Crashing a fundraiser...for a good cause!

Last Saturday morning, I received an email from a friend asking for my help...a mutual friend lost everything in a house fire.  Her son, Remmington (14), is a huge R2-D2 fan and all of his Star Wars stuff was destroyed in the fire.  My friend wanted to know if it was possible to get R2-D2 to the benefit support in 7 days.  I said yes, we'd be there!

Now, if you have followed the blog entries, I have had R2's dome completely apart.  I've been hinging all the top panels, adding servos, linkages and had just begun completely re-doing the wiring.  I had my work cut out for me to get R2 working!

I pulled several very long evenings getting the electronics re-located and working on the crazy wiring I've had since I first put R2 together.  It was a lot of work...but...we were ready to go! 

R2-D2 was the surprise guest.  Only four people knew that we were going to show up and surprise Remmington.  Once we arrived at the school the benefit was being held at, we snuck in a side entrance and hurriedly got R2 setup.

Earlier in the week, I posted to the R2 Builder's forum letting them know a great R2-D2 fan lost everything to a fire.  Knowing how expensive the Hasbro Interactive R2-D2s are, I wanted to see if any of the builders had one they were willing to part with.  One builder did have one and wanted to give it a new home...plus help Remmington rebuild his Star Wars collection.  "Darth Miller" shipped over a box full of collectibles along with a Hasbro R2-D2.  Others sent monetary donations.  Us R2 Builders make be nerdy...but we have huge hearts.

We had a great day mingling with the kids...big and little...and spending a lot of time answering Remmington's many R2 questions!  I'm certain it won't be long til he start researching and building his own!

 

Installing servos into the dome...and other changes

Installing the servos into the dome was a pretty smooth process.

First, we attach the micro servos to the aluminum servo brackets.  I really like the Lynx motion ones.

In the last blog entry, I detailed the linkage that will go from the servo to the hinge.  Now, with the servo and aluminum bracket together, the servo horn and linkage are connected.

Next it was time to adhere the servo & bracket to the inside of the dome.  While I used the impact-resistant, gel Super Glue on the first one...I decided to go with something I know well....JB Weld.  I know if ever had to remove these, I could with JB, without damaging the dome.  

The next day, it was time to make some changes inside the dome.  With the addition of the Life Form Scanner and Periscope coming soon, available space in the dome really needs to be tweaked!

The rear PSI (Processor Status Indicator) was taking up too much space using the PVC pipe piece.  We need to use something else...a diffuser block offered by the gents of produce the dome.

Mounting the light to the PVC was a matter of drilling and tapping two holes (4-40) and using some leftover plastic servo mounting pieces that come with most servos.

Next up was the ServoCenter card.  I attached aluminum mounting feed to the bottom and JB Welded that to the dome as well.

The same was done to the JEDI light system...anything mounted on the plastic dome ring needed to move ...

The power fuse block still needs a new home...and that's in the next post, plus more.

Creating a servo-saving linkage for the pie panels

I'm still working on R2's dome and getting everything situated with getting the hinges linked up to micro servos.  In the previous post, we got the hinges in!  Now, its time to figure out a reliable linkage from the micro servo to the hinge itself.

One thing I have noticed with my R2 since adding hinges and servos to the various doors and panels has been making them close snug.  Another thing I was worried about was servos being damaged by little fingers forcing doors open!  Adding a spring to the linkage would allow the doors to close better...and if pried open, the spring would give a bit before applying pressure to the servo.

I have seen how other builders have assembled similar linkages or just used a spring.  I wasn't able to bind a small enough spring that was firm enough to work.  So, I mimicked a setup I have seen others us.

Here's what it looks like when complete:

Here's the process to build it.

First I remove the plastic servo horn and drill out the first hole with a 3/32 drill bit.  The DuBro EZ connector is a 3/32 model.  To hold it in place, you need to use a hammer and tap the connector into the retaining clip.

Now we need to get our push rods ready to go.  I am using 12 inch 4-40 sized push rods that are threaded at the end.  Since we need the linkage to be small enough to fit inside the dome safely, we have to remove some material.  I remove 3/4 of the threaded section since we do not need all of it.   I trim the other end after I have the linkage made....just in case!

 Now I need to install the linkage that will go from the hinge to the push rod.  For this I am using DuBro Adjustable ball links (short, 4-40).  These will allow for some pivot and since they are shorter than the regular ones, you need less push rod.

 Next up is to slide a 3/32 collar on, the spring, slide onto the EZ connector, the spring and a collar on the other end.

 The springs need to be compressed...well, ok...squished...to the point they have some movement but aren't sloppy.  Clear as mud, right?   The point is you want the servo to move and push the push rod, not slide around the spring.  But you need to balance it out so it has a little give...as we are using the spring to help protect the servo and help keep the tension on the connection.  Your mileage may vary depending on the springs you use.  This is a lot of trial and error!

Once you have that trial and error sorted out THEN you can clip the end of the push rod.

Rinse and repeat a few more times!

Next time, we'll cover installing these into the dome!

 
 

Hinging the top dome panels

As many R2 builders can attest to, there are parts of the build you dread or just opt to put off to another time.  For me, this was a little bit of both.

Hinging the top dome pie panels is tricky.  You have a curved surface (the dome) and are trying to make a curved piece (the panel) line up.  You need to remember all that geometry you learned in high school plus use some clever methods to test things.  

When I first put R2-D2 together, I was racing to meet a Halloween deadline in 2009.  I did make the cut outs to the inner dome and used silicone adhesive to attach the top panels to the dome.  I did not keep the cut outs as I was under the impression they were not needed.  Oh how wrong I was!

That said, I needed to remove the silicone adhesive from the inside of the dome in order to free up the panels.  I found some spray on stuff at Lowe's that removes silicone adhesive and spray foam.  

Before we start spraying, we want to protect the dome panels on the outside.  We don't know if this spray will eat paint or damage it.  

One pie panel is already hinged so we tape the top so it can not pop open.

Here's how everything looks before we begin...

To be safe, I am also going to cover up the hole at the top with painters tape too.

The tools needed with me a plastic and metal scraper and plenty of paper towels

The spray states that it reduces the molecular bond of the silicone adhesive.  Its more or less a spray on gel, so be sure to wear protective gloves so you don't get this stuff on your hands.  After letting it set for 30 minutes, I used the plastic scraper to gently pry the silicone off.  Some pieces came off to large clumps, others took a bit more work to pry off.

I had one panel that had a really thick layer of silicone that required a lot more force than I was comfortable using.  I decided to spray a heavy layer of the remover and let it set overnight.  The next morning it was significantly easier to pry away.


Here's how it looks after scrapping and then using a spray bottle with water in it to clean the affected areas (note the panel labeled One is staying attached for now)...

I flipped the dome over and began to slowly remove the panels and tape.  I removed the tape from the panels so any residue could be cleaned off and then put new tape back on.  We'll want to protect that paint for the clean up on the other side.

Next up, we want to sand away any left over residue using the dremel sanding head.  Once cleaned, we can use some scrap aluminum (from the body skin cut outs) to add some material for the hinge point.  This will help make sure the panel sits flush with the outer dome.  I'm using Loctite Super Glue which is a gel solution...and it is also a more vibration resistant formula, which should help!

 The nice thing with superglue is the fast drying time.  Just to be sure, I let it stay clamped for 30 minutes since the basement is only around 50 degrees or so.


Now it is time to match each panel to its respective opening (you DID label them, right?).  On most of them, I cut out a bit too much material from the inner dome, so lining up the panels is extremely intricate work!  Once in position, tape securely and move on to the next.

I know from experience with the hinges that I generally want the hinge to attach to the lowest point on the pie panel.  Just to err on the side of caution, I am going to use the high strength (10 pound) double sided foam tape from 3M.  I am going to adhere it to the lower portion of each pie panel piece (well, the piece I glued to each).  Then, I'll place the tape on the bottom of each hinge.  What I will do is start at the pie panel attachment, then gently attach the other portion of the hinge to the inner dome.

The red is the plastic material on the tape.  It is removed before adhering the hinge

 After each hinge has been placed into position, I gently turned the dome over and very slowly , removed the tape to see if the hinge opens smoothly...

Success!  So we know the hinge placement will work.

However we need to check how the panels line up and I know right off I need to add another layer of material where the hinge attaches to the panels.  Easy to do, superglue another layer of aluminum scrap to it.

Then its time to permanently attach the hinge to the panel.  What to use?

I opted for JB Weld.  Why?  The hinge will be visible when the panel opens.  I can sand JB Weld and clean up the panel later.

After taping all the panels down again and flipping the dome over, its just a matter of gently removing the adhesive from the pie panel hinge, dabbing some JB Weld in its place and slowly pressing the hinge into it.  Be careful for oozing...you don't want it drying and jamming up where the panel opens.

 For the hinge-to-inner dome portion, I decided to try something odd...I left the double sided adhesive on and place JB Weld on top of it.  Why?  I do not want to remove material from under the hinge since everything lines up well.  Will it work?  We'll see!

24 hours later...

Next time, we'll work on getting micro servos and a decent linkage assembly together!