Topic: Feasibility Question
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Jun 08, 2012, 07:15 pm
Alright, I'm new to Arduino (by new I mean I haven't actually DONE anything yet with it), but understand the concepts and have just ordered an Arduino Uno kit to start playing around with. I have a few projects lingering in the back of my mind that I'd like to build up to, one of which I'm here to ask about.
Barn door tracker
For those not familiar with this item, it is for astrophotography. The earth is constantly rotating, therefore long exposures of the night sky show movement of stars. While this sometimes makes for a cool effect, other times it is desirable to have a clear shot of one celestial item. These barn door trackers move at the speed the earth rotates in order to eliminate these star trails. Some people have created versions that use a motor that turns at a fixed speed- this is a problem because it limits the amount of time your long exposures can be before it starts to be incorrect. This is due to using a straight drive bolt- a curved drive bolt would solve the issue, but these are hard to come by/make. The other problem is that the left most side of the platform (where the hinge is) must be pointed directly at the North Star. If you're off a little bit, you will get subpar results. It's fairly difficult to get it spot on.
My intended project is to mitigate both of these issues via Arduino. I would like to somehow input my location via GPS (possibly from my Android phone submitted via Bluetooth?) to determine my location on the globe, then use the date/time information to know at what point of the Earth's rotation around the sun we are in, a compass to signal which way the camera is facing, and some sort of level to determine how the platform is oriented. The microcontroller could then use all of these inputs to do some geometry/trigonometry to determine where the north star is, and send the approriate outputs to any of three separate motors that would orient the camera correctly.
The part about a straight vs curved drive bolt would be addressed by adjusting the speed at which the motor turns the drive bolt, depending upon the current angle of the barn door tracker (ie. it would slow down as it approaches 90 degrees).
So all you experienced Arduino'ers, my question is- Am I crazy? Or is this feasible? It's obviously quite a task and nothing I plan to dive directly into. There are many building blocks along the way I need to go through to develop the appropriate skillset, but I think I have the general mappings of the project laid out in my head. Are there any limitations I'm unaware of that jump right out at you that are current non-starters?
Location: Gosport, UK
Re: Feasibility Question
Jun 08, 2012, 07:25 pm
This was discussed quite recently - http://arduino.cc/forum/index.php/topic,106404.0.html
Re: Feasibility Question
Jun 08, 2012, 08:19 pm
That post refers to the second part of the project, yes. And that part I'm not so worried about. I'm more worried about hitting a roadblock that, given my current knowledge of Arduino, I can't forsee regarding aligning the left side with the North Star using a) a compass b) lat/longitude sent via Bluetooth from Android. That's where I'm afraid there's some limitation i'm not yet aware of.