DMX Stepper motor controller

[dmxlights]

Hi,

I am hopping someone on here can help me I am looking for a ready made board that can control a stepper motor via DMX. I am looking for it to drive a camera slider over and back 2 meter at different speeds for the hole lengh of the slider and also I would like to be able to stop it any where on the slider.

 

 

 

[timmeh2]

Hi

 

For things like cameras lenses and movememt over that distance just a stepper on its own won't be enough. You'd need position feedback too. You could use the mechanical stop method like so many moving light manufacturers use but this tends to be light stuff like colour and gobo wheels. Pan and Tilt drives nearly always have a variety of optical sensors and microswitches for the end stops.

 

Have you considered linear actuators?

 

All the best

Timmeh

[dmxlights]

Hi Timmeh,

I have been thinking of having a microswitch at both ends so I would have some way telling it when it gets to the end. I have considered linear actuators but I may not have much space for it. The one I was thinking of is the one with a threded bar running the full lenth of the slider but I may not have space any bar thicker than 6-8mm

 

[theatretechie]

Have a look at these. http://www.bpesolutions.com/dmxproduct.html

 

Very similar to Milford Instruments which closed in the UK last year.

[dmxlights]

I have looked at their site and all the boards they do are about 3 time the price of Milford Instruments. I know the person who own Milford via a good friend and have got some custom made boards from them in the pass and at a good price.

 

I may also ues a DC motor with a gearbox and use it as it would make things a bit easyer to do

 

[musht]

HD winch servo or adapt a standard servo to continuous rotation

 

8 servo outs 45 quid https://robot-electronics.co.uk/DMX-usb-rx-d8.html

 

Trapezodial lead screw

 

https://www.ebay.co.uk/itm/Trapezoidal-Lead-Screw-10x2-Steel-NEW-1000mm-or-2000mm-ACME-10-x-2-UK-SELLER/183514330655

 

Much thinner and it will bind from flexing unspported.

 

Or toothed belt and pulleys, keeping it tensioned an issue.

[pmiller056]

Probably a bit too hefty for this application, but a satellite dish positioner. The linear types have a DC motor with a reduction gearbox, home switch and an encoder for feedback. Limit switches built in. Motion is slow, but very repeatable. Ones intended for larger dishes are designed for many 10's kg loading, pushing or pulling.

[dmxlights]

Thank you all for your replys so far and I am taking all the ideas and looking at them.

 

@ pmiller056 I did not think of a satellite positioner but as you said its to hefty.

I have also been been thinking of using a DC motor as I can use a DMX board that as PWM to drive the speed of the motor and I can also wire in micro switches at both ends with a relay to do revers. It could mean a DMX board with 2 channels all is needed. even 2 channels of PWM would work.

 

I am hopping to some test runs this weekend as I have DC motors and gearboxes. I may also have a board that has PWM that I have bought from Milford insturments a few years ago. Will post back here if I make any progress

 

[dmxlights]

I would like to thank every oen who replyed and give me ideas for this. I have gone with a DC motor with a gearbox and I have also made a box that I can connect to this which will allow me also to use it without DMX which one thing I did not think of. I have one box with a DMX board in it which allows me to set the speed of the slide across the rails and also stops when it get to the end. I can also stop it anywhere I like and also go in the opsite direction as well.

I am waitting on a dc PWM motor speed control board to come so I can finish the box that I can use when I don't have DMX near by or when out using in the feld