Monday, December 19, 2011

GOTO Mark-X: Improved motor mounting

The initial mounting method has been quite ugly and ad hoc, so I took the plunge to go back to my original design. That is, to drill a hole on the original motor cover in order to fit a long bolt to connect to the mounting hole of the Mark-X. The drilling hole couldn't be too accurate since I don't have the proper tools and skills. Therefore, I started off with a very narrow drill bit so that I could refine the position after the initial drilling. After the initial drilling, I found that I am pretty on-spot and it should be accurate enough after fitting it to the mount. A good sign, but a drill bit was killed during the process which was expected. That I changed for a thicker drill bit to do the final drilling. It turns out to be accurate enough especially I was using a flexible shaft coupler which allows a little bit more tolerance. This is the final product:

Pretty elegant, right? In order to fix the motor in the field, all I will need is a small hex key to engage the shaft coupler and then I will need to fix a small nut at the other end.

Actually, the bolt head was a little bit too thick to hide completely inside the motor cover, but then it's just a little bit over.  You can see from the photograph below that the motor cover was not completely hide below the black compartment, but it's fine enough.

So far it's one of my best DIY projects.  I'll do a beta testing soon by using the sun as my target.

Next Step: A Better Mounting Plate
  1. Lighter in weight
  2. Allow balancing
  3. Cheap and simple 

Update 2011-12-19:

I've inserted a nylon locknut on the other side of the mounting hole on the Mark-X, it further fixed the motor in place.

For the mounting plate, I tend to keep it simple and stupid in order to keep the cost low.  Currently, I'm thinking that I might give up the facility for balancing by sliding since it is much simpler to make, and it's far more compact for transportation.

In order to alleviate the problem, I will keep the mounting plate very short so that the torque due to imbalance would be reduced.  Secondly, I can always hang the battery pack or attach something else on the lighter side to enhance the overall balance.

I've some ideas in my mind by using short angle aluminium plate and I've some scratch materials at home so that I could do some testings without cost.  The only problem is whether the vibration damping would be good enough or not, and also the varying degree of flexure during tracking.

I believe this idea would work, the problem is the choice on material.

I guess thicker angle aluminium plate would work, the problem is where to buy them.  If that was not strong enough, I think thicker aluminium bar will do the job, the problem again is sourcing.

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