I've been collecting more parts and now have everything I need to try and get this CPU arm working. I bought a Fergelli L-16 actuator which is the medium length model with a 100 MM stroke.
First I unscrewed the end plug.
Next I bought an 8MM metric stud with a 1.25p and cut it to length so the CPU arm would screw on it.
I tapped the CPU tip to 8 MM and then cut the stud to the correct size and tried a few tests with 12 volt power and everything seems to work perfectly.
The tube came with this plastic plug. So I filed it down until the L-16 would fit inside of it.
I cut that mount off the rear because I need to recover that space. You gotta be careful not to cut off the wires.
With everything installed and the rear plug installed. I still need about 1/4 of space to get the plug to fit inside. So its off to the bandsaw.
I screwed in a 1/4 -20 rod and pushed it to cut off what I'll use later as a shim. DO NOT try something like this by hand. Trust me you'll need your fingers to operate a droid.
I'm almost a straight cut, but a little crooked. I filed down a square hole in the left over 1/4 inch piece of round aluminum.
That shim then goes over the actuator and holds the rear end of it centered and then the rear aluminum plug fits. So its time to test it out!
FAIL!
The tip came out as it has during all the tests and snapped off and fell into the cat's water dish:(
I was so close and ready to install it and the L-16 you've failed me. So its time to take the L-16 apart and see if I can fix it.
Here is the inside of the L-16. It has a screw drive that has a high pitch. One you can't fabricate parts for with a metric tape and dye set. The motor and everything works just fine. What happened is a piece of plastic broke off from the square limit switch.
This is a closeup of what I believe is the limit switch. There used to be a small tube of plastic that threaded to in the inner part to this screw shaft and its outer part was 8mm. So it was very thin and the weakest link in the system. Somehow I need to fabricate this square part seen and its tube part out of aluminum. Otherwise this L-16 is of no use.
So the moral of the story is don't follow in my footsteps if you were considering this route. After about 8 tries the L-16 failed and rendered itself to the junk pile. Now I'm not sure how to proceed. If I can find a tap set to duplicate this pitch I might just JB weld a small tube over this square piece. I'll try a few things before this hits the junk pile.
One day I will get this to work and save people from getting crushed in the trash compactor.
The first thing I need to do is to trim off the excess around both sides of the head where the vacuum molding has left over. On the back of the head I'm unclear how much material to remove so far. It looks like I need to trim off about 7/8 of a inch and will ask the 3P0 builders about that.
The front of the head is more straight forward on what needs to be cut out. But I'll wait a day or two until I'm clear on this.
I asked the C-3P0 builders how I should proceed and was told to slowly trim away the extra material. So I cut it off and still have a little more to trim or file off later.
Then I cut out the mouth and used a pencil to mark where I need to cut out the eyes. This is a bit nerve racking to do with a razor blade. 1 wrong cut and you will nearly ruin the part.
These are the tools I used to work on the head. A pencil, razar blade, snips and a curved file. So now the eyes are roughly cut out. You'll need to very carefully widen the eye holes until the eye ring thingy just barely fits in with a bit of force. You don't want it sloppy, nor do you want to over cut the eye holes out of whack so its not a perfect circle.
Now both eye rings fit into place and its started to really look cool like the actual droid! Also it don't hurt to put some blue tape around the areas you plan to cut incase you slip or get carried away filing and hit parts of the face on accident.
I've been slowing down my work on props lately and collecting parts. When I'm not working on my astromech droids I'm collecting parts or planning out how I'm going to do my next two robots. There is still much to do with R5-D4 like put servos and other things in the dome. I won't touch that dome until I have my R2-D2 or R2-Q5 finished. It took me 40 years of my life without a finished droid and I want to keep one on hand at all times. When I finish 2 of them. I'll take R5 apart and upgrade that.
My next project I'm collecting parts for is a full size C-3P0 that will be a wearable costume and also animatronic from the waist up. I got the head parts today and it was a great deal for really well made parts! I'm quite happy with the bang for the buck here. The builder is very good with vacuum formed props.
It also includes the rest of the head detail pieces including transparent lenses and LED lights, resistor and everything you need. You have to trim and sand and do your share of the work to get the head ready for the chrome plated look.
I also ordered some feet. These feet need to be trimmed and then you can wear them over a size 10.5 narrow shoe. Which sucks my feet are 12-13:( I have no idea what the part next to the feet is for. I saw my first real life 3P0 at Phoenix Comicon and that pretty much cemented my on/off decision to do a project like this. This robot is frakking cool!
I could have bought a complete 3P0 off ebay from some recasters painted and done for half the price of going this route. I'm not that type of nerd and will only do business with decent folk that work sometimes with LFL that offer parts, not completed robots. A good deal of the fun is putting some elbow work into these projects. Another reason is learning of new skills you didn't know when you started this stuff. By the time you finish a droid or large scale robot. You'll probably be pretty good at painting, polishing, a dremel master of all things, soldering and medium level electronics, familiar with LEDs and china, and how CNC machine basics work. You'll end up knowing enough about nuts and bolt sizes to get hired at Ace Hardware if you don't the guys in the store on a first name basis.
That's valuable experience you'll never get if you hit 'buy it now' on ebay for a finished robot. There will be times your robot will break and you say. 'No big deal I built it once its easier to fix that part the second time. People who buy a finished droid have no idea what kind of electronics are inside, where parts came from, part terminology of what's what.
Anyway, when I'm not working on droids I have this evil Terminator T-800 robot I'm working on. This is the first of many skulls. I'm going to later replace with this a chromed out fullsize head. This head won't be on the finished Terminator but I needed a Terminator fix so I bought this to piece to place around with until I can afford a 1:1 head like this head in the photo below.
Eventually I'll buy the head for a small fortune. That will most likely be the only part on this build that I buy. The rest I'll build from scratch as you really can't get in on T-800 part runs as there aren't any. I think I'll finish the C-3P0 first and servo up that droid to figure out how I'm going to to this moving T-800 robot. This will be my masterpiece of a robot out of all of them.
I also got two of the most powerful Hitec servos servocity.com has to offer. This will beef up the power to move the Gripper arm and CPU arm up and down. The servos I have installed are 133 oz of torque. The new servos above are rated at 403 oz of torque. Each servo is so expensive it cost more than the 3P0 above and the Terminator head also. By the time they arrived I checked servocity and they had just published newer more powerful servos making mine obsolete by the time it arrived:(
Two of best servos they offer cost about as much as an Xbox 360! Ouch! I'll need tons of those to animate 3P0 probably enough to pay for a small used car.
It was 118 degrees outside so I just stayed in doors and worked on my droids gripper arm.
My L16 Linear Actuator came in and I had planned on using it in my CPU arm. In the photo its positioned where it should be in the tube. As you can see the L16 is about 1 inch too long. Sure I could cut out the breadpans to accommodate.
However I noticed it seems to be about the right length for the gripper arm's tube.
The L16 fits inside Tom D. Waterset gripper tube like a glove. This is a pretty good pairing up. Even the hole around the black nylon tip is the exact size! The next step was to use the existing hole you see and drill it wider. Then tap it for a 1/4-20 thread.
The thin aluminum I just tapped isn't going to be enough to maneuver this later with a servo. So I took a low profile 1/4-20 nut and sanded it down so I could slip it in between the tube and the L16 .
Hopefully this is going to be strong enough to muscle the arm up and down hundreds of times without failing.
This is going to be very tricky to pull this off. It has to be screwed in just the right amount. If you go too far you start eating into the plastic of the L16.
Upon further tweaking of this build. I decided I had to push the L16 further into the tube and remove more aluminum material I marked with black. I used a dremel to cut remove the material.
Then I marked a squarish area I'll need to file away until the front of the L16 can slip through it.
Now it sits flush when its fully retracted. Otherwise you don't want it to go inside the tube and snap off the gripper.
I cut this small tube off to act as a shim to make a tighter fit for the gripper to attach to. Its not my idea method, I'd rather drill and tap something but I'm not in the mood to take the L16 apart yet.
Now its ready for some test fits in the breadpan. This next tass is going to be difficult to do when you mount these for your first time. You have to make sure it don't hit the skins when it goes up and down on its right. At the same time on the left you have to make sure on the other side it don't hit the hinge on the door. Which is usually fine when the door is open. When it closes check to make sure the hinge don't hit the tube and closes properly. So you gotta find the sweat spot in the middle of that and have your hole on the breadpan drilled in just the right spot to clear the left, right and up and down or this arm won't work right.
I added a short threaded rod during test fitting that I'll use to mark where I'll need to drill a hole in the breadpan. Since I pushed the L16 into the tube deeper the end of the tube is hitting the back of the breadpan. So I marked the area I need to remove and its off to the Dremel. Its pretty hot outside cutting this stuff. So far we broke a ten year record of 116 to 118 outside! Ouch.
Now its shorter and ready to install. I'm not sure if this would fit inside without removing some of the back it barely fits in after I shortened it.
This is how I mounted the gripper arm in my breadpan with the servo. Now its time to install it and hope it works. Without the gripper on the tube worked electronically clearing where it needed to.
In this photo I'm using a tube to hold up the arm. The reason is I have to take the photo and can't operate the transmitter at the same time. The other reason is it didn't work:(
It took 6 hours of work to get to this spot. The bottom line is the servo couldn't handle the weight. I had to remove the gripper and now it barely works rising up. I don't know why it worked fine in the tests before this. So this is version 1.0 of my development of getting the gripper to work.
The next phase will involve upgrading the servo to something more heavy duty. I might also take apart the L16 and change how it attaches to the gripper. The ultimate thing is to have the gripper open and close. I have a couple of ideas on how to do that. I need to do that because as you can see in the video. The door won't close unless the gripper claw is also closed. Its very tight in the box but over all I'm happy I have gotten this far in my astromech build.
I'm going to order a shorter version of the L16. This one is servo operated instead of using a Styrene 10 motor controller for it like I'm using now. That comes with an advantage of being able to limit its travel via coding. Another thing is I can shove it further into the tube and have more meat for the servo to screw into the tube so its not so flimsy. I might get a slight thicker tube and start over. Its basically a simple aluminum tube with a nylon plug is all.
I haven't updated here in a while but I've been busy with some parts and waiting for things in the mail.
I'm pretty much done painting the CPU arm and I have the servo attached! Painting the arm was much easier than I thought. Here's some of the basics so you can get an idea on how to paint yours.
I masked up the tube and painted it black. I didn't use any primer on these parts. I don't know why, I just didn't.
You do the same with the tip. Cover up everything with blue tape that you don't want paint on. This section I'm painting anodized blue, same can I'm using for R2 blue on the droid. Clearly some areas will have over spray. Take a Q-tip and Acetone and clean that off. If you happen to mess something up or don't like how it turns out. You can just wipe the paint off with a rag and Acetone, its nearly an idiot proof.
I painted 2 sections a day until I had the tip done. It took about a week or so to get it how I liked it.
It turned out pretty cool. I might add a few more color details to the arm. I tried to but couldn't get the paint how I wanted it. Eventually I want to add the wall section that this tip plugs into.
My idea of putting threads on this servo rod also worked in my favor. I hooked it up to my droid and tested it out. The servo is able to move the tube around, so far. However when doing that I realized this particular servo isn't going to work. Its a default clockwise servo. I need a counter clockwise servo so it move up. I might as well buy one with more torque while I"m at it. This servo will end up moving the gripper up and down.
Yesterday we had a local R2 build day. We focused on R4 domes this time. Droid Welder has a styrene R4 dome from a small limited run years back. So we copied that or he did for several builders in town. It will take 2-3 people to bend one of these and hold it and glue it together. I think before I try that I'll copy this onto some sheet metal and bend that up and see what happens.
As if I didn't have my hands full already. My other JEDI control kit for R2-Q5 is here and ready to activate that droid. I haven't really thought out where and how this will go in that droid yet. I'll need to let that simmer for a bit.
My droid hasn't worked for a while because I'm upgrading some electronics. Here I have one of Dan's power distribution boards mounted to an aluminum plate I painted blue. It powers the JEDI control and what you see on the other side.
This is the other side. It has four Syren 10a Motor Drivers on it. They power the dome motor, CPU actuator, Gripper actuator and dome lifter. I don't have all that stuff quite yet, but when I do I have the electronics to power it already installed inside the droid. All you have to do is plug in the red and black wire to each Syren 10A and its ready to go and control with the VEX transmitter.
Upgrade complete! Power is restored back to the droid via the power board. I also installed a new Pittman motor so the dome is spinning again.
I also installed the new amp on the back side of my electronics panel. Its not quite loud enough, not as loud as the previous amp. I wonder if there is something else I can do?
