Arduino Moonlite Focuser
This project was originally built several years ago using an Adafruit V1 motor controller with an Arduino UNO that was programmed with the e. j. holmes Arduino Focuser sketch. But I can't find an INDI driver for it, so I reprogrammed the Arduino with the Orly (andico.org) focuser sketch that's written for the same hardware but uses the Moonlite protocol, which does have an INDI driver.
Compiling and uploading the new sketch in the Arduino IDE went without error and the MoonliteDRO driver is now controlling the focuser.
The only changes I had to make to the hardware were moving the stepper motor wiring from the M3/M4 terminals to M1/M2 on the AdaFruit board, and I added a heatsink to the associated L293 driver IC as recommended on the andico.org page.
The only changes I had to make to the hardware were moving the stepper motor wiring from the M3/M4 terminals to M1/M2 on the AdaFruit board, and I added a heatsink to the associated L293 driver IC as recommended on the andico.org page.
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The Arduino and Adafruit motor controller combo is housed in a Radio Shack project box. It is connected from the motor controller to the motor with a 4-conductor cable which plugs into an RJ-11 connector on the motor.
I mounted a coaxial power connector on the project box and connected it to the external power input of the Adafruit motor controller so I can connect an external power supply. The only modification to the Adafruit board was moving its power LED to the box lid. |
Moonlite focuser adapter
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The stepper motor and shaft adapter installed on my Moonlite focuser. The mounting bracket for the motor is cut from a 4" piece of right-angle aluminum stock. It is attached to the Moonlite focuser with one brass screw. I now have a 3-D printer so I plan to print a custom mounting bracket one of these days.
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Closeup of the shaft adapter and clutch. It is basically three pieces: (1) the left side motor adapter, (2) the center shaft lock, and (3) the right side Moonlite adapter.
(1) The motor (left) side portion of the shaft adapter is a short piece of .625" aluminum rod with a 5mm center bore and set screw to secure the motor shaft. The right half of it has been turned down to 3/8" and threaded to 3/8-32. (2) The shaft lock mechanism is the same as used on my C-11 to lock the mirror supports and screws onto the 3/8-32 motor adapter threads. (3) The Moonlite (right) side of the adapter is also .625" diameter and has a 1/4" diameter shaft extending from the left side that inserts into the shaft lock mechanism. The right side slides into the Moonlite in place of the knob, and is turned down to 15mm in diameter and 10mm wide to match the knob that was removed. This side also has a 5mm bore to match the focuser shaft and is secured with another set screw. |
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To unlock the motor and manually focus the Moonlite just loosen the thumbnut.
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The focuser motor mounted to the moonlite. The motor was repurposed from an old EQ-3 kit I had years ago.
I placed a rubber washer between the mounting bracket and the Moonlite to keep from scratching the focuser's finish. The Moonlite already had a threaded 8x32 hole to attach the bracket. There's also a second rubber washer between the motor and mounting bracket on the screw securing the motor. |
Astro-Tech AT6RC Focuser Adapter
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To mount the stepper motor to the Astro-Tech Crayford I made a radius block that attaches to the bottom of the focuser using two existing screw holes. To this I attached a cross bar with a plate to hold the motor.
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I made a new focuser-side shaft adapter to mate the Astro-Tech focuser shaft with the existing motor adapter from the Moonlite setup.
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The new shaft adapter for the Astro-Tech replaces the adapter for the moonlite shaft. The other adapter parts are common to the Moonlite adapter.
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Page created 1/1/2021
Last updated 5/1/2023
Last updated 5/1/2023
