For the record, I did do a search in an attempt to find an answer before posing the question...
I have been tasked with building a mini theatre enclosure to be used for multiple subjects (including puppets) at our local lodge. Because of my background in custom cabinetry/mixed medium sculpting I believe I can handle the construction of the 'theatre' itself, but after having stumbled across the potential abilities of Arduino, I am wanting to use it to open and close the theatre's stage curtains which would require Arduino interacting with small motors of some type for the physical opening and closing, plus stopping the motors at their maximum open position and their maximum closed position. Controlling this via some sort of remote control as well.
I'm hoping someone will be kind enough to point me in the correct direction, and/or give me a bump start on my way to Arduino enlightenment
I genuinely apologize if I am asking a rather SIMPLE question for the membership, or, perhaps asked it in the wrong form or forum. If I have indeed performed such a 'faux pas', please be so kind as to let me know and I will try to do better next time.
First take a look here to see how it's done in a real theatre. Then you need to think how to scale that down. I would suggest you use a drum for moving the cord with a small motor and gearbox such as this one which is from Hong Kong. That stepper motor has a built-in gearbox and is intended for HVAC applications so should be up to the task. You will also need a pair of limit switches to detect when the curtains are fully open and fully closed. A small tab attached to one curtain header would do the job together with a couple of these switches. You could add a radio link for remote control but that might be a bit over the top and a couple of remote buttons would probably be appropriate.
Appreciate the helping hand pard', and the links...great help.
I was indeed thinking about utilizing a small drum for pay out/retrieve duties for the cable, similar to what you might see (in the vertical position) in a standard torsion spring garage door setup so that's along the lines I was thinking as well. This 'theatre' is a fairly decent sized enclosure and the curtains, plus liners I was thinking about using are quite heavy (approx. 20lbs+) so I'm not entirely sure of the power of the stepper motor you provided a link to having enough Umnnff! I have queried the seller to get some clarity on that motors power availability.
The optical limit switches are a dandy solution to the curtain travel issues...definitely something I can play around with and (hopefully) figure out.
On the radio link being "over the top"...after seeing a voice command set up of another project here where the lights blinked differently, upon voice command well...my mind is now off on THAT very cool potential option!
Again, genuine thanks for taking the time help out an old, retired Marine with a new hobby. 8)
Any further input or help from anyone is greatly appreciated...perhaps there's another similar project on the board that I missed that someone could point me at for inspiration?
If you have limit switches - which are probably essential - you probably don't need a stepper motor for a job like this. Any suitable DC motor should do as long as you have a suitable interface (H-bridge in the jargon) that can handle the motor current and take instructions from the Arduino. You will also need an interface board for the stepper motor and the DC motor will be much easier to program - set direction, switch on, wait for the limit switch, switch off.
A cheap source of high torque low speed motors might be a used car windscreen wiper motor. A regular DC motor will need to be geared down to reduce speed and increase torque. You can get powerful DC motors for a few £/$ but then you will need to get or build a suitable gear box. A worm reduction gear will give a large reduction ratio. You can also buy DC motors with gearboxes incorporated.
It would be useful if you could make an estimate of the force needed to move the curtains reliably - perhaps with a mock-up full sized model.
Ah, I was thinking small puppets whereas yours are obviously larger. As Robin2 has said 20lb of curtains will probably require a much more powerful motor or a larger ratio gearbox. A DC motor & gearbox will certainly do the job of opening and closing the curtains and will be easier to implement but, in some circumstances, you may want to stop somewhere in between. A timed period of running any motor would allow this but using a stepper motor would mean that you could program exact stopping points in steps. The choice is yours.
Good luck with it from a retired broadcast TV engineer and theatre technician!
