Quote:
Originally Posted by BeardFace
Hey all, I thought a fun ongoing project this year might be to setup a remote observatory, at my family's farm, and wanted to get some advice on the dome and automation system. Ideally I'm trying to keep it within a 12v range as I hope to power everything off of solar. So far my idea is:
Dome shape and construction
I'm thinking about basing the construction off of this, as it looks approachable and sturdy http://astro.neutral.org/fibreglass-...ope-dome.shtml
Dome control unit
For Dome Control I'm thinking Velleman K8055N loaded with LesvedomeNet
http://www.dppobservatory.net/DomeAu...DomeDriver.php
Motor
As for the motor I'm not sure what kind of strength is required, so I've been investigating 12vdc motors and I think these are the two strongest I've found:
https://www.robotshop.com/en/12v-17a...per-motor.html
or
https://www.phidgets.com/?tier=3&cat...=16&prodid=295
The stronger the better, as if it's decent enough I can actually get my brothers to weld up a steel frame for extra durability.
Driving mechanics
I was actually thinking of copying the NexDome approach and using a gear attached to the motor, combined with some flexible gear racks like this https://www.smallparts.com.au/store/...acksflexible/?
Azimuth sensor
Similar to the motor I'm thinking of attaching a gear on to an encoder, like this one https://www.plcdirect.eu/products/en...t/trd-nh4-rzwd
And I'll probably need a magnetic switch for the home position
Shutter
This part I'm not too sure of and I'd be keen to hear people's thoughts. I was thinking of using the design above but maybe a single shutter sliding across horizontally? Or are there specific advantages to having two shutters meet in the middle? As far as I can tell it'll also need a battery unit that can be charged from the home position of the azimuth. Then two magnetic switches for open and closed position?
Controlling everything
For the last bit I'm thinking of using a 12vdc mini computer, like the Qotom http://www.qotom.net/product/78.html to run Voyager. This would hook into the Velleman K8055N for Dome/Shutter control, control some relays to turn off the equipment when not in use, maybe run some ventilation etc as well. Then I'd access the system remotely with a 4G router that takes a SIM, and control through the Voyager web portal.
Solar power
This part I'm not as worried about, as there are plenty of options out there and it will be the last component to go in.
So yeah, I'd love to hear people's feedback on my proposed setup. What's missing, concerns, things I've got entirely wrong in my research? I realise it'd be easier to just buy a NexDome but I like the idea of having a project for the year, and I don't have that kind of cash! I'm a programmer by trade and also don't mind getting my hands dirty with construction and electronics. I'm also considering a ROR setup, but want to explore all the dome options first.
Cheers! |
Hello Nial
You are mixing the Levesdome hardware with a stepper motor, you need a DC motor - actually it is a servo motor, any DC motor can be made into a servo motor with an encoder added to it, I had a stepper setup like you describe and after 2 years I gave up on it and went the Levesdome route, was simple and it works!
The problem with steppers is that despite the communities best intents, every dome is different so the hardware / software is an issue, the Nexdome route was stuffed up by Nexdome as the paid a bloke in the UK to re-write the code, in doing so they removed the ability to change the step/pulley size/belt pitch and length, so it works really well on a Nexdome not so much on any other.
Here is a link to my build, I did a 3m ally dome, the photos show you my answers to your questions, the only change I would do now is I would make the dome out of ally but in a flat trapazoidal ( sp?? ) shape, no compound curves but still no leaks. The good thing with ally is if you have wood working tools you can do it.
https://1drv.ms/u/s!AhXA8zZYfT5YjT_5...1hOMp?e=I7qaas
Best regards
Ed