Re: [Cameramakers] Stepping motors / was making a panoramic camera
I know from my own experimenting with stepper motors that if they are not loaded up properly they will not run properly. They need a load to dampen their motion. There are good tutorials on stepper on the web. At work I have seen smaller and smaller steppers with reduction gear units and all. There are small stepper motors with drivers attached like http://www.imshome.com/Product%20Datasheets/MDrive14_datasheet.pdf A good source of info can be found at http://www.motioncontrol.com/ --Greg Nuspel "Nothing is so embarassing as watching someone do something that you said couldn't be done." Sam Ewing ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Stepping motors / was making a panoramic camera
Please look at the old floppy drives. The motors are typically almost cubes 40 to 50 mm on a side. (There are exceptions of various kinds so try again if the first one you look at is not suitable.) I have a few nice steppers which are flat disks less than 20 mm thick, if my memory is failing me, but maybe 60 or a bit more in diameter. However, these have lots of steps (400 to 500) and need only two phases to drive them. (I would offer you one except the postage is terrible from here!) Unfortunately, many 500 step motors are 5 phase models; good stuff but not convenient for this application. The steppers in 3.5 inch floppies are tiny but I would not bet on their ability to drive what you have in mind at the speed you want so I would avoid them unless you are quite adventurous! How fast does one of these cameras complete a sweep? Besides steppers, normal motors run at pretty constant speed if the load stays constant. You must just keep the voltage constant. There are some tiny motors with gears in dead CD drives. The voltages are low so battery power is little problem. Bob At 22:49 26.09.02 +0200, you wrote: >Thanks Bob and Huw . > >Well I know a little about electronics, they were part of my studies >but it's a bit far away now :o) >I got a few step motors but from old printers they are really huge >ones and from the scanner that broke up it's a 7.5 degrees I can >gear it with all the pulley and belt I collected from various things >but well in fact I've got to test different solutions because I >do not want a 20 pounds camera (without the battery ) ! :o) > >( Well after that I'll have to do a led enlarger for panoramic shots >!! ;o) ) > >Cedric > >On Wed, 25 Sep 2002 22:51:47 +0100, Huw Finney wrote: > >Hi, > >Stepper motors can be geared and it works very well, take a look > >inside > >a printer (to be found in your local skip (dumpster)) there is > >usualy a > >couple of big steppers and some gears and a very useful toothed >belt. > >There are plenty of stepper driver chips out there. If you get > >stuck on > >the electronics I can sketch something for you. > > > >Huw (of LED enlarger fame) > > > > > > > >___ > >Cameramakers mailing list > >[EMAIL PROTECTED] > >http://rmp.opusis.com/mailman/listinfo/cameramakers > > >-- >Cedric Malitte, [EMAIL PROTECTED] on 26/09/2002 > > > > >___ >Cameramakers mailing list >[EMAIL PROTECTED] >http://rmp.opusis.com/mailman/listinfo/cameramakers ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Stepping motors / was making a panoramic camera
It would not be hard to do without a microprocessor, but it is almost surely easier when one is used (very few components but some programming instead. The pure hardware method would require a fair number of components, though by resorting to position sensitive switches to sense the end of travel, the job might still be quite simple. At one end you would just reverse the counting sequence to rotate back to the starting place. (closing the shutter at the same time, probably mechanically.) Bob At 10:53 26.09.02 -0700, you wrote: >--- Huw Finney <[EMAIL PROTECTED]> wrote: > > Hi, > > Stepper motors can be geared and it works very well, > > take a look inside >...snip... >stepper motors, hm? I'm going to try and find a >non-battery method first (just the romantic in me... >plus I'm all thumbs about electronics). Can you have >a self-contained stepper motor controller for >something like this (turn 180 one way; turn 180 the >other way) without some sort of >microcontroller/pic/basic stamp? > >thanks, > >-- P > >__ >Do You Yahoo!? >Yahoo! Autos - Get free new car price quotes >http://autos.yahoo.com >___ >Cameramakers mailing list >[EMAIL PROTECTED] >http://rmp.opusis.com/mailman/listinfo/cameramakers ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Stepping motors / was making a panoramic camera
Thanks Bob and Huw . Well I know a little about electronics, they were part of my studies but it's a bit far away now :o) I got a few step motors but from old printers they are really huge ones and from the scanner that broke up it's a 7.5 degrees I can gear it with all the pulley and belt I collected from various things but well in fact I've got to test different solutions because I do not want a 20 pounds camera (without the battery ) ! :o) ( Well after that I'll have to do a led enlarger for panoramic shots !! ;o) ) Cedric On Wed, 25 Sep 2002 22:51:47 +0100, Huw Finney wrote: >Hi, >Stepper motors can be geared and it works very well, take a look >inside >a printer (to be found in your local skip (dumpster)) there is >usualy a >couple of big steppers and some gears and a very useful toothed belt. >There are plenty of stepper driver chips out there. If you get >stuck on >the electronics I can sketch something for you. > >Huw (of LED enlarger fame) > > > >___ >Cameramakers mailing list >[EMAIL PROTECTED] >http://rmp.opusis.com/mailman/listinfo/cameramakers -- Cedric Malitte, [EMAIL PROTECTED] on 26/09/2002 ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Stepping motors / was making a panoramic camera
--- Huw Finney <[EMAIL PROTECTED]> wrote: > Hi, > Stepper motors can be geared and it works very well, > take a look inside ...snip... stepper motors, hm? I'm going to try and find a non-battery method first (just the romantic in me... plus I'm all thumbs about electronics). Can you have a self-contained stepper motor controller for something like this (turn 180 one way; turn 180 the other way) without some sort of microcontroller/pic/basic stamp? thanks, -- P __ Do You Yahoo!? Yahoo! Autos - Get free new car price quotes http://autos.yahoo.com ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
[Cameramakers] Stepping motors / was making a panoramic camera
Hi, Stepper motors can be geared and it works very well, take a look inside a printer (to be found in your local skip (dumpster)) there is usualy a couple of big steppers and some gears and a very useful toothed belt. There are plenty of stepper driver chips out there. If you get stuck on the electronics I can sketch something for you. Huw (of LED enlarger fame) ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Stepping motors / was making a panoramic camera
Usually you will not experience great difficulty in trying to reach 500 to 1000 steps per second with decent stepping motors. Better ones will be fine at double that rate. You can reach 10,000 steps per second with more refined circuits but that may not be worth your effort. 200 step per revolution (1.8 degrees) motors ought to be relatively cheap and a solution as simple as half steps will double that. Driving with the correct amplitude sine waves effectively raises the number of steps by a considerable factor (so-called "microstep" service) Your main desire is smoothness of motion so computer control is not needed (although it might make sense with modern, cheap processors which are easy to program). Analog circuits will easily make the two-phase drive signal and sine waves will produce rather smooth motion, probably better than what you will get with clockwork devices. Certainly I would expect better constancy of the speed of the sweep over the length of the film, i.e., more uniform exposure. You can find respectable motors in printers and old floppy drives (5.25 inch!) which other folks are throwing away. There is no need to pay much (if anything except patience). Plotters are also obsolete and can have good motors (I have one with 400 to 500 hundred steps per turn). You can feel the step rate after some experience and at least quickly eliminate the 7.5 degree types. Some printers and plotters might also offer you step down gearing already attached. Bob At 00:04 26.09.02 +0200, you wrote: >I thought about taking motors with steps as little as 1.5 degrees or >half but they are very expensive + I do not know if such a motor >could be strong enough to drive the camera with a low ratio gear box >and light weight... >I am still stuck with the max steps/s. I really have to take down >each motor specs and calculate the gear for best torque/speed ratio. >It's tricky :o) ! > >Sometimes I think I'm real nut trying to realize my dream ! > >Cedric >On Tue, 24 Sep 2002 23:25:47 +0200, Robert Mueller wrote: > >If you drive stepping motors with a pair of 90 degrees out of phase > >sine > >waves (sine plus cosine) you will often find the motion to be much > >smoother (I assume you would have 2 phase motors). I suggest > >selecting > >motors with finer steps, 200 per revolution or more. I have seen > >400 to > >500 step, two phase motors in applications like plotters but you > >will need > >some luck or patience to find these; however, 200 ought to be good > >enough. > > > >Bob > > > > > > > > >___ >Cameramakers mailing list >[EMAIL PROTECTED] >http://rmp.opusis.com/mailman/listinfo/cameramakers ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
[Cameramakers] Stepping motors / was making a panoramic camera
I thought about taking motors with steps as little as 1.5 degrees or half but they are very expensive + I do not know if such a motor could be strong enough to drive the camera with a low ratio gear box and light weight... I am still stuck with the max steps/s. I really have to take down each motor specs and calculate the gear for best torque/speed ratio. It's tricky :o) ! Sometimes I think I'm real nut trying to realize my dream ! Cedric On Tue, 24 Sep 2002 23:25:47 +0200, Robert Mueller wrote: >If you drive stepping motors with a pair of 90 degrees out of phase >sine >waves (sine plus cosine) you will often find the motion to be much >smoother (I assume you would have 2 phase motors). I suggest >selecting >motors with finer steps, 200 per revolution or more. I have seen >400 to >500 step, two phase motors in applications like plotters but you >will need >some luck or patience to find these; however, 200 ought to be good >enough. > >Bob > > ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
