Skip to content

Actuators - to make stuff happen

Actuators are devices that you can add to make things happen under the control of the Command station. For example throwing a turnout, setting a signal or switching lights. There are basically two types of actuator that will commonly be used:

  • PWM output used for Servo movement of turnouts, semaphore signals, crossing gates, fancy animations and LED fading.
  • Digital output (On/Off) mostly used for LEDs, relays and some turnout types.

Other actuator types include:

  • NeoPixel output used for advanced lighting, mimic panels, signals etc.
  • Sound players
  • Turntable control systems

Servo actuators

Servo actuators generally use a PCA9685 device which can connect up to 16 Servos or LEDs over a single I2C connection. This device also acts to provide servo movement power separately from the movement control signal.

EXRAIL is used to

  • Define the PCA9685 connection and its address so that each output can be given a unique VPIN to control it.
  • For turnouts define a SERVO_TURNOUT for each VPIN so that the rest of DCC-EX can throw or close this turnout without knowledge of the underlying mechanism.
  • For semaphore signals, define a SERVO_SIGNAL to that the rest of DCC-EX can control the signal.
  • Control animation servos directly, such as crossing gates or shed doors.

Digital actuators

Digital outputs are generally connected via an MCP23017 device which offers up to 16 output pins on a single I2C connection.

EXRAIL is used to

  • Define the MCP23017 connection and its address so that each output can be given a unique VPIN to control it.
  • Set or reset the pin output when appropriate