More upgrades for R2-D2

Well Santa was good to me and R2-D2.

Over the last few days, I have had a chance to purchase some electronics for more improvements in R2-D2

Below is a ServoCenter USB to Sevo Controller board.  This one card allows me to control 16 servos.  If I wanted to daisy-chain several cards, the cards can control up to 256 servos!  The card has excellent technical support of programming support for Visual Basic and Visual C#.  I currently have a program that handles the sounds on a Windows wireless game pad.  I would like to control several of R2's panels, doors and so forth using the gamepad.  This saves me from having to buy a more expensive radio to have this ability via more channels.

Another change is replacing the 12 volt 7amp battery being used in the dome for the electronics.  I found two very small 6 volt Werker batteries I am going to try running in series.  These are small enough to fit within the inside lip of the dome, secured to the plastic ring inside of it.

And finally, some pieces for R2's onboard computer.

The first is a USB to Serial Port converter cable.  The Netbook does not have any serial ports, so this will allow it to connect to the AX3500 controller card.  The cable that came with the controller card is a serial (9 pin) connector.  Now I can quickly connect to the controller card to make changes or read settings and logs.

The last item is a non-powered hub.  The Netbook only has 2 USB ports and both are currently in use.  One has the gamepad plugged into it while the other powers the external speakers.  With the addition of this hub, there is now room for the ServoCenter to be plugged in.

Complete tear down and upgrades!

The time had come to do a teardown and inspection of R2-D2, to get a better idea of what was working well and what was not.

One of the major issues I wanted to address was the body sway I was seeing.  The source of which I thought was limited to the center foot having problems with its casters.

I also wanted to find a way to build some sort of shock absorber into the the center ankle or foot.  Whenever R2 rolled on uneven surfaces, the crash and clang was rather severe.

One thing I stumbled upon while looking for a way to solve this was a rubber muffler hanger.  This piece is about the size and thickness of a bar of soap.  Cut in half and it would not only fit well, but would also make R2's feet level.  For $4.99, it sure looked promising!

Finally I slowly took everything off, getting down to the frame.

One thing I noticed right off was a few of the screws holding the skins on were missing or very loose.

Upon inspecting the frame, I went around each frame rod and plate, checking for snugness.  The horizontal piece ath shoulder level was very, very loose.  Other frame rods required a few turns with the screw driver.  This was a big part of the swaying I was seeing.

To help stabilize the frame, I decided to put back two vertical frame rods that I had removed eailer.  The rods were located in a spot that would prevent hinges from being installed on the large, vertical doors on R2.  There are 4 large vertical rods that I removed.  To even the load, I put back two, with one in the front and one in the back, diagonal from each other.

The center foot was next. 

One thing that I checked first was the bearings that allow the caster to rotate.  It was very clear that they were in very poor condition.  When I tried to spin the casters around, they did so but not very freely.  Imagine 150 pounds (or more) on them and I can see why its been such a struggle to get R2 rolling. 

I beleive the problem is the holes I drilled too close to the groove near the bearings.  In order to mount the foot plate into the foot, the bolts had to pass thru the casters. 

The replacement casters are the same size as the previous ones, 2.5 inches.  They seem to be the same material, just a different color neoprene.

This time, rather than trying to drill through the casters at all, I came up with a better idea.  I decided to run 1 inch long (10-24) screws and using a lock waster and nut on each.  This way, when I bolted the mounting plate into the center foot, there would be 8 screws pointing upwards.  I placed the rubber muffler mount I cut in half in the middle of each, then slid the casters into position on top of them.

Without too much force, I then used a small washer and a lock nut on each until the casters were snug and level....now the casters have the rubber 'shock absorber' them and can ride up and down a bit as needed....

Once I had R2-D2 all back together, I had another thing to do....pick up the great Santa hat my Mom made!

Looks good, yes??

Getting ready to improve the center foot & ankle

A quick post for tonight...

Tonight I hit Lowe's to pick up some pieces I want to test fit into R2's center foot and ankle.

First, the rubbergasket is used in plumbing. Other builders have cut these up and used them as a rudimentary shock absorber. For $7, its worth checking out.

Also, I want to see if different casters work any better. These are 2.5 inches like the current neoprene ones.

I'll start working with these over the next few days. I have some other ideas I would like to test but I need to find the right pieces first.

R2 is home, survived his first outing!

R2-D2 is back home after spending just under a week at my workplace.

Last Friday R2 got to visit with the children in the Pediatrics Floor and Pediatric ICU. Over the past few days I've been battling a sinus infection so I was out a few days. R2 had the conference room all to himself! However word got around that there was an R2-D2 around and before you know it, staff and kids are showing up with camera phones! Ha! Awesome...!

Between some battle damage from the transporting process, R2 has some pretty good dings from banging into things. In this picture, you can see on the right side a bit of paint missing from a shoulder. That's from a poor attempt to get out of the elevator by gunning the throttle to get over the door lip. (The elevator is sporting a minor ding too, so the "fight" was a draw!)



As mentioned in the previous blog post, its time for a tear down to check everything out. Some of the skin screws have popped loose or jiggled out completely. R2 has a fair amount of body sway, mostly related to the center foot casters being problmatic. I need to log all the 'issues', video how its driving around now so I have a reference for when I make some tweaks.

Finally...if you think you find a great, cheap solution....be careful!

I bought these cheap, $9 moving casters as they were touted as each 'being able to handle 200 pounds each'. Well, take a look on the left side of the photo below....

The problem, asides the collapse of the casters under the structure, is that the wheels are tiny little plastic ones. They rub along the inside of their metal brace and due to their small diameter, get stuck and jam on the smallest of bumps and cracks.

While I would like to make something more elaborate, I now have a simple moving dolley. A rectangular shaped wooden structure with 4 large casters!

Anyone want 3 slightly bent moving casters? :-)