The Comprehensive Guide to Building a Realistic R2-D2 Replica
Join a club of Makers sharing CNC and 3D printed parts, to construct your very own, full-size astromech droid. You know you want to!
(A) Periscope (B) Life Form Scanner (C) Radar Eye (D) Pie Panels (E) Processor State Indicators (PSI) (F) Front Logic Displays (G) Dome Panels (H) Holoprojectors (I) Large Data Port (J) Utility Arms (K) Front Vents (L) Coin Slots (M) Coin Return (N) Ankle Cylinder (O) Skirt (P) Power Coupler (Q) Octagon Port (R) Battery Box (S) Under Shoulder Detail (T) Rear Logic Display (U) Shoulder Hydraulics (V) Shoulder Horseshoes (W) Shoulder Hub (X) Booster Cover (Y) Shoulder Buttons (Z) Ankle Bracelet (AA) Leg Strut (BB) Ankle Cylinder Wedge (CC) Drive Units (Feet) (DD) Foot Hoses
If you’ve been to a Maker Faire you’ve probably come across one or more full-size R2-D2s roaming about or partying with the DJ, chirping and bleeping like the real thing. These robots and other Star Wars “astromech” droids are built by people like myself who are part of the R2 Builders Club. Some of us are crazy for robotics, some just want a screen-accurate replica of their favorite Star Wars droid, and for many of us, it’s both — we love that we can build a real robot that’s an iconic character.
When people encounter R2-D2 they go through stages of surprise, happiness, and curiosity. After a few minutes of ecstatic picture-taking with R2, their curiosity kicks in. “Did you buy it? Did you build it? Is it a kit? How long did it take? Can I build one?”
Yes, you can.
This R2 by Andrew Radovich has over 144 3D printed parts. Photo courtesy of Jennifer Micheletti from Roadside Morning Glory
The R2 Builder’s Path
R2-D2 is not for sale, and there is no complete kit available. However, anyone can build an R2-D2. The R2 Builders Club (R2BC) maintains an official set of blueprints, and our members make and share parts. Don’t worry if you’re not a skilled builder. If you don’t have a particular skill, you can learn it. That’s the Maker spirit. Members of the club are always willing to share knowledge and techniques. If we can do it, so can you.
In this article I’ll walk you through a very typical R2-D2 build, so that you can get started building one too. We’ll focus on a simple and relatively affordable 3-leg, radio control setup, with dome lights and Bluetooth audio; you can always add functionality later. You just won’t believe how much people will love your Artoo.
The R2 Builders Club was started by Dave Everett in 1999 as a Yahoo Group to share information for “those interested in building a replica R2.” Today the club has grown to thousands of members around the world, with a Builders Council to moderate the forums and oversee the club’s official R2 specifications and part suppliers. Anyone is welcome to join, it’s free, and it should be the first step on your journey to building your very own droid.
R2-D2 built by Paul Gentile.
Jawa performed by Michelle Shank, 501st Legion, designation DZ-31013 Jawa ROTJ.
Why Build an R2?
Before you start, let’s discuss a few things to keep you from wasting your money and time and avoid the Dark Side. Why build a full-size R2-D2?
Because you can’t buy one. R2-D2 and its imagery are the property of Lucasfilm and Disney, and to date they have not granted anyone a license to produce and sell full-scale operating replicas. There are sellers on the internet offering a “full size R2” or parts. Stay away. The club forums are filled with threads from people who went this path only to find what they bought was not a quality product and that they wasted their money.
Because you have Lucasfilm’s blessing. From a legal perspective, the R2 Builders Club has a mutual understanding with Lucasfilm and Disney that we don’t exploit our droid building for profit. In turn, with years of good faith under our belts, we are allowed to continue with their blessing. That’s why we don’t sell droids or droid kits to the general public, and we have some rules around it all. The Builders Council is the keeper of the official R2-D2 specifications. Over the years, club members have had the opportunity to measure R2 units from the Lucasfilm archives, and the resulting blueprints have become our official guideline.
Because it’s fun! Anyone can buy something, but figuring out how things work and solving challenges makes it much more interesting. When you build your droid, it truly is yours and is infused with your personality.
PARTY ANIMAL: Everyone loves R2-D2 and can’t resist taking a picture with him. Here’s my wife, Maricel, and her friends — the usual scene at my house when friends come to visit!
How to Read R2 Builders Specs
When you browse the club’s documentation and discussions, you’ll notice three references that are important:
BC Approved stands for Builder Council Approved. Before anyone can offer parts to other members, they have to go through a review process to ensure that their parts are to specification and that they can actually deliver. (BC Continuously Approved just means the supplier doesn’t need approval for each new run of parts.)
CS:L and CS:R stand for Club Specification: Legacy and Club Specification: Revised. CS:L means that parts conform to the Club blueprints created in early 2000. CS:R is a 2014 update based on additional measurements from the Lucasfilm archives and production notes from the various movies. While most people will never spot the difference, these designations are important so that you know whether parts are compatible. For example the body height specification for CS:L is 19.563″, and for CS:R it’s 19.35″. If you go with a CS:R frame, then your skins are different too and you’ll need to use CS:R components such as the “coin returns” and large data port.
Our beginner’s build is CS:L, because I began it 4 years ago; today I’d choose a CS:R build because there are more CS:R parts available.
Before You Build
Building an astromech droid is a big project, but if you break it down into its parts it’s easily achievable. First, ask yourself these questions:
Which droid will you build? R2-D2 is popular but there’s a universe of astromechs to choose from. Do you want a droid that’s screen accurate to a particular movie?
What functionality will you include? Will your droid be static, radio controlled, or have some autonomy? Will its panels open? Perhaps to reveal accessories like a Periscope, Life Form Scanner, or even a lightsaber launcher? Will it be a 2-leg, 3-leg, or, most challenging, a “2-3-2” with a retractable center leg?
What materials will you use? Underlying all these decisions are money and time. The biggest driver of both will be the materials you build with.
Construction Materials
Aluminum
When Make: profiled the R2 Builders Club a decade ago (see Volume 02, “R2-DIY”), an all-aluminum droid might cost $20,000 and weigh more than 300lbs. As the club has grown, builders have contributed new “diet” parts that are cheaper, lighter, and stronger. Today an all-aluminum droid can weigh under 200lbs and be completed for about half that cost. Still, it’s the premium option.
When Make: profiled the R2 Builders Club a decade ago (see Volume 02, “R2-DIY”), an all-aluminum droid might cost $20,000 and weigh more than 300lbs. As the club has grown, builders have contributed new “diet” parts that are cheaper, lighter, and stronger. Today an all-aluminum droid can weigh under 200lbs and be completed for about half that cost. Still, it’s the premium option.
Styrene plastic
Styrene plastic is far more affordable, and it’s lightweight: A styrene droid can weigh well under 100lbs. Shared in the club forums a few years ago, Dave Everett’s styrene plans allow any builder to hand-cut flat styrene stock and build a complete droid with very simple tools, for as little as $500. The tradeoff of course is time. You need a lot of patience cutting each piece. Or spend a little more money and get CNC-cut styrene parts, as we’re doing in this build.
Styrene plastic is far more affordable, and it’s lightweight: A styrene droid can weigh well under 100lbs. Shared in the club forums a few years ago, Dave Everett’s styrene plans allow any builder to hand-cut flat styrene stock and build a complete droid with very simple tools, for as little as $500. The tradeoff of course is time. You need a lot of patience cutting each piece. Or spend a little more money and get CNC-cut styrene parts, as we’re doing in this build.
Wood
Wood is strong, light, and affordable — it’s generally used for the frame and legs and then covered with styrene. Many builders have used the Senna Wood Frame plans to build their R2.
Wood is strong, light, and affordable — it’s generally used for the frame and legs and then covered with styrene. Many builders have used the Senna Wood Frame plans to build their R2.
Choosing a Dome
R4 and R5 series astromechs have a conical head that can be made easily from flat styrene. R2-D2, however, requires a true dome that’s not easy to duplicate. In the past we would have to wait for a “run” of domes to be built by a club supplier, and that wait could be a year or more. Outside of a run, members used BBQ grills, squirrel baffles for bird feeders, and lampshades that closely matched R2’s geometry.
The good news is that today, R2 domes are readily available for club members in aluminum, cast composite materials, or vacuum-formed ABS styrene. For our build we’ll use a laser-cut vacuum-formed ABS styrene dome, but they’re all good choices. I would challenge any non-builder to be able to distinguish the domes once they’re complete.
Pre-manufactured Parts
Just as with aluminum parts, builders have stepped up to provide pre-manufactured components in cast resin, 3D-printed plastics, and CNC-cut styrene. Frank Pirz has engineered a new generation of CNC styrene components that are stronger and lighter by design. These aren’t simply Dave Everett’s plans cut out — that would be a club no-no. Frank took the club’s official R2-D2 blueprints and re-engineered all the styrene components, incorporating the club’s various findings over the years. For our droid, we’re using Frank’s frame, legs, feet, and drive designs. You can buy Frank’s parts pre-cut and ready to go or cut them yourself — just contact Frank through Astromech.net (username: mediaconvert) to get the AutoCAD drawings.
For this build, we’re using Frank’s CNC-cut parts for the entire droid body, with a combination of 3D-printed and cast-resin greebles. Let’s get started!
Now Showing: R2-3D Parts
In recent years the biggest change in building an R2 is the advent of 3D-printed parts. Amongst the builders we have a catalog of approved and verified parts that you can download and print. Before 3D printing, many of the parts on an affordable (i.e., non-aluminum) R2 were made of cast resin. A builder would get permission to copy an aluminum part, cast it in resin, and then supply it to other builders. Resin parts are still available and many builders still use them.
If you think of R2 as a large puzzle with hundreds of pieces, you’ll see why the R2 Builders Club works so hard to protect the integrity of the parts. You can go on eBay or Thingiverse and find “R2 parts” but there’s no guarantee you’ll get what you expect. R2 has hundreds of parts. If you print out a part that someone felt was good enough for their project, but it’s not to club spec, you won’t know it until you’ve wasted your money and your time. When you go to mate that part with other components it might work or it might be off enough that you’ll regret it. Do yourself a favor and follow the advice of all the builders: Stick with approved parts, even 3d-printed parts.
Andrew Radovich, aka Monkeyman, is one of the leading 3D-printed parts designers and suppliers in the club. His own R2 is completed with about 144 individual 3D-printed components. Andrew is printing everything from the Holoprojectors in the dome to the half rounds on R2’s feet. Andrew prints in ABS plastic; he started with a Solidoodle 3 but now has built several printers from scratch just to keep up with all the parts. To see what’s currently available, contact him via the club and his parts thread.
Andrew Radovich’s 3D printing Astromech laboratory. Photo courtesy of Jennifer Micheletti from Roadside Morning Glory
Half moon foot Detail being 3D printed. Photo courtesy of Jennifer Micheletti from Roadside Morning Glory
Half moon installed on R2. Photo courtesy of Jennifer Micheletti from Roadside Morning Glory
3D Printed Astromech parts waiting to ship to other R2 Builders. Photo courtesy of Jennifer Micheletti from Roadside Morning Glory
Finishing your 3D-printed parts
Prior to R2, many sci-fi robots had bolts, seams, and other crude embellishments to make them “robotic looking.” R2 is very clean-lined and smooth by contrast. 3D-printed parts can have some texture to them after the print, but you can smooth them easily enough. The acetone technique is not recommended here as you only need to smooth select surfaces. Instead, go over the part with a plastic model filler and then gently sand. Repeat until you’re happy. When you paint, use several coats of a self-filling plastic primer on the 3D-printed parts.
Prior to R2, many sci-fi robots had bolts, seams, and other crude embellishments to make them “robotic looking.” R2 is very clean-lined and smooth by contrast. 3D-printed parts can have some texture to them after the print, but you can smooth them easily enough. The acetone technique is not recommended here as you only need to smooth select surfaces. Instead, go over the part with a plastic model filler and then gently sand. Repeat until you’re happy. When you paint, use several coats of a self-filling plastic primer on the 3D-printed parts.
Building Your First R2-D2
body CONSTRUCTION
1. Cut the dome panels free
R2-D2 is defined by his unique dome, so that’s where we’ll start. Our styrene dome has two layers – inner and outer – and a base called the dome ring. The outer layer with the panels is laser-cut for us, but you’ll need to trim excess and cut the dome panels free from their retaining tabs.
ABS styrene Dome — outer layer (laser cut) and inner layer — with Dome Ring in the background.
Trim the excess off the dome.
Dome panels all separated, sanded, and marked.
TIP: Before you cut anything, label everything — many parts look similar once they’re all over the workbench. Also, use all the reference materials available on the Astromech.net wiki and forums. Read everything. Ask questions.
Mark all your parts before cutting.
2. Trim the dome support rings
The dome base needs internal support, and a pair of floral rings from your local craft store work perfectly. For now, just trim them to fit in the bottom of the dome, on top of the dome ring. You’ll glue them later.
Creative problem solving led R2 builders to use floral craft rings to strengthen the dome.
3. Cut holes for dome components
Mate the outer and inner dome and mark where you need to cut the holes for the 3 Holoprojectors. These can be stationary or servo-controlled. The front projector is what we see R2 use for the “Help me, Obi-Wan” hologram.
Mate the outer and inner dome and mark where you need to cut the holes for the 3 Holoprojectors. These can be stationary or servo-controlled. The front projector is what we see R2 use for the “Help me, Obi-Wan” hologram.
Next, cut out the holes for the Front Processor State Indicator (PSI), the Rear PSI, the Front Logic Displays, and the Rear Logic Displays.
Finally, make a cutout for the Magic Panel. This panel looks like it’s made of metal, but it lights up in some scenes and it opens in others. Because it does things that defy engineering, it has been dubbed “magic.”
Marking the inner dome for cutting.
Cut the openings for your Logic displays and test fit the logic display frames.
4. Glue the domes together
Before you can glue the outer and inner dome together, you need to drill glue holes in the inner dome as shown, so you can flow solvent between the 2 layers.
Align the domes using the top, center dimple. Starting at the top of the dome and working downward, flow Weld-On #3 between the layers, through the holes you drilled. Clamp or tape in place until dry.
Drill holes in the center section of the inner dome to flow Weld-On cement between the layers.
Before cementing the dome layers, align using the dimple in the top.
Cement your dome layers together, starting at the top.
CAUTION: Weld-On is a solvent, not a glue; it works by actually melting the plastic parts together. It’s serious stuff, so wear gloves and eye protection, use good ventilation, and don’t get it on your skin. Weld-On #3 is water thin and near instant (use a syringe type applicator), while Weld-On #16 is thick and slower acting. Sometimes to prep parts I’ll use a brush or cotton swab with Weld-On #3 before I mate a part. If you’re not comfortable using Weld-On, there are other options; the forums are filled with advice on glues and cements to use.
Aluminum domes have a similar process, as they are 2-layer as well.
Another option is a single-layer, molded fiberglass dome from MARS Props, aka Austin Roghelia and Scott Murphy. All you need to do is mount the Radar Eye, Holoprojectors, Logic Displays, and PSIs, and then paint. If you want to see a complete R2 dome being built in only 2 days, the guys have an excellent video tutorial:
The MARS composite dome. Photo Courtesy of MARS Props
5. Prep the dome bearings
The Rockler Bearing connects the dome to the body frame and lets R2’s head spin 360 degrees. Years ago the club discovered that Rockler’s 17-3/8″ Lazy Susan bearing, which is used by woodworkers, happens to be a perfect fit for R2. Unfortunately it is loaded with grease, hard to turn, and noisy. By replacing the steel ball bearings with acetal bearings and cleaning and polishing the interior channels, the Rockler works beautifully.
The Rockler Bearing connects the dome to the body frame and lets R2’s head spin 360 degrees. Years ago the club discovered that Rockler’s 17-3/8″ Lazy Susan bearing, which is used by woodworkers, happens to be a perfect fit for R2. Unfortunately it is loaded with grease, hard to turn, and noisy. By replacing the steel ball bearings with acetal bearings and cleaning and polishing the interior channels, the Rockler works beautifully.
TIP: The Rockler bearing isn’t cheap. Wait for a sale; they can be 50% off sometimes. You can also try similar-sized bearings, but the Rockler is consistent in quality, so it’s a known factor.
You’ll mount the outer ring of the Rockler bearing to R2’s Frame. The inner ring is what the Dome rests on. Drill matching holes in the Rockler, the Frame, and the Dome Ring. Do this before attaching the dome ring to the dome. When complete, the dome sits on bolts to hold it in place. Make a key mark, so you know which hole is for which mating hole on the dome ring.
When all the holes are drilled, you can now epoxy in the Dome Ring and the floral rings in the dome. Be generous with the epoxy as this will be the support for the whole dome.
6. Cut out inner dome panels
You’re eventually going to make the dome panels operable, so you need to cut the inner dome to allow for that. For the “pie panels” on top, the inner lip’s top and sides should measure about 20mm, and its bottom, where the hinge goes, about 10mm, as shown here.
You’re eventually going to make the dome panels operable, so you need to cut the inner dome to allow for that. For the “pie panels” on top, the inner lip’s top and sides should measure about 20mm, and its bottom, where the hinge goes, about 10mm, as shown here.
After cutting out all the panels and holes clean, gently sand the edges.
7. Test-mount the radar eye
R2’s Radar Eye is the focal feature of R2’s “face.” If you compare movie to movie, that Radar Eye moves around quite a bit! Almost all builders will end up placing it by eye — pun intended. If it looks good to you, that’s where it goes. I placed mine in different locations for a week before settling on what looked good to me.
R2’s Radar Eye is the focal feature of R2’s “face.” If you compare movie to movie, that Radar Eye moves around quite a bit! Almost all builders will end up placing it by eye — pun intended. If it looks good to you, that’s where it goes. I placed mine in different locations for a week before settling on what looked good to me.
If desired, make a hole now in the dome underneath the radar lens, so later you can place sensors or a camera.
Here’s where I ultimately placed my Radar Eye. Yes, eventually it gets to looking like R2!
So iconic, even with only a glimpse of the Radar Eye, you know what this picture is.
8. Build the body frame and skirt
Following Frank Pirz’s instructions the Frame and the Skirt go together fast. It’s a slot A into slot B type design. Be sure to pay attention to orientation of the parts. Use Weld-On #3 to tack parts in place and then follow up with Weld-On #16 to add strength to the joints. You can flow Weld-On #3 between joints rather easily. The frame might seem a little flimsy but the skins will hold it all together.
Following Frank Pirz’s instructions the Frame and the Skirt go together fast. It’s a slot A into slot B type design. Be sure to pay attention to orientation of the parts. Use Weld-On #3 to tack parts in place and then follow up with Weld-On #16 to add strength to the joints. You can flow Weld-On #3 between joints rather easily. The frame might seem a little flimsy but the skins will hold it all together.
Attach the skirt to the bottom of the frame. While the frame is hidden, the skirt is a visible component and will be painted later. Fill any gaps in the styrene joints with model putty or Bondo, and sand smooth.
The body has details that include the Large Data Port, Utility Arms, Data Ports, Coin Slots, Center Vents, Octagon Ports, Side Vents, Pocket Vents, and Coin Returns. Note that many of these names are not official, but rather came about because of what they seem to look like.
Mark the Frame parts before assembly. Get everyone involved, your little makers can help too.
Get everyone involved, your little makers can help too.
Ready for Frame building.
CNC styrene egg-crate Frame completed.
Skirt assembled and attached to frame.
9. Test-fit the dome
Before you attach the skin, test-mount the Rockler Bearing’s outer ring to the Frame. On the bearing’s inner ring, add upward guide bolts to match the holes in your Dome Ring and use nuts to adjust how the dome sits on the frame. You want enough of a gap to clear the frame and skins, but not too much so as to look awkward. Make sure the dome spins freely and the gap is even as it spins. R2 is coming to life!
Before you attach the skin, test-mount the Rockler Bearing’s outer ring to the Frame. On the bearing’s inner ring, add upward guide bolts to match the holes in your Dome Ring and use nuts to adjust how the dome sits on the frame. You want enough of a gap to clear the frame and skins, but not too much so as to look awkward. Make sure the dome spins freely and the gap is even as it spins. R2 is coming to life!
10. Attach the skins
Like the dome, the skins are also a 2-layer process. You can buy laser-cut skins or budget skins (scored lightly but you need to cut them out by hand), or download DIY plans to cut your own.
Like the dome, the skins are also a 2-layer process. You can buy laser-cut skins or budget skins (scored lightly but you need to cut them out by hand), or download DIY plans to cut your own.
You’ll wrap R2’s frame with the first skin layer, check the fit, adjust, and let cure, and then repeat with the second layer. If you want the body doors to open, you need to cut them out before adding the second layer.
TIP: It might seem counterintuitive, but don’t cut the doors out before gluing the skin. It’ll make the skin flimsy and much harder to position and you’ll curse the day you did it. The skins are scored, so it’s just a light touch with a knife to get the doors out.
Tack the skin in place with Weld-On #3 and follow up with Weld-On #16. Secure the skins with straps, painter’s tape, or strong magnets, and let everything fully cure before moving on.
NOTE: Some builders have had better luck with glues instead of solvents when mounting the skins. The skins are thin, and too much solvent can cause ripples that need to be fixed later.
11. Test-fit all body components
Once the skins are attached, trial-fit all your external components and adjust them if needed for final fit. For example, in the front of R2 are his two Utility Arms. If you’re going to make these arms move, they have a tendency to rub the skin as they arc outward. This can be fixed by sanding the backside of the arms at an angle. If you’re not making them movable, there’s a 3D-printed static arm and box set available in Astromech.net’s 3D file section.
Once the skins are attached, trial-fit all your external components and adjust them if needed for final fit. For example, in the front of R2 are his two Utility Arms. If you’re going to make these arms move, they have a tendency to rub the skin as they arc outward. This can be fixed by sanding the backside of the arms at an angle. If you’re not making them movable, there’s a 3D-printed static arm and box set available in Astromech.net’s 3D file section.
Don’t glue any components in place yet.
12. Build shoulders, legs, and feet
We’re building a 3-legged R2, where his center foot is extended for easy cruising. In this mode, the left and right legs are at about a 36° angle, and that angle is set by the shoulder mounting plates you used in the frame. The shoulders are round at the top and have mounting bolts for the body on one side, and for the legs on the other.
We’re building a 3-legged R2, where his center foot is extended for easy cruising. In this mode, the left and right legs are at about a 36° angle, and that angle is set by the shoulder mounting plates you used in the frame. The shoulders are round at the top and have mounting bolts for the body on one side, and for the legs on the other.
Frank’s styrene legs incorporate the ankles and are extremely strong. The legs and shoulders bear all the stress of driving R2 around. In the early movies, when they used radio-controlled R2s you can sometimes see that they had a bar welded between his feet to strengthen the legs. Today our club-designed legs are stronger and need no additional support.
Like the body, the legs go together fast. Take your time, tack in place, and follow through and make sure all the joints have a good bond. When you complete the legs, fill any gaps with a plastic filler.
Using CNC cut styrene makes for a strong design with a Slot A into Slot B type construction.
Outer leg detail with Booster covers and horseshoes.
Frame, Shoulders, Legs, and Dome ready for painting.
13. Build the drive system
R2 will be driven by two Razor scooter 100W 24V motors, one in each foot. The drive system is probably the most challenging part of the build, but with a little patience you can do this in a simple workshop. I used the tools at my local makerspace, FUBAR Labs in New Jersey, to fabricate all the components.
R2 will be driven by two Razor scooter 100W 24V motors, one in each foot. The drive system is probably the most challenging part of the build, but with a little patience you can do this in a simple workshop. I used the tools at my local makerspace, FUBAR Labs in New Jersey, to fabricate all the components.
The design calls for 2 wheels in each foot, driven by a chain. You’ll need to fabricate axles, attach the sprockets to the wheels, cut the chain to length, and assemble it all. This is a good rainy weekend project. For every part of the drive system, I made at least one spare, so if I ever need to replace a part I won’t have to start from scratch.
You can find more detail on the drive systems here.
Foot Drive parts.
Foot drives built following Frank Pirz’s design.
CAD view of the foot drive mechanicals.
14. Foot covers and battery boxes
The feet are covered with, of course, foot covers. This is where 3D printing meets styrene building. Frank’s foot shell design uses styrene for the flat sections and 3D printed half rounds for the curves under the battery boxes. Removable panels are held in place with magnets and allow access to the mechanicals in the foot. Often we think of 3D printing as a singular design choice, but in this case it’s combined with other materials to make a very practical and effective design.
The feet are covered with, of course, foot covers. This is where 3D printing meets styrene building. Frank’s foot shell design uses styrene for the flat sections and 3D printed half rounds for the curves under the battery boxes. Removable panels are held in place with magnets and allow access to the mechanicals in the foot. Often we think of 3D printing as a singular design choice, but in this case it’s combined with other materials to make a very practical and effective design.
Frank repeats this in the battery boxes. The flat components of the box are styrene, and the round sides are 3D printed. The battery box is strong and functional, with a removable rear and side panel that makes changing batteries very easy.
The motors actually extend into the battery boxes, but there’s still room for the batteries. Many builders put the batteries inside the body of R2. Instead, you’re going to use LiPo batteries, one in each battery box. Also mount the electronic motor controllers in the battery box. Then all you need to run up into the body is a low-voltage PWM signal and ground.
Foot Shells and Battery covers use 3D printing and CNC styrene parts to make an elegant and strong design.
Legs, Feet, Foot Shells, and Battery Boxes
CAD drawing of the Foot Shell.
Foot Shells and Battery Boxes combine 3D printing and CNC-cut styrene parts to make an elegant, strong design.
15. Build the center foot
The center foot and ankle are next. The center foot has a swivel caster that allows R2 to move in any direction. The center ankle attaches to the middle of the skirt. The whole setup will let R2 turn in a very tight radius. This completes all the major body components.
The center foot and ankle are next. The center foot has a swivel caster that allows R2 to move in any direction. The center ankle attaches to the middle of the skirt. The whole setup will let R2 turn in a very tight radius. This completes all the major body components.
ELECTRONICS
For our R2 we’re keeping it simple: radio control for movement, Bluetooth audio for sound, a Teeces lighting system, and Pololu motor to turn the dome.
1. Connect the drive motors
Connect your scooter motors to two Pololu 18v25 motor controllers, one in each battery box. You’re using two 11.1V 4000mAh LiPo batteries, again one in each battery box. This should give you several hours of run time. With this setup, 12 volts is plenty of power.
Connect your scooter motors to two Pololu 18v25 motor controllers, one in each battery box. You’re using two 11.1V 4000mAh LiPo batteries, again one in each battery box. This should give you several hours of run time. With this setup, 12 volts is plenty of power.
2. Mount the dome motor
For the Dome Motivator, we’re using a 30:1 metal gearmotor 37Dx52L mm from Pololu, with the same 18v25 motor controller, and a Pololu 80mm×10mm wheel with high-traction sticky tire. This wheel will ride on the inside of the Rockler bearing to move the dome, using a spring mount to maintain tension. You could go with a gear drive here, but the wheel works fine and keeps it simple.
For the Dome Motivator, we’re using a 30:1 metal gearmotor 37Dx52L mm from Pololu, with the same 18v25 motor controller, and a Pololu 80mm×10mm wheel with high-traction sticky tire. This wheel will ride on the inside of the Rockler bearing to move the dome, using a spring mount to maintain tension. You could go with a gear drive here, but the wheel works fine and keeps it simple.
3. Connect the R/C system
All 3 motor controllers can be connected to a typical R/C receiver. Drive and steering are on my right stick, and the dome control is on my left stick. If you have an R/C setup already, this is a great choice.
All 3 motor controllers can be connected to a typical R/C receiver. Drive and steering are on my right stick, and the dome control is on my left stick. If you have an R/C setup already, this is a great choice.
Since R2 can weigh in at 100+ pounds and a loose droid is never good thing around people, I suggest a 2.4GHz system with a failsafe that returns all controllers to neutral if signal is lost. You can buy these off-the-shelf at most R/C hobby suppliers.
NOTE: An alternative to a R/C setup is the ServoShock system which pairs a Sony PS3 game controller via Bluetooth (or USB) to a receiver module that has the same outputs as an R/C reciever. The ServoShock module can connect to 10 servos, has 17 digital outputs, and automatically returns to neutral if signal is lost. And it’s got the added benefit of an optional shield that plugs into Arduino; in the future you could leverage that for additional functionality. The PS3 controller works at a range of 10 to 20 meters; you’ll never be that far from R2 at an event, so range is more than adequate. A used PS3 controller is about $30 and the ServoShock module is $40, without the shield.
The optional shield has been out of stock recently, but the project is open source and I was able to order a shield PCB from OSHPark and build it myself from the documentation.
4. Build the dome electronics
R2’s dome electronics as seen in the movies include 2 big round PSI lights, front and rear logic displays, and 3 holoprojectors that light up too. The easiest way to handle all of these is with the Teeces V3 Dome Lighting System available through the club. It’s an older system, but an easy DIY kit that includes an Arduino Pro Mini to run the lights. (Soldering the Teeces kit together is what led me to seek out FUBAR Labs, become interested in the whole Maker Movement, and create soldering kits to teach others how to solder. So, I am a little partial to this kit!)
R2’s dome electronics as seen in the movies include 2 big round PSI lights, front and rear logic displays, and 3 holoprojectors that light up too. The easiest way to handle all of these is with the Teeces V3 Dome Lighting System available through the club. It’s an older system, but an easy DIY kit that includes an Arduino Pro Mini to run the lights. (Soldering the Teeces kit together is what led me to seek out FUBAR Labs, become interested in the whole Maker Movement, and create soldering kits to teach others how to solder. So, I am a little partial to this kit!)
The Teeces lighting kit, soldered up.
Once the kit is built, mount the logic lights to your logic frames. The PSI mounts are a homebrew solution from the club using 1½” PVC pipe fittings from the local home superstore.
Teeces lights in their frames, ready for mounting into the dome.
A few parts from the hardware store make a nice mount for R2’s PSIs.
Wiring up the Dome Motivator with the Pololu motor controller.
Wiring up the slip-ring connector.
Using R2’s doors to access the electronics helps avoid having to take is dome off to make adjustments.
You need to power the Dome Motivator, your R/C receiver (or ServoShock unit), and the dome lights. The ESCs from Pololu provide an option for 5V out to receiver. Add another 3,000–4000mAh, 11.1V LiPo battery for the dome motor and controller. Connect it to the ESC and use the 5V out to power your receiver. For the lights in the dome, you could put a smaller battery inside the dome, but I prefer using a slip ring to move power from inside R2’s body up to the dome. Use a 24-wire slip ring with a slip ring adapter from fellow R2 Builder, Michael Erwin. This adapter uses a DB25 connector on each end to allow you to remove the dome easily. It also pairs wires to allow up to 2 amps of power per channel to be sent through the slip ring. Again, you don’t need it now, but it will be there when you’re ready for it.
TIP: Use R2’s doors to access the electronics so you don’t have to remove his dome all the time!
Additional electronics in the dome could include servos to move the holoprojectors (you can see my holo servos here) and to open panels, or accessories like the Life Form Scanner or Periscope that rise out of R2’s dome. You have prepped your dome for these, but you’ll tackle them at a later date. (There are 6 more movies due out — you have some time!)
Holoprojectors in styrene servo mounts supplied by A&A.
A Holoprojector and PSI mounted in the dome.
Inside the completed dome.
5. Add simple Bluetooth sound
If there are 3 things that make R2-D2 R2-D2, they’re his dome, his Radar Eye, and his sounds. R2’s chirps and beeps strike a chord in people. When you start showing off your R2, you’ll be asked if R2 can make certain specific sounds. Sounds that people love. You’ll be amazed how they remember these from their childhood. Of course the club has a whole library of R2 sounds. If you want to really dive deep, pick up the book The Sounds of Star Wars by J.W. Rinzler. It covers the sound design of the movies and comes with an audio player so you can hear the sounds as you read along.
If there are 3 things that make R2-D2 R2-D2, they’re his dome, his Radar Eye, and his sounds. R2’s chirps and beeps strike a chord in people. When you start showing off your R2, you’ll be asked if R2 can make certain specific sounds. Sounds that people love. You’ll be amazed how they remember these from their childhood. Of course the club has a whole library of R2 sounds. If you want to really dive deep, pick up the book The Sounds of Star Wars by J.W. Rinzler. It covers the sound design of the movies and comes with an audio player so you can hear the sounds as you read along.
The easiest way to add sound to your R2 is with a Bluetooth speaker and your smartphone. Download a soundboard app that you like. Add your R2 sounds to it and place your speaker inside of R2. Bluetooth speakers today are very powerful — my little speaker cost around $35 and is very loud, even in a crowd. (When time and money permit, you can upgrade: now I’m using a Bluetooth receiver and local audio amp with twin 100W speakers!)
FINISHING AND ASSEMBLY
1. Test-assemble
Assemble the major components of your droid. Test all your electronics and the settings of your motor controllers. When it’s all to your liking, take it all apart again. It’s time to paint.
Assemble the major components of your droid. Test all your electronics and the settings of your motor controllers. When it’s all to your liking, take it all apart again. It’s time to paint.
2. Paint everything
First, read everything you can on R2 color selection and paint techniques. You don’t need a professional spray gun or booth — you can use ordinary spray paints for plastic, from the local home superstore or auto parts store. Choose a dry and warm, not hot, day to paint, but don’t paint in the sun, it will make the paint dry too fast.
First, read everything you can on R2 color selection and paint techniques. You don’t need a professional spray gun or booth — you can use ordinary spray paints for plastic, from the local home superstore or auto parts store. Choose a dry and warm, not hot, day to paint, but don’t paint in the sun, it will make the paint dry too fast.
Which parts should be which color? Check the reference photos in the Club’s wiki and you’ll see that R2-D2, like any character, has changed his looks over the years. While the changes may not be as dramatic as, say, 1950s Elvis and 1970s Elvis, each movie has some differences. For example, in the original Star Wars film (Episode IV: A New Hope) R2-D2’s holoprojectors have a black ring around the edge, while in other episodes they’re all silver. The R2 we know from the original trilogy looks different in the “prequels” (and even more different in the Clone Wars animated series). There are dozens of details that change like this. Paint R2 to the scheme you’re happy with. Some builders mix it up. It is all your choice. I’ve never had a kid run up to R2, throw his arms around him, and say, “R2, your holoprojector is the wrong color.”
For white parts I went with a flat white and for R2’s signature “blurple” color (aka “Hypo Blue”), I alternated between metallic blue and gloss purple. While the blue coat was wet, I sprayed a quick dusting coat of purple. For the “aluminum”-colored parts I used Eastwood “Almost Chrome” spray paint. Do your research and test your colors. Some builders like to clear coat; I do not. Other builders have taken their R2 to the local automotive body shop to be painted; that works too.
For R2’s shoulder joints, instead of paint I used aluminum tape. The tape has a sharp, bright look that works with the other aluminum colors to make R2’s appearance pop.
The 4 battery cables (Foot Hoses) are made from braided faucet hoses I found in my local home improvement store. I used BrassCraft’s polymer braided flexible water supply hoses. I started with two 30″ hoses, cut them into 4 pieces, painted with bronze craft paint, and glued them into knurled resin knobs. You can use stainless steel braided hoses, but they’re more expensive and harder to cut.
The 4 battery cables (Foot Hoses) are made from braided faucet hoses I found in my local home improvement store. I used BrassCraft’s polymer braided flexible water supply hoses. I started with two 30″ hoses, cut them into 4 pieces, painted with bronze craft paint, and glued them into knurled resin knobs. You can use stainless steel braided hoses, but they’re more expensive and harder to cut.
The last detailing choice is weathering. I hate this conversation because I still cannot decide — I love the weathered R2s, but I want the pristine, ready-for-the-big-ceremony R2. Except, then there are times I want a weathered, just-back-from-battle R2. I might need to build a second droid.
You might be wondering how builders get the dome, which is painted, to look even more like milled aluminum. You want Rub and Buff, a wax paste with metal in it. You can find it at your local craft shop. A little dab can do a whole dome. It’s like a shoe polish. Once you use it though, you cannot paint over it. I opted not to use it yet. But you can add it anytime. Just search YouTube for techniques to apply it. It takes a lot of elbow grease, but it’s worth it.
Painting tips
- Prep all your parts. Make sure you clean them of any grease or mold release, sand them smooth if needed, and remove all dust. Your spray paint will only look as good as your preparation.
- No matter how you paint, use a top quality painter’s masking tape. It makes the difference.
- Primer is a good idea. It may not be strictly necessary for say, white Krylon on white styrene. But many metallic paints are paired with a special primer you should apply first, to reflect more light through the paint coat. And on 3D-printed parts, use several coats of a self-filling plastic primer to smooth the texture.
- Paint in several light coats — don’t try to paint it all at once.
- Make sure you use paints of the same chemical family. Most problems occur when builders mix enamel with acrylics without realizing it. Let everything cure as directed and don’t rush.
Dome and parts ready for painting.
Prime first, then paint. “Almost Chrome” paint for all the “aluminum” parts.
“Blurple” is made by alternating Metallic Blue and Metallic Purple.
More painting
Close-up of painted parts
3. Assemble your fully operational droid!
After all the paint is dry, you can begin final assembly of R2. Welcome to the fleet! You have joined an elite few who have a showable, operational droid. We have thousands of members, but there are less than 500 operational droids, and less than 200 screen-showable droids worldwide.
After all the paint is dry, you can begin final assembly of R2. Welcome to the fleet! You have joined an elite few who have a showable, operational droid. We have thousands of members, but there are less than 500 operational droids, and less than 200 screen-showable droids worldwide.
With his signature dome and radar eye, R2 is recognizable anywhere, in any stage of completion.
Dome completed
Painting is complete, R2 is almost ready for Maker Faire.
Conclusion
That wasn’t bad at all, was it?! What do most builders do when they complete their droid? Start a second one. In the meantime there’s plenty of opportunity to show off your R2 at Maker Faire, attend charity events with the 501st Legion, take him to libraries, and brighten up people’s day. You’ll inspire other makers, and maybe make some new Makers too.
In an art-imitating-life scenario, the club has gone from building movie replicas to being the source the moviemakers go to. R2 Builders Club droids are almost always the ones you’ll see in TV commercials and promotional videos. During the filming of Star Wars movies, club members have worked as consultants and supplied droid parts. (If you want to know who they are, you’ll just have to join us in the Astromech forums.)
If you take anything away from this article, take to heart that you too can build an astromech droid. The club is here to guide you. Of course there are many more details you need to complete your R2, but I hope this article helps you along your way.
How long will it take? My droid took me over 3½ years, with breaks in between. Other builders have done it in less than 6 months. The average is 1 to 3 years, but it’s up to you. It should be fun, and if it isn’t, then step back for a while. You’ll get there. I hope to see you on the forums and at the next club event.
R2 Builders at the Tokyo Maker Faire
Partying with the DJ at World Maker Faire in New York.
With New York’s Finest at World Maker Faire in New York
Entertaining the Crowds at World Maker Faire
East Coast R2 Builders at World MAker Faire 2015
R2 helping out with the Soldering Sunday “Make with Us” workshops in the Maker Shed
R2 at the Barnes And Noble Maker Faire
R2 at The Barnes and Noble Maker Faire with members of the 501st Legion.
Never Leave a Jawa alone with a droid – even at Maker Faire.
Left to Right, R2 builder Paul Gentile, R5-J2 Builder Dave Castellano, R2 builder Kevin Abato
Web Links and Additional Resources:
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