Arduino code driving a rotation mechanism for telescope aperture masks. All code in this repository except for the TimerOne library was written by Ed Foley.

• Arduino Uno
• Arduino Motor Shield
• SparkFun Electronics stepper motor ROB-09238
• SunFounder Hall switch TS0215
• Compatible USB cable
• Compatible power supply
• Aperture mask rotation mechanism assembly (see Ed Foley's thesis, A Rotating Aperture Mask for Small Telescopes, published 2019)

• Arduino IDE

1. Clone this repository.
2. Set the Arduino sketchbook location to the new MaskRotator directory.
3. Open mask_rotator.ino using the Arduino IDE.
4. Connect the power supply to the Arduino Uno.
5. Connect the computer to the Arduino Uno with a USB cable.
6. Press Ctrl+U to upload the sketch.

Either

• Open the serial monitor with Ctrl+Shift+M and type commands manually (e.g. rt18000 to spin the mask 180 degrees), or
• Execute a custom program that implements the rotator's communication protocol.

See A Rotating Aperture Mask for Small Telescopes for complete information about the communications protocol, or inspect the source of mask_rotator.ino.