Hey everyone, finally finished my automatic drive for the Celestron Skyris Filter Wheel!
This is fully USB powered and doesn't require an external power supply. I made this in order to save some money on automated filter wheels. I feel that an affordable solution was needed considering some automated filter wheels are selling for $300 or more...All it is is a stepper motor, a controller, and some software.
Skyris Filter wheel - $89.99
Gears - $1.40
Stepper Motor - $2.00
Stepper driver - $2.00
Arduino Nano - $3.20
My time - Negligible and unimportant
That's a much better price. Hopefully some of you can get some use out of this!
How it's constructed:
The center spindle is a press-fit solution. It's a little larger than what you'd probably want and will need a minor sanding down to press outwards and keep tension. This part is the most important as this is what allows your wheel to spin. The motor in this solution isn't very powerful, so we want to keep things as smooth as possible. If you don't use SketchUp and need something smaller, larger, shorter, longer, please let me know. I'm lucky enough to have a metal lathe here and I lathed the center spindle out of aluminum, but I know most people here won't have that solution so I made the spindle. Continuing off that, there are two springs and two steel balls that keep the filter wheel aligned during manual movement. I wanted to keep these incorporated but the motor is not strong enough with the (very limited) gear solution. These will have to be left out. The stepper motor is accurate enough to compensate for this however. If you need to you can also edit the programming into the Arduino to compensate / calibrate your steps like I did.
The electronics are all used from user pipshag's design. Please go to his page and throw him a follow or like as my programming is complete garbage and his electronic configuration saved me a lot of time and hassle!
This is a small case, as small as I could make it actually. There is no room for pin headers on the arduino, stepper driver, or stepper motor. Keep in mind when you purchase the products to make this that you make sure the pins come unsoldered. My stepper driver had pins on it by default, had to do some desoldering to directly attach wires.
You'll notice there are slots in the case, right in the middle that presses directly against the filter wheel. These are for the Hall sensor. I had trouble mounting the hall sensor inside the body and had to resort to the magnet and hall sensor facing a non-optimal direction. It works, but make sure you use a strong neodymium magnet that will penetrate the case of the filter wheel. If you don't feel like modifying your original filter wheel, you can use the link below in the Credit's section to download a copy of the filter's side wall. This will allow you to modify it without tearing into any of the original hardware.
I'll admit it, my programming is garbage. I've found tutorials on creating an ASCOM driver for this thing and I can't get it to compile. If someone has programming experience and wants to write up an ASCOM driver so this can be used with many different software titles, please do. For now with the way it is, you can use a serial communication program (ex. PuTTY) to send the commands manually.
4x M2 by at least 6mm length
3x M3 by at least 8mm length
2x M3 by at least 18mm length
2x M3 nylon lock nuts
2x M4 by at least 8mm length
2x M4 nuts
2x M4 lock washers
2x M4 Nylon locking nuts
1x 2GT 90-Tooth belt by 6mm width and 2mm pitch
2x GT2 16-tooth by 6mm wide by 8mm bore gears
Give credit where credit is due!