Monthly Archives: August 2013

Happy Birthday!

Happy Birthday Greg!  Of course I didn’t know that when I stopped by at 9am on my way to New Jersey to pick up parts.  We were headed up for a family reunion and figured since Greg is about an hour north and we’d be passing by, I’d see if I could pick up parts from him.  Of course he said yes.

Felt bad when I realized it was his birthday – if I would have know I’d have at least brought him something from Dunkin Donuts or Starbucks given the early hour.

I picked up the dome gear and a few other pieces.  The material for the dome gear was $25.

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Dome gear

Costs:
Dome gear: $25

It’s Alive!

As more and more parts are nearing completion, I couldn’t resist the urge to get R2 moving.   I’m using the VEX Controller and the Dimension Engineering Sabertooth 2×25 which I purchased for $125.

Here is a short video of R2 moving around.
https://docs.google.com/file/d/0B4LWQv07hDIQS2VzQWRxWmVEckk/edit?usp=sharing

You can see I still haven’t completed the center foot.  With all the chamfering involved I just don’t want to start on it, been procrastinating.

Costs:
Motor controller (feet): $125

Speaker arrived

Thanks to Prime shipping the Bluetooth speaker arrived this past week.  I’ve constructed a box out of styrene to hold the speaker in place inside R2 immediately behind the top center vent.  I lined the holder with felt to help minimize any vibration from the speaker sound.

The holder screws to the horizontal frame directly under the top center vent.  The speaker is inserted and then the back piece screws to the holder to keep the speaker from falling out.  The center vent prevents it from moving forward.

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Battery Boxes

Assembly of the battery boxes went fairly quick.  Again, I used the laminate trim bit since the final shape is all 1mm skin.

One modification I made was for the wires between the ankle and the foot, I decided to run them through the battery boxes since mine will be empty.  I used a 1/2″ styrene tube that I glued to the ankle and cut a slot in the battery box for it to pass into.  I also made the shape so that the ankle could swing up for 2 leg mode (the way I intended to display R2 in my Star Wars room)

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The inside of the battery box showing the path for the wire.

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This picture shows the 1/2″ styrene tube that goes between the ankle and the battery box, this way you don’t see any wires.

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I decided to use these hex thumb screws to attach the battery box covers.  I just like the look, gives it more of a ‘real’ look in my opinion.  Plus I can just take off the screws without any tools.

Skin me

I’ve been working on cutting out the pre-scored skins I purchased from Greg for $60, he had previously ordered these and won’t be using them.  Cleaned up a lot of the openings with the file so they were square, if the mis-cut was too much its now battle damage.

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Spent last night taping the skins into place, but it was too late and I was too tired to actually glue them.  Woke up early and just had to glue them in place.  I bought the skins from Greg who had bought them from Izzy who bought them from a run on Astromech.

The glue applicator from ePlastics seemed fine for gluing the 2mm and 3mm sheets, but it put out a lot of solvent which made the 1mm warp.  I went to my local hobby shop and picked up a small needle applicator to use on the skins, dome and various parts that are wrapped with 1mm.  The needle applicator was $6.

Needle applicator

This is just the inner skin, I have a lot more work do to on the outer skin before its ready to be glued into place.  I mistakenly cut out the center vent piece, the entire rectangle on the inner skin, oh well again thankfully styrene is more forgiving than aluminum.

My first pass at gluing the skins, I was very judicious in the use of the glue not wanting to warp the skin.  However, as I usually do I couldn’t leave well enough alone and thought that most of the inner skin would be covered by the outer skin.  So I applied more glue along the frame members as I know the skin is part of the structure of the body.  Problem is that the four back panels are only the inner skin, and I could warping along several of the members.  Oh well, a little sanding, weathering and heck that side faces down most of the time – you’ll never notice.

Tip:  Be careful on the back inner skin as most of this is exposed, unlike the front.  If I was to do it over, I’d add another inner skin so those areas are just as thick as the rest of the skin and you’d be able to cover up any warping easier.  Or just use less glue, but you really want this to be strong.

Not sure if it was my cutting, gluing or if the pieces were just off, but I had a few pieces of the frame protrude into openings.  The one below is on the center vent, but had similar issues on both side vents.  Again, styrene is very forgiving so I’ll be able to fix these fairly easily.

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Oops!

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All taped up

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Inside view of my mistake

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Rear inner skin

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A new tradition?
I work in the construction industry, and part of our tradition when we build a new building is to place inside a wall cavity something with the year the building was built.  Usually its a dollar bill or a quarter.

With this in mind, when attaching the skins I realized there was going to be a small area that would be completely sealed by the skins.  I put a shiny 2013 penny into this area right below the side vents before gluing it in.  Now when you move my R2 if you listen closely you can hear the penny move back and forth.  You’d never notice it if I didn’t point it out, but I felt it was important as someone in the future may dismantle him – and there will be a piece of history from when he was built.

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Costs:
Laser cut skins: $60
Needle applicator: $6

Main Ankle/Foot Hardware

For the Main Ankles I’m using a 3/8″ threaded bolt, 2″ in length with a steel sleeve for the connection between the main ankle and foot, I didn’t want the bolt threads wearing away the styrene.  The bolt has a 9/16″ head which I’ve marked for easy of finding the right tool in the future.  I glued the washer onto the styrene facing the battery box, but there is not enough clearance for the nut and washer on the outside face.  I’ve drilled a hole in the battery box to allow access for the bolt to be inserted and access to the hardware from that side.   It is tight on the outside so getting the nut on the bolt is tricky until it starts getting threaded.IMG_2737IMG_2738

Here is a picture of the bolt/nut installed, notice the 9/16″ again on the inside so I get the right wrench the first time.

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Motors
I’m going to be using the Jaycar motors ($40/each + $25 shipped) for both feet and the dome as recommended by Dave.  I bought a 7mm/8mm ratchet wrench from Sears for $7.  It works extremely well for attaching the motor support plate to the foot.

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Wheels
I ordered the wheels (T80P-493BG-HS6) and hubs (T80H-SM61) from BaneBots for $37 shipped.

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Costs:
Motors: $105
Wrench: $7
Wheels/Hubs: $37

Center Foot & Ankle Hardware

Looks like I’ll be going with SAE bolts for the ankle/foot hardware since larger metric bolts are as easy to find at Home Depot or Lowes.  I also didn’t like the ide of threading the bolts into the styrene so am going to use a bolt all the way through with a metal sleeve to prevent the bolt threads from wearing on the styrene directly.

I’m using a 3/8″ threaded bolt, 2″ in length with a steel sleeve for the connection between the center ankle and foot.  I’ve recessed the washers and glued them in place on both the bolt and the nut side to give more metal bearing on the styrene.  Since the area is too tight, I cut out the left side panel to allow access to the hardware, it reattaches with rare earth magnets I bought at Amazon.

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Center ankle hardware

For the caster, I found a 3″ Waxman rubber caster at Lowes.  Wheel diameter is 3″ and the mounting height is just under 3-1/2″.  LINK

I had to make my own ‘wrench’ out of styrene since there was not enough clearance for a regular wrench.

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Costs:
Center Ankle hardware: $7

What is an R2 without sounds?

I’ve decided to stick to the budget sound system of an old iPod connected to a Bluetooth speaker.  I downloaded the sound files from the Yahoogroup and loaded them on my iPod, made an R2 Show playlist which I’ll use to give R2 a voice.

I purchased a SimplyVibe V3-5CPB Bluetooth speaker from Amazon for $38.  It has a Li battery that should last a good time, it also has a stereo jack for an additional input which I can connect the ThinkGeek system to in the future.

speaker

Costs:
Speaker: $38