suitable motor for small motorized platform?

[Bill Proms]

I have a small platform that has a pocket videocamera attached to it.
Since I have the camera and platform in a remote location, I need to be
able to move the camera slightly in two dirctions: toward and away from
an external lens (the lens is not attached and focus is done by moving
the camera toward or away from the lens) and also slightly in
perpendicular directions to and fro (because some objects are not
centered in the lens and the camera can move slightly to compensate).

I first tried making two small stacked platforms on top of modified
drawer sliders with strings attached. The idea was to pull a string to
move the camera in either of the directions above, but there is too much
stress needed to get the camera to move and I must find a better way.

Then the idea has occurred to attach a nut to the bottom of each
platform and then use a threaded rod with a motor attached to the rod to
move the platform in either direction. Since the camera needs to be
able to move slowly in any of the directions and go forward and reverse,
I'm not sure what type of motor would be suitable. I have some 3 Volt
DC hobby motors, but I think these are way too fast for the job plus I
doubt they reverse direction with polarity change. Can someone suggest
a suitable motor, preferably something surplus? BTW, the threaded rod
wouldn't need to be anything larger than 1/4" diameter or so.

Thanks,
Bill

 

[mpm]

I have a small platform that has a pocket videocamera attached to it.

Since I have the camera and platform in a remote location, I need to be

able to move the camera slightly in two dirctions: toward and away from

an external lens (the lens is not attached and focus is done by moving

the camera toward or away from the lens) and also slightly in

perpendicular directions to and fro (because some objects are not

centered in the lens and the camera can move slightly to compensate).



I first tried making two small stacked platforms on top of modified

drawer sliders with strings attached. The idea was to pull a string to

move the camera in either of the directions above, but there is too much

stress needed to get the camera to move and I must find a better way.



Then the idea has occurred to attach a nut to the bottom of each

platform and then use a threaded rod with a motor attached to the rod to

move the platform in either direction. Since the camera needs to be

able to move slowly in any of the directions and go forward and reverse,

I'm not sure what type of motor would be suitable. I have some 3 Volt

DC hobby motors, but I think these are way too fast for the job plus I

doubt they reverse direction with polarity change. Can someone suggest

a suitable motor, preferably something surplus? BTW, the threaded rod

wouldn't need to be anything larger than 1/4" diameter or so.



Thanks,

Bill

Perhaps you can adapt something like this: (?)
Link: http://reallyrightstuff.com/Product...0&eq=&desc=B150-B:-Macro-focusing-rail&key=it

 

[Martin Brown]

I have a small platform that has a pocket videocamera attached to it.
Since I have the camera and platform in a remote location, I need to be
able to move the camera slightly in two dirctions: toward and away from
an external lens (the lens is not attached and focus is done by moving
the camera toward or away from the lens) and also slightly in
perpendicular directions to and fro (because some objects are not
centered in the lens and the camera can move slightly to compensate).

I first tried making two small stacked platforms on top of modified
drawer sliders with strings attached. The idea was to pull a string to
move the camera in either of the directions above, but there is too much
stress needed to get the camera to move and I must find a better way.

Then the idea has occurred to attach a nut to the bottom of each
platform and then use a threaded rod with a motor attached to the rod to
move the platform in either direction. Since the camera needs to be
able to move slowly in any of the directions and go forward and reverse,
I'm not sure what type of motor would be suitable. I have some 3 Volt
DC hobby motors, but I think these are way too fast for the job plus I

Gearing the motor speed down is sensible anyway.

doubt they reverse direction with polarity change. Can someone suggest
a suitable motor, preferably something surplus? BTW, the threaded rod
wouldn't need to be anything larger than 1/4" diameter or so.

That makes me wonder just how big and heavy your "small" camera platform
is and what load it has to move around.

You might be able to do what you want with fairly standard radio control
servo motors combined with an optical feedback. Otherwise look at the
platforms for 3D printer beds for inspiration...

 

[Spehro Pefhany]

I have a small platform that has a pocket videocamera attached to it.
Since I have the camera and platform in a remote location, I need to be
able to move the camera slightly in two dirctions: toward and away from
an external lens (the lens is not attached and focus is done by moving
the camera toward or away from the lens) and also slightly in
perpendicular directions to and fro (because some objects are not
centered in the lens and the camera can move slightly to compensate).

I first tried making two small stacked platforms on top of modified
drawer sliders with strings attached. The idea was to pull a string to
move the camera in either of the directions above, but there is too much
stress needed to get the camera to move and I must find a better way.

Then the idea has occurred to attach a nut to the bottom of each
platform and then use a threaded rod with a motor attached to the rod to
move the platform in either direction. Since the camera needs to be
able to move slowly in any of the directions and go forward and reverse,
I'm not sure what type of motor would be suitable. I have some 3 Volt
DC hobby motors, but I think these are way too fast for the job plus I
doubt they reverse direction with polarity change. Can someone suggest
a suitable motor, preferably something surplus? BTW, the threaded rod
wouldn't need to be anything larger than 1/4" diameter or so.

Thanks,
Bill

You can find 4096 steps-per-revolution steppers on eBay for a few
dollars shipped (internal gear reduction). 5mm diameter flatted
shafts. I'm using them to build a 'barn door' DSLR mount to photograph
the night sky. The 4096 is based on half-steps, BTW. You can also find
proper couplers which allows some lack of axial alignment, or just use
a bit of rubber hose.



Best regards,
Spehro Pefhany

 

[Jasen Betts]

Then the idea has occurred to attach a nut to the bottom of each
platform and then use a threaded rod with a motor attached to the rod to
move the platform in either direction. Since the camera needs to be
able to move slowly in any of the directions and go forward and reverse,
I'm not sure what type of motor would be suitable. I have some 3 Volt
DC hobby motors, but I think these are way too fast for the job plus I
doubt they reverse direction with polarity change. Can someone suggest
a suitable motor, preferably something surplus? BTW, the threaded rod
wouldn't need to be anything larger than 1/4" diameter or so.

It sounds like you want motors with gearboxes, AKA gearmotors.
most small DC brushmotors reverse with reversed polarity many that
don't can easily be modified to reverse

 

[Spehro Pefhany]

It sounds like you want motors with gearboxes, AKA gearmotors.
most small DC brushmotors reverse with reversed polarity many that
don't can easily be modified to reverse

Any permanent magnet DC motor should reverse with reverse polarity
input. Small DC motors tend strongly to be PM type.

 

[Bill Proms]

Thanks to all for the responses so far. You certainly have given me
plenty of ideas. To give you an idea of what I have now, take a look at
this:

http://goo.gl/N1Qqq

I don't have this. I fashioned something out of wood and used drawer
sliders, cut way down, for each slid-able axis. If I want to move in
either x-x or y-y, I just pull the appropriate string attached to the
ends. This isn't working out too well though as there's too much
friction in the system, plus I designed it on the fly without actually
planning anything out.

What I did today was actually purchase that device at the link above.
If you look at the picture, it uses a geared sprocket with geared rails
for each axis for smooth manual motion as the sprocket is turned. I'm
wondering if I could mount a small motor alongside of each sprocket,
couple over the motor and sprocket with a rubber band to act as a belt
and move each axis by powering the motor. When I converted a small
telescope I have from manual to electric focus, that's exactly what was
done.... small motor alongside the manual focus and a belt placed over
the motor and focuser.

I'm not sure though what speed or type of motor I would need. A motor
like on the telescope would be ideal, but I don't have the specs for it.
Appreciate any ideas here.

Bill

 

[[email protected]]

Thanks to all for the responses so far.  You certainly have given me
plenty of ideas.  To give you an idea of what I have now, take a look at
this:

http://goo.gl/N1Qqq

I don't have this.  I fashioned something out of wood and used drawer
sliders, cut way down, for each slid-able axis.  If I want to move in
either x-x or y-y, I just pull the appropriate string attached to the
ends.  This isn't working out too well though as there's too much
friction in the system, plus I designed it on the fly without actually
planning anything out.

What I did today was actually purchase that device at the link above.
If you look at the picture, it uses a geared sprocket with geared rails
for each axis for smooth manual motion as the sprocket is turned.  I'm
wondering if I could mount a small motor alongside of each sprocket,
couple over the motor and sprocket with a rubber band to act as a belt
and move each axis by powering the motor.  When I converted a small
telescope I have from manual to electric focus, that's exactly what was
done.... small motor alongside the manual focus and a belt placed over
the motor and focuser.

I'm not sure though what speed or type of motor I would need.  A motor
like on the telescope would be ideal, but I don't have the specs for it.
  Appreciate any ideas here.

Bill

something like this? https://www.sparkfun.com/products/8912


-Lasse

 

[[email protected]]

Take a look at Marlin P. Jones & Assoc Inc., www.mpja.com. They have a
selection of steppers & dc motors & geared dc motors. The latter range
down to 12v/6.8 rpm.

Hul

Thanks to all for the responses so far. You certainly have given me
plenty of ideas. To give you an idea of what I have now, take a look at
this:

I don't have this. I fashioned something out of wood and used drawer
sliders, cut way down, for each slid-able axis. If I want to move in
either x-x or y-y, I just pull the appropriate string attached to the
ends. This isn't working out too well though as there's too much
friction in the system, plus I designed it on the fly without actually
planning anything out.

 

[George Herold]

Thanks to all for the responses so far.  You certainly have given me
plenty of ideas.  To give you an idea of what I have now, take a look at
this:

http://goo.gl/N1Qqq

I don't have this.  I fashioned something out of wood and used drawer
sliders, cut way down, for each slid-able axis.  If I want to move in
either x-x or y-y, I just pull the appropriate string attached to the
ends.  This isn't working out too well though as there's too much
friction in the system, plus I designed it on the fly without actually
planning anything out.

What I did today was actually purchase that device at the link above.
If you look at the picture, it uses a geared sprocket with geared rails
for each axis for smooth manual motion as the sprocket is turned.  I'm
wondering if I could mount a small motor alongside of each sprocket,
couple over the motor and sprocket with a rubber band to act as a belt
and move each axis by powering the motor.  When I converted a small
telescope I have from manual to electric focus, that's exactly what was
done.... small motor alongside the manual focus and a belt placed over
the motor and focuser.

I'm not sure though what speed or type of motor I would need.  A motor
like on the telescope would be ideal, but I don't have the specs for it.
  Appreciate any ideas here.

Bill







- Show quoted text -

I'm guessing you want a fairly low speed output. We get 1 RPM timing
motors from
Herbach and Rademan

http://www.herbach.com/

But I don't think they reverse.
Can you measure how much torque you need? That will help in picking a
motor.

George H.

 

[josephkk]

I have a small platform that has a pocket videocamera attached to it.
Since I have the camera and platform in a remote location, I need to be
able to move the camera slightly in two dirctions: toward and away from
an external lens (the lens is not attached and focus is done by moving
the camera toward or away from the lens) and also slightly in
perpendicular directions to and fro (because some objects are not
centered in the lens and the camera can move slightly to compensate).

I first tried making two small stacked platforms on top of modified
drawer sliders with strings attached. The idea was to pull a string to
move the camera in either of the directions above, but there is too much
stress needed to get the camera to move and I must find a better way.

Then the idea has occurred to attach a nut to the bottom of each
platform and then use a threaded rod with a motor attached to the rod to
move the platform in either direction. Since the camera needs to be
able to move slowly in any of the directions and go forward and reverse,
I'm not sure what type of motor would be suitable. I have some 3 Volt
DC hobby motors, but I think these are way too fast for the job plus I
doubt they reverse direction with polarity change. Can someone suggest
a suitable motor, preferably something surplus? BTW, the threaded rod
wouldn't need to be anything larger than 1/4" diameter or so.

Thanks,
Bill

I recommend you start from an inexpensive plastic X-Y stage. Then add a
couple of stepper motors with appropriate reduction drives. You may be
able to find all of this surplus (a better X-Y stage will be a big plus).

?-)