Having recently started experimenting with the idea of DMX-controlled servos for grating and lumia effects, I decided to check out a modifed hobby servo available from a company called Parallax here in the U.S., which specializes in microcontrollers and related components for robotics and other electronics applications. One of the items they sell is a modified standard Futaba hobby servo, that has been adapted for continuous rotation operation.
They work great, and inexpensive, too!!
http://www.parallax.com/Store/Access...%2cProductName
Since I already have a Northlight DMX servo controller currently in use on my "Jolly Green Poly Slab" experiment, I decided to give one of the Parallax servos a "spin".
http://photonlexicon.com/forums/show...53&postcount=1),
(Note - Having just read Dave's post about the DMX servo controller they're offering at LaserShow Parts, I suspect their board may offer finer low-speed control. I might have to check that out...)
http://photonlexicon.com/forums/show...79&postcount=1
Anyway, using my existing DMX servo controller, the Parallax servo, and DMX capabilities of my Pangolin QM2000.net and the QM_DMX console applet, here's my results:
DMX setting of 146 = servo stopped. Solid. No jitter, no nothing!!
DMX settings of 147 to 255 = counterclockwise rotation, with servo speed increasing as DMX value increases.
DMX settings of 145 to 0 = clockwise rotation, with servo speed increasing as the DMX value decreases.
Slowest possible rotation settings are at DMX values 145 and 147. At these settings, the servo rotates at a consistent 3 1/4 RPM (I can live with that!! )
Fastest possible rotation settings are at DMX values of 0 and 255. At these settings, the servo rotates at a consistent 50 RPM.
So, there you go - cheap, reliable motors for lumia and grating effects wheels that require continuous, variable rotation! Adding a wheel to the servo is easy, too - a dab of silicon adhesive will easily attach just about any glass or plastic wheel or rod to the nylon output wheel of the servo! With a multi-channel DMX controller board, a couple of Parallax continuous rotation servos for the wheels, and a few standard servos to work the non-rotating optics, you could add quite an effects setup to the projector for very little investment!
I hope to test my "lumia wheel" with one of these later this evening.
In the interim, here's the required photo.
Look - it's a servo!! :