I received my dome drive system today and I’ve already gotten it installed and working. I still need to wire it up to a speed controller, but that should be relatively easy and I’ll work on it tonight when I make the frames electronics mounting panel.

With all the dome work yesterday I had time to think about it’s electronics and how I’m going to lay things out.

I’ve seen some people bond the dome ring to the dome, but I don’t think it’s such a good idea for me. For one I’m using the dome base plate that supports the periscope, and I’m thinking I’ll attach other things to it as well. The base plate is also bigger than the ring and it restricts access from the underside, so there would be no way to get in and fix a lot of things.

So the dome will split in two and I know have the dilemma that I’ll need decide where to put some things, either in the base or up in the dome, and then worry about running wires. For example, only the lift mech needs to attach to the dome plate, and it makes sense to put the weighty batteries down there too.

Initially the dome will contain the following this that are powered

• Power Distribution Board – 12v in, 9v, 6v, 12v out
• Front Logic -9v
• Rear Logic – 24v
• PSI’s- 9v x 2
• Holo Projector Lights – 12v x 3
• Vex Controller for Periscope Lift Mech – 6v
• Batteries – 2 x 12v
• Lift Mech Speed Controller – 12v

Later on I’ll be adding a few servos attached to the panels.

I think I’m going mount most everything on the dome base plate and run 3 power lines up into the dome with quick release.

Here’s a rough idea on layout

Today was dome day…. Actually it was almost the entire weekend, but “Day of the Dome” sounded so much better than “Dome Weekend”.

I’ve made a lot more progress in the last few days and more confident that I can get the dome glued together in the next week or so ready for C4.

I’ve had a long list of to-do’s for the dome and been putting things off waiting for other bits to fall into place. The frame was holding me up for the longest time. Now that it’s pretty much done I could go back and work on the dome.

I installed Rockler bearing a week ago and it’s working great now after a few tweaks. One of the issues was the damn dome ring again. I thought I’d seen the last of problems with it, but the inner circle that’s tack welded on the inside is all warped/wavy so when I put it on the bearing the dome ducks up and down as it spins. Luckily I had to bolt the periscope life mech dome base plate to it and it helped level it off. It still needs tweaking but I’ll wait till the I have the skins on.

On Friday night and Saturday morning I decided to tackle fixing a wiring problem in my periscope lift mech rather than sending it back to Daniel. He kindly offered to fix it but it would mean that I would be delayed again from working on dome stuff.

I removed and disassembled the Delrin block holding the switches on Friday night, and a quick test showed that diodes had blown. I had to wait till Saturday morning for Radio Shack to open, but the good news was the new diodes were only 89 cents and about and 30 minutes work to get installed.

Next up was a bunch of fixes to the holes I’d cut in the inner dome a few months ago. When I first cut them I had the older aluminum Holo Projectors and resin Front and Rear Surrounds. Well now I have new HP’s and aluminum Surrounds, and everything was a tad bit bigger and I needed to tweak the holes.

I used a bottle wrapped in sandpaper to widen the HP holes.

I also had to adjust the hole for the new Rear Logic.

Notice I’ve yet to cut the rear panels from the dome. I’m still using them as a guide to make sure everything while line up with the holes on the inner dome. I’ll probably cut them out this week now that I’m happy with the fit.

Next up was the dome ring. I needed to cut some notches in it to allow the PSI and HP’s to sit flush with the dome. I marked, dremel and filed out where I needed to the space.

I decide to tackle the periscope housing next even though I have a new aluminum one coming in the next few weeks. The PVC kit was still in pieces on my workbench but I really needed it to figure out how much bigger I needed to make the dome pie panel hole I’d miss sized a few months ago. So I quickly tacked it together with super glued and installed it on the now working lift mech.

Once done this allowed me to go back and adjust the dome pie panel hole that was too small. This is a real bad picture, but I’m trying to show that the periscope now passes through the opening without any problem. I’ll try and take some better pictures tomorrow.

At this point I almost started to cut the remaining holes in the dome, but decided to finish the PVC periscope kit and add a lens. I’d already done a lot of work on it in morning and I was so close to getting it done. Finishing it up would have two advantages, 1) I can make sure that it really does fit after squaring off the edges, and 2) if the aluminum one is delay at least I have a backup for C4.

For the lense I cut out a small square of acrylic and then rough sanded it into shape with my bench sander. I really should have used a thicker block, but all I had was 1/8″ acrylic. It really didn’t take long, so I may go back and make another later this week.

The fit was good

Next I marked out where I needed to sand down on the bench sander. Please be careful that you don’t push your fingers into the disk!

Here it is after I’ve sanded down the edges. Not pretty but I wanted to show how you can go from rough piece of plastic to something shiny in a matter of moments.

Here it is after some quick sanding through various grades of paper

And then polished up on my bench grinder with a polish wheel.

Next up was sanding and bondo’ing the housing ready for painting.

Almost done. I applied a layer of undercoat, sanded and undercoated again.

In the morning I’ll probably sand an prime again before trying the top white coat.

I also need to glue and pain the resin riser pieces, but I should be done tomorrow night. I can then think about adding the LEDs.

A few nights ago I finished the last few parts of my frame structure and also constructed a real battery harness that will sit above the center leg mounting plate.

It will hold 3 standard 12v 7amp batteries in the droid a nice low center of gravity. I’m hoping the design will allow easy access for charging and removal.

The bottom plate is the center foot mount and attaches to frame ring #4.

It’s based on a photo I saw on this site and thought it was a good design to hold the batteries.

The Vector 1089A Battery Charger I’d ordered last week just arrived. It’s a lot smaller than I thought it was going to be – so small that I’m tempted to rethink how I’m setting up the electronics. I think I could fit it inside the body rather than use it as an external charger.

I made a start today on mounting the electronics like the speed controllers, Vex Micro controller, Fuse Block/Circuit Breaker, Power Distribution Board etc.

At first I was pretty sure I could fit everything on the plate I’d cut and mounted. I’d done some rough measurements a few weeks ago and it looked like everything would fit on one side.

But today I laid everything out and it’s just too tight, especially when you start wiring things up it’s going to get ugly fast.

I think I’m going to move the CF3 Sound Card and RF Remote to the back (inside) of the mounting plate.

On a tip off from a fellow builder I bought a few of these cheap motors for $45 vs $150 for the NPC-2212’s.

I already had my NPC-2212, but thought these would make for good spares, and apart from the extra holes and a longer drive shaft they’re a perfect match.

The NPC-2212 is on the right with the long leads and the cheap OEM motor on the left. Click on the image for more photos.

They can be found here.

Your mileage may vary!

I got to test a few of the satellite motors tonight for the first time. There’s an enormous amount of torque in them, but before the motor will turn you have to release the break using the white and black/white wire connected to a 12v or 24v battery. You should hear a snap or a click when I releases.

The motor is an integral part of many peoples 2-3-2 leg design, or even straight 3 leg designs, mostly due to the very popular JAG frame. I’ve yet to see anyone use them successfully in a 2-3-2 astromech, and heard some horror stories of people who have tried and failed. I’m hoping we’re going to see some working 2-3-2 implementations at C4 that overcome the shortcoming of the motors. But I’m not going to hold my breath.

I’m still not sure I’m going to use them right away, if at all. The major drawback with the motors is that on a heavy droid the gear teeth can sheer under stress. It’s not so much from stationary rotation of the legs/body, but when driving the droid around. The only thing hold the leg in that position is the small number of teeth that are engaged in the gearbox, and the inevitable happens.

Robert Ross has a prototype design for an external mechanical lock mechanism that will removes the stress on the gearbox. I’m trying to decide if I want to fabricate something similar or wait and see what happens after C4.