Basic Schematic

Note: Refer to the pin numbers on the inside of the Arduino component outline (i.e. D1, D2, A0, A1, etc.) and not the numbers on the outside of it (1, 2, 3...).

Inputs

Azimuth V - Analog voltage from rotator or rotator control unit, proportional to azimuth heading, 0 to 5 volts
Elevation V - Analog voltage from rotator or rotator control unit, proportional to elevation, 0 to 5 volts

Outputs

Rotate CCW - Pulled low to activate counter-clockwise (left) azimuthal rotation
Rotate CW - Pulled low to activate clockwise (right) azimuthal rotation
Rotate Down - Pulled low to activate downward elevation rotation
Rotate Up - Pulled low to activate upward elevation rotation
Speed Voltage - Analog voltage from 0 to 5 volts; 5 volts = maximum speed

The schematic above shows a basic setup supporting a 4 bit interface LCD, azimuth and elevation voltage (FEATURE_AZ_POSITION_POTENTIOMETER and FEATURE_EL_POSITION_POTENTIOMETER) inputs, manual buttons, and a single variable speed voltage output. Additional controls and options such as an azimuth present potentiometer, azimuth and elevation preset rotary encoders, and brake control lines can be added as needed if the appropriate pins are chosen and set in code at compilation time. If using with an azimuth-only rotator, all components related to elevation can be omitted. So, again, keep in mind the above schematic is a very basic unit that will work for most applications and additional features will require additional components.

The buttons and LCD be omitted if a simple computer to rotator interface is desired. If variable speed is not needed, the components associated with the Speed Voltage output (C7, R8) can be omitted.

If more sophisticated position sensors are desired, they can be connected to the Arduino pines based on settings within rotator_pins.h. I2C devices are merely connected to the I2C pins of the Arduino. The exact pins vary between Arduino models, and additional information is in the Arduino Wire reference.

Additional Schematic Diagrams

RemoteQTH.com offers a KiCad schematic of their hardware that you can use for additional guidance or hardware ideas.