8 DMX Servomotors

Servomotor = position-controlled motor.

DMX Servomotor Board

Servomotors are used to animate objects, sculpture elements, parts of robots, or covers in front of projectors...
These motors rotate or position objects of varying weights (up to several kilograms for the more powerful ones) to a precise location.

The most common ones allow positioning over a quarter or half turn, some rotate continuously at variable speeds, and others are multi-turn winch servos. The variety of heads that can be adapted and fixed to the motor makes it possible to attach any object to be moved.

Servo Control Board with DMX Protocol.
8 Servos DMX Board: configuration, outputs, power supply.

The Interface-Z Servomotor board allows you to control 8 of these motors simply by sending them real-time position commands. It recognizes the commands in the standard DMX protocol, used in stage control rooms, lighting consoles, motorized projectors, and light dimmers. The board ensures each object stays in the chosen position until the next movement, regardless of its weight.

These positions are distributed over the chosen range: 90° or 120° (or even 180°, depending on the connected motor). This board also allows you to save rest positions and has a Safety mode.

Servomotors can be purchased at any hobby store, but we can also supply them. The board’s documentation shows how to connect them, regardless of their brand. The most common servomotors are fully controllable with this board. Our Servo Control boards are compatible with all types of standard motors: mini-servos, metal gearboxes, winches, continuous rotation, etc. The only thing to check is the wiring order, which is mostly compatible with our boards, but variations may exist.

For more details on servomotors, refer to the "Servomotor" page in the Tips section.

Examples of applications

Objects fixed on servomotors can be:

- tools: sensors (rangefinders, cameras, optical systems, cameras, etc.) or control buttons (adjustment potentiometers for devices, adjustment sliders);
- or elements of sculptures or decor, contributing to the visual effect perceived by the public in the installation.

Example of Interface-Z servomotor applied to a cat game.

Illustration

By attaching wooden sticks to the rotating head of servomotors, it is possible to create puppet animations, where the movements could be linked to music, public behavior, or even atmospheric conditions.

By using modeling winches, you can tension cables to move fabrics, raise and lower objects.

They are also used to close off, completely or partially with perforated plates, light projectors or a video projector (which allows achieving absolute black, difficult with just the video projector).
Very mechanically, they are often used to simply replace a finger... This is a way to automate pressing buttons on a device that cannot be disassembled, or the movement of a lighting or sound control slider.

It is also possible to couple two servomotors to orient an object in three spatial directions, for example, to make a small projector with ultraluminous LEDs.

It is important to carefully size the servomotors based on the weight they lift: a motor that is too weak will strain and could break.

Sizing a servomotor relative to the weight to be moved.
On the left, an under-sized motor, struggling and forcing;
on the right, a motor sufficiently powerful for this application.

Power supply, rest position, safety mode, interference... Some things to know.

Tips and tricks

• The board is compatible with standards switching power supplies for PCs, which is the simplest solution in the case of an installation with 220 V power. These power supplies provide 5 Volts for the motors and 12 Volts for the board. The servomotor board documentation explains how to use this type of power supply.

This short video shows the use and available wires on this type of power supply.

• The system can run with a 9V battery for the board and a modeling battery pack for the servomotors, in the case of a mobile use (e.g., walking robot).
• The memorization of rest positions allows control over the motors' position when the board is connected but not receiving commands.
• The safety mode prevents motor overloading in the case of programming failure (provided that comfortable rest positions for the setup have been defined).
• Be cautious with long extensions: servomotors usually have very short connection wires, which are directly plugged into the board. If the servomotor needs to be moved away from the board, it’s not enough to simply plug it into a 3-wire extension as you would for sensors. The servomotor may stutter, tremble, and fail to respond properly to commands. The solution is to insert a small noise filter between the servomotor and the extension. If the distance between the board and the servo exceeds 3 meters, it’s better if the extension itself is shielded.

Technical considerations

How to connect servomotors to the board, which power supply to use, which software is compatible with the board?

Connections, control, power supply, etc.

Compatibility and control

The 8 Servomotors DMX electronic board can be controlled from any software or console/mixer/controller capable of sending DMX messages.

Connectors and mounting

• DMX input: male and female 3-pin XLR connectors;
• 8 standard connectors for servomotors, 3-pin header;
• 4-point screw terminal for low-voltage power supplies;
• 4 mounting holes, at the corners.

Connecting the servomotors

Make sure to connect the wires in the correct direction to avoid damaging the motor. A marking on the board helps with orientation.

Technical specifications

8 Servomotor DMX Interface-Z board.
Power supply, DMX connectors, servomotors.

Power supply

• Power supply for the board: 9 V to 15 V DC, capable of providing 100 mA
• Power supply for servomotors: 4.5 V to 6 V DC, capable of providing 8 A

See Tips & Tricks for using a PC power supply with this board.

To improve the product's quality, we deliberately separated the two types of power supplies to avoid interference from the servomotors, which would otherwise cause uncontrollable vibrations in the case of intense motor load.

Servomotor adjustment

- Standard servomotor range adjustable to 90° or 120°, in 128 steps or 3500 steps.

Controlling the servomotors

- By DMX commands.
- The entire 512 DMX channels are addressable.

Safety mode and rest position memorization

- Activated by switches on the board.
- Be cautious not to activate the memorization if you don't wish to use it.

Memorizing positions allows the servomotors to automatically return to these chosen positions the next time the board starts up.

The safety feature ensures that, in the absence of MIDI commands, the servomotors return to the rest position. For example, if the computer controlling the motors stops unexpectedly, this prevents overloading and damage.

Be cautious with running status in MIDI.

Documentation and resources

Documentation:

• 8-Servo-DMX-Interface-Z board documentation.pdf
• Servomotor information page.

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