Dome Panel Automation

I was excited to automate the dome panels for a while. I already had the panels all cut and the hinges mounted.

The next step was to mount the servos securely. Since i cut my dome in 2 pieces, there wasn't really a way to just stick the servo to the inner dome. I saw on Chris's blog over at http://www.artoo-detoo.net that he made little servo mounts from angled aluminum. I basically used the same idea but i only had square tube in hand. I just hacked it in half and made some angle out of it. A little ugly but works.

And with a servo mounted. I'm using HS-65 MG servos. These are sub micro with metal gears and the seem pretty good. 

Next I had to build the linkages. This was pretty easy i just bought some parts on hand at the local RC car shop.

Here is the part breakdown. If your interested in using the same linkages. 

1. 2-56 Threaded Rod ---------------------------------------------------------------------$1.20
2. 4-40 Threaded Rod ---------------------------------------------------------------------$1.20
3. 2-56 Safety Lock Kwik -Link Linkages DU-BRO #815---------------------------------$2.39
4. 4-40 Nut---------------------------------------------------------------------------------$0.02
5. 4-40 Lock Nut---------------------------------------------------------------------------$0.10
6. DU-BRO heavy duty 4-40 E/Z Connect  #490-------------------------------------------$2.29
7. Spring from assorted spring pack from home depot (one box will do whole dome---------$4.40
8. 3/32 Plated Brass Dura-Collars #138----------------------------------------------------$1.89

Instructions:
-Cut the threaded 4-40 Rod so that a nut will fit outside of the hinge.
-Remove the pin and lock from the 2-56 Safety lock kwik-links and drill the hole larger to fit the 4-40 make it kinda snug.
-Expand the hole in your servo arm just big enough to fit the E/Z Connects  through.
-Assemble rest as seen here.  Trim off the extra 2-56 rod.

Here's a couple vids with some test movement.

Dome Sanding and Polishing

I thought i liked the spin lines on my dome until i saw some other Bay area Droids, Specifically Capodimusica's and Chris's.

This made me wanna sand out those spin lines. This wasnt too fun i must confess but heres how i did it.


I used 220 grip sandpaper on an orbital sander and this quickly removed the spin lines. Probably 5 minutes for the whole dome. I sanded it on the frame so i could spin it on the rockler bearing. I also used a plastic bag over the inner dome to keep all the gunk out of it.


220 Orbital Sander


Next i hit it with 320 Grit on the Orbital Sander. This was pretty quick as well.


After this i moved to 400 grit wet dry and went in circular patterns. I used the pie panels as reference where i started and did one "pie" section at a time. I used 1/4 of a sheet for each section.


Next the same but with 600 Grit


Then 1200 and one more time at 2000 Grit


Once this is done i took some Mothers Mag aluminum polish and a cheap harbor freight buffer and buffed the dome. Once the polish starts turning black you then just buff it off with an old tshirt etc. The more you buff the shinier it will get.

Looks a bit different in person, ie a little less shiny, but here's the result. I think just the right amount of shine.



Now i gotta do the panels ugg...Also what mess...