Friday, March 13, 2009

TG-SP II Project Continues...

When it got started, you will move on. Last night and this morning, I spent some more time to do more work on this project, here are the results:

In short, the motors are mounted on the plastic board. The holes that I drilled yesterday were enlarged, since I need to put in the mounting screws. There are two mounting screws for each motors. The holes for the mounting screws were made by using a low power soldering iron.

Inline shaft couplers were attached to the motors.

So, it's ready for some basic testing. I just applied 6V and 12V DC to the motors, trying to see if the mount moves correctly:

Yes, they did! They slew slowly, good enough for guiding at 6V. They slew faster at 12V, but it's still a bit too slow for general slewing, but then it's not the main purpose of this project.

I have continue the test for several minutes, and then reverse the direction of the voltage and it works flawlessly as expected.

However, there is a problem. The plastic board is too thin, and the hole is not perfectly aligned with the control knobs of the mount, so I found that the board would flex periodically slowly when the drive continue to work.

That's fine for manual motorized guiding, but for autoguiding, would the software would be cheated? I think no since the adjustment is always guided with a CCD, and therefore, the flexture could be absorbed automatically. It will just affect how fast the motors could response to any tracking or polar alignment errors.

However, that periodic movement would greatly affect the amount of backlash... And actually, it's exactly a huge source of backlash.

So, could the project continue? Yes! At least the current setup which I'm now making could be considered as a prototype for the proof of concepts!

If it works, I shall migrate everything to a metal board, with better mounting. Better mounting should probably required, since the motors are now fixed by the control knobs of the mount only.

Let's see how it works out eventually.

Next steps:

1. Attach the driving electronic (a Solarbotics board)
2. Design the control box with a variable resistor to control the speed of slewing

But since I don't have any autoguiding interface, autoguiding will be the next step... but then since the Solarbotics board should accept autoguiding signals without problem, and therefore, the autoguiding part should be just some simple soldering work.

That is, if motorized manual guiding works, autoguiding will work with minimal amount of work!

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