How to Control a Servo with DMX

Control of a servo with DMX is now very possible because of available microchips and controllers. DMX is the lighting industry standard. It allows up to 512 different channels of data passing through simple wiring to control anything capable of receiving DMX input. The servos can be used to move animatronics, museum pieces, robotics, and anything that requires precision control. This article will help you get started with control of a servo using the DMX protocol.

Instructions

1. 

   Find a controller capable of operating a servo motor using DMX data input. There are several different controllers available ranging in quality from hobby to professional. Some companies offering DMX servo controllers are Gilderfluke, Blue Point Engineering, Northlight, and Skulltonix. The price range of these controllers are $49 (Northlight) to $336 (Gilderfluke). Controller boards typically control between 8 to 16 servos.

2. Get a source of DMX capable of sending the input data needed to control servo motors. There are many different sources of DMX, but you must take in account the language of the controller you are using. The controllers have a microchip that is looking for a specific set of instructions so understand this before selecting a DMX source.

   On a DMX network, think of the DMX source as the master. All the other components on the systems act as slaves doing things that are instructed by the DMX source. Some good choices may be the ENTEC open DMX, ENTEC pro, Brookshire software RAPU, Gilderfluke BR-Smartmedia, or even a simple DMX lighting board.

3. Get DMX animation software to control the movements of the servos. You can either write your own program, which some top studios have done, or use software designed to control servos. There is some example code on the Northlight website. Otherwise consider using Gilderfluke's free PC-MACs animation control software or VSA from Brookshire software. Both these programs can control many different scenes and can sync movement to sound. Gilderfluke's software is much more robust, but you will have to use their equipment to use the software. VSA is more flexible on the type of equipment it works with, but you will have to do more troubleshooting on your own.

4. 

   Use twisted pair wire to send the DMX data from the DMX source to the DMX servo controller. Since the DMX protocol is based on RS-485 standards, the wire length of the network can be up to approximately 1 mile. This is a huge advantage over serial cable or LAN cable. Attach cable sections together with XLR connectors. You will either need to use a 5 pin XLR or 3 pin XLR depending on the type of DMX controller you are using. If you need to split DMX cabling, you will have to use a DMX splitter. There are serval manufacturer's of splitters like Doug Fleenor Design, Chauvet, or BPESolutions.

5. Provide a power source for the servo motors. In some cases, depending on the controller used, if a minimum amount of smaller servos are used, they may be able to be powered by the servo controller itself. If larger high torque servos or more than four smaller servos are used, performance and speed will be effected by powering from the servo controller, so a separate power supply should be provided for the servos.

Tips & Warnings

• Price all the component you will need your for entire DMX project before purchasing the first item.

Resources

• Chauvet Data Stream 4 DMX Splitter