holes in the

> wood as bushings for the rods.
>
> 5th: polish the aluminium rods slightly, just to give them that

extra shine,

> which translates into less friction (maybe a little dab of

lubricant).

>
>
> Myc, I've looked at a lot of ways to skin this chicken, and if you

have a

> DRILL file, can program PICs, can download the file, can assemble

a basic

> stepper controller like this one:
> <http://www.xavierkamial.com/Videos/Stepper%20Motor%

20Controller.htm>, then

> steppers are the way to go.
>
> Everything is out there for a rinky-dink system, I am just looking

for

> something with a little more ooomph. But for drilling, el-cheapo

steppers

> cost no more than $5. Using servos, you'd be all alone in left

field, with

> probably no samples from the web to get ideas from. With

steppers, you'd

> get pretty darn close to the same precision as a lot of us will

get. The

> only difference is that we will be able to maintain that precision

over a

> longer surface; which you don't need anyways.
>
> Robert
> :)
>
>
>
> -----Message d'origine-----
> De : Homebrew_PCBs@yahoogroups.com

[mailto:Homebrew_PCBs@yahoogroups.com] De

> la part de mycroft2152
> Envoyé : juin 11 2005 20:10
> À : Homebrew_PCBs@yahoogroups.com
> Objet : [Homebrew_PCBs] PCB Driller - Looking for comments
>
>
> Hi Guys,
>
> I've been following the pcb driller discussion. I've been wanting

to

> build one for a long time. But so far the designs seem too

complicated

> or too heavy duty for my needs. And too expensive too. I want to

throw

> out a couple of ideas. I'd appreciate any thoughts on them. (Yes,
> Stefan, I wouldd like yur thoughts too, as long as they don't

include

> anything about a chicken grill. :)
>
> I use EAGLE free version for my boards. That means they are under

3" x

> 4". When drawing the layout, I set EAGLE at a 0.10" grid

(sometimes I

> cheat and go 0.05"). I lay out my components to fit this grid.

This

> works well, but I don't like to manually postion the board for

driling

> on my drill press.
>
> It occurred to me that what I needed was something that could

drill

> holes on a 3" x 4" grid. At 0.10" spacing the grid would be 30 by

40,

> and on 0.05" spacing the grid would be 60 x 80.
>
> I will say, for now, I am not interested in milling, just drilling
> holes. And I would be willing to "pull the handle" on the drill

press.

> My boards are small enough with not too many holes. So what would

it

> take to build a grid based driller.
>
> My first thought was converting an old printer. Attaching a small
> dremel to the print head. I would move the print head across the

page

> stoping at the appropriate spot and the pulls the handle. Afte all

the

> holes on one line were drilled, go to the next line. After all if

you

> cn print a grid of dots on a page, you could move the print heaad

with

> simple commands.
>
> The second idea I had, after looking at all the drivers chps and
> software and discussion about half stepping and choppers, was that

the

> driller could be very light duty due to the size of the board and

the

> coarseness of the steps.
>
> Looking at the old Nasa stepper design, that uses 2 flip flops and

a

> couple of nor gates, I realized that 2 lines would be all that i
> really need for single stepping.
>
> I've been playing woth the PICAXE chips. They are programmed in

basic

> and only need a 3 wire cable for programming. Best of all they

(the

> 08M)are only about $3 each, and has 5 i/o lines.
>
> I've been thinking about using one of these as the controller. If

I

> download the coordinate of the holes, program, The PICAXE could
> convert the coordinates to steps I could position the drill using

just

> 4 of the 5 lines. The 5th line would be an input to start or go to

the

> next holes. A driver chip or transistors would be needed for the

power

> to run the servovs.
>
> For the driller bed, a light duty X-Y table about 6" x 6" could be
> driven by some small servos and screws.
>
> It would be a small, inexpensive, semi automatic pcb driller.
>
> What do you see as the pitfalls with these two ideas?
>
> Myc
>
>
>
>
>
>
>
> Be sure to visit the group home and check for new Links, Files,

and Photos:

> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links

On Sun, 12 Jun 2005 15:28:51 +0200, mycroft2152 <mycroft2152@...>
wrote:

> Hi robert,
> Hadn't thought of using servos for this, just steppers. But that is
> an interseting idea. For hobby robots, the servos are modified for
> continuous rotation. May just be possible.
> The picaxe has built in servo routines and is programmed in BASIC.
> Should be easy to hook up a couple of servos to the screws to try it
> out.
> Myc

I thing the reference to servos was meant more general, not RC model
servos.
They often use DC servo motors on larger CNC machines, for faster speeds
and more power.
There is a severe increase in control circuit complexity (you need
rotational feedback and a closed loop control).

If you do not need to advantages of servos (power and speed) it is MUCH
easier to go the well tried route of using steppers.

RC servos would not last very long, in this application, and would not
move very fast or with any amount of force. They are more expensive than
steppers with no advantages, so i would not suggest using them.

Now.... you could use a chicken grill motor..... ;-) just joking!


ST

On Sunday 12 June 2005 09:01 am, mycroft2152 wrote:

> Hi Roy,
>
> By a small dremel, i was thinking of either the handpiece extension or the
> little battery powered dremel. Since this in a light duty machine, the
> battery version could work.

I don't think I've ever seen the battery version, but then I don't get out
shopping much like I used to. :-)

> I agree that modern printers are moving very small masses with the ink jet
> print heads, but i have a couple of very old massive printers, one is a
> daisy wheel type, the other is a wide carriage dot matrix. Both used a
> ribbon.

Yeah, the old daisywheel type printers would definitely get you some useful
stuff. I scrapped one of those, and have two more sitting in storage,
though one is technically a "thimble" printer rather than a daisywheel, an
NEC "Spinwriter". I look forward to getting some useful stuff out of those
when the time comes.

> The idea came from the old days of drawing with ASCII characters
> uning the Print command in Basic.

Heh. :-)

On Sunday 12 June 2005 10:37 am, Stefan Trethan wrote:

> On Sun, 12 Jun 2005 15:28:51 +0200, mycroft2152 <mycroft2152@...>
>
> wrote:
> > Hi robert,
> > Hadn't thought of using servos for this, just steppers. But that is
> > an interseting idea. For hobby robots, the servos are modified for
> > continuous rotation. May just be possible.
> > The picaxe has built in servo routines and is programmed in BASIC.
> > Should be easy to hook up a couple of servos to the screws to try it
> > out.
> > Myc
>
> I thing the reference to servos was meant more general, not RC model
> servos.
> They often use DC servo motors on larger CNC machines, for faster speeds
> and more power.
> There is a severe increase in control circuit complexity (you need
> rotational feedback and a closed loop control).

I believe that some of the motors I have salvaged are servo motors -- there
being only two wires instead of the usually larger number for steppers, and
also the encoder on one side gives it away. :-)

> If you do not need to advantages of servos (power and speed) it is MUCH
> easier to go the well tried route of using steppers.

Which is why I plan to use those first!

> RC servos would not last very long, in this application, and would not
> move very fast or with any amount of force. They are more expensive than
> steppers with no advantages, so i would not suggest using them.

To some people those _are_ "servos", the term having been distorted into tha
context, I guess.

Hi Roy,

My more modern inkjet has the head driven by a 2 wire
motor, and rides along a clear plastic encoder strip
with black lines for feedback.

I was thinking along the lines od a hobby servo that
was modified for continuous rotation.

Since I'm building a light duty xY table, it might be
powerful enough. Some of the mini sumo's can bush a
brick. As for as cost goes, I've got a couple in my
junk box if I want to try them out.

Myc



--- "Roy J. Tellason" <rtellason@...> wrote:

> On Sunday 12 June 2005 10:37 am, Stefan Trethan
> wrote:
> > On Sun, 12 Jun 2005 15:28:51 +0200, mycroft2152
> <mycroft2152@...>
> >
> > wrote:
> > > Hi robert,
> > > Hadn't thought of using servos for this, just
> steppers. But that is
> > > an interseting idea. For hobby robots, the
> servos are modified for
> > > continuous rotation. May just be possible.
> > > The picaxe has built in servo routines and is
> programmed in BASIC.
> > > Should be easy to hook up a couple of servos to
> the screws to try it
> > > out.
> > > Myc
> >
> > I thing the reference to servos was meant more
> general, not RC model
> > servos.
> > They often use DC servo motors on larger CNC
> machines, for faster speeds
> > and more power.
> > There is a severe increase in control circuit
> complexity (you need
> > rotational feedback and a closed loop control).
>
> I believe that some of the motors I have salvaged
> are servo motors -- there
> being only two wires instead of the usually larger
> number for steppers, and
> also the encoder on one side gives it away. :-)
>
> > If you do not need to advantages of servos (power
> and speed) it is MUCH
> > easier to go the well tried route of using
> steppers.
>
> Which is why I plan to use those first!
>
> > RC servos would not last very long, in this
> application, and would not
> > move very fast or with any amount of force. They
> are more expensive than
> > steppers with no advantages, so i would not
> suggest using them.
>
> To some people those _are_ "servos", the term
> having been distorted into tha
> context, I guess.
>
>
>
>
>
>
>
>
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On Sun, 12 Jun 2005 19:33:03 +0200, Roy J. Tellason
<rtellason@...> wrote:

> To some people those _are_ "servos", the term having been distorted
> into tha
> context, I guess.

not really, those people just don't know.

ST