The Arduino Focuser

UPDATE: The Ardunio Focuser was just featured in the October issue of Astronomy Now magazine in the UK. Read about it on page 76-77!

In case you’ve never heard of it, the “Arduino is a tool for the design and development of embedded computer systems, consisting of a simple open hardware design for a single-board microcontroller, with embedded I/O support and a standard programming language.” In other words, it kicks ass.

This is where I decided to start my homemade ASCOM compliant computerized focuser. My goal was to use the Arduino to control a single stepper motor that in turn would be controlled by auto focusing software such as MaximDL or FocusMax using an ASCOM driver.

This is where I decided to start my homemade ASCOM compliant computerized focuser. My goal was to use the Arduino to control a single stepper motor that in turn would be controlled by auto focusing software such as MaximDL or FocusMax using an ASCOM driver.

The Hardware

The stepper motor I’m using is an old stepper I had from a single axis drive system for and EQ3 mount, which is a high resolution (geared) stepper motor. In order to control the stepper motor, I came across a motor shield by Adafruit Industries. It also included a library for microstepping, which made it ideal for high precision focus control. The stepper motor is connected to the Arduino board via the motor shield through an RS232 cable.

The Software

The software can be found at https://github.com/ejholmes/Arduino-Focuser. The code is licensed under the GPL V2, so feel free to use it freely, but please mention my initial project!

The Final Product

It supports absolute positioning of the focuser up to around 13,000 points (on my focuser) of focus.