E4-b4 Build Diary. (r2-d2's Little Brother)



Your more than welcome with me sharing this build, and I'm pleased you're enjoying the build diary. Yes, beer and building robots don't mix, but it sure does help... sometimes, lol. Thanks for the kind words. I'm pleased how it's coming along, but a little disappointed I had to leave the retractable leg out this time.

Oh and BTW, you gotta love them EZ-bits, don't you? I had these grippers knocking around for a while so I thought I'd put them to good use. Smile


Are you using plans from the astromech builders club? I got all the plans and half scaled them for a mini build I was going to do. I believe I started a project showcase on it, but I can't be sure.



I'm not really using plans as such, as I figured I'd challenge myself and do the build with little reference. I do check some photos from time to time, and the measurements I found online, although I'm not sure what the source was.

By the way, it's good to see you on the forum again. I haven't seen you around much. I hope you're keeping well. Smile


Nice progress Steve. It's coming together nicely. It's amazing what a little paint and some hardware will do to help being the build forward.

I was sad when you decided to ditch the retractable leg. It would have been so cool but I understand why it had to go. Somethings just don't fit and work the way the brain invasions it. The way my mind works is after I had made up that list you came up with and saw all the negatives and only two positives I would have spent a year working to overcome the downfalls. Then after all that I'd end up scrapping it anyway because I found a better mousetrap. *tired* I'm actually at that point with my B9 build. I'm considering scrapping a big part of my sound system to make room for a better power plant. So my hat's off to you my friend for being able to make the hard decision when it needed to be made. Winky

Ya, I agree. You'll need smaller speakers. Tongue



Yeah I don't need to make legs. Just throw some motors in the speaker boxes, lol. Tongue

Seriously though, I say I had a few beers and had a good think about the retractable leg, but the truth of the matter was I put the build on hold for nearly three days to decide which way I should go. Better materials, better planning, and a much better bank ballance, and I would have persevered with it as I really would like to have done it. *stress* *stress*

Wow, that's a big change fo B9. That's quite a sound system you have there, but again, the pros and cons for a better power system... I would probably do the same if it's any consolation.

Anyway thanks for everything you said. It was very nice to read. Winky


wow your build is looking incredible! Im sorry about the third leg but the astromech will still turn out great. I often find myself rethinking and having to change the design on the go... Its a hard thing to do but I think in the long run you will be happy knowing you did what you wanted Smile



Thanks buddy. Yeah I think you're right about the decision. I'd rather be happy and have something reliable than have to keep adjusting and worrying about if things are going to work correctly. Anyway, the extra space will give me room to add a few goddies, so it'll be worth it.

Starting on the outer legs tomorrow, so that'll keep me busy for a while.


Day 42
(14th September 2015)

E4-B4 is now standing in his own two feet...

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E4-B4's status has been changed (or rather, been demoted) from Project to [i]Prototype[/]. Someone said to me "it will be a rewarding but challenging build", and boy they weren't kidding when they said challenging, lol.

As I mentioned previously, I had to leave out the retractable centre leg for a couple of reasons, and after a lot of trial and error, I'm now leaving out the motorised shoulders for when he lays back in three leg mode. This was because the overall weight of the wooden body was just to heavy for the (quite powerful) motors/gearbox to reliably work. So I have now removed the centre leg completely, and removed the shoulder motors and fixed the outer legs in place. This I was not happy about as I have now lost two main features, so I will continue the build as a prototype as he is already partially built and use him for script testing and experimenting, then sometime next year I will use strong but much lighter materials to do the build I originally wanted to with all of the movements I wanted him to have.

So, on with the update.

Using some MDF sheet and a mix of 2x2 and 2x1 batons, I measured and cut the necessary lengths and shapes for the outer legs.

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Originally, I had fitted two motors and bearings which I attached to the body.

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But with the decision made to have the legs static, I removed the bearings and motors, cut some new round spacers and attached the legs to the body. I then traced all of the necessary wiring for servos, drive motors, lighting, and ping sensors.

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The next step was the two feet. Again , the frame work for the feet were cut from MDF and 2x2 batons. The motor/gearbox assembly were fitted along with rotating caster wheels. Some holes were drilled in the foot skirts to house ping sensors, and under foot lighting was added.

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I had an absolute nightmare getting this guy to drive in a straight line. Measurements on a robot build, any robot build, is important as many of you will attest to, but on a build like this, they really do have to be spot on. But even with pretty much spot on measurements, with the main drive wheels in his feet, I tried adding and removing caster wheels, adjusting the caster heights, raising and lowering the overall height of the legs, and tried in different floor surfaces, and he either pulled to the right or to the left (mostly to the left)

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But after two full days of adjusting, trial and error, and dialling in, I'm pleased to say that I've got E4 pretty much tracking straight and true. Nothing special, but here's a short video demo of his first successful drive test...

Each foot now has the drive wheel and one rotating caster fitted to the back of the foot. What I will do for his movement will be to add ramping scripts the forward, reverse, and turning for more elegant movements and to reduce the risk of tipping over, and add turning scripts for the U turn style movement that R2-D2 does in the movies.

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But in regards to the build, the next thing I will do will be to give him some new shoes (basically covering them up) and add the battery boxes. Then it's on to... the head, and that takes me over half way of the build process.

Fun Query:

After now losing the two main features I wanted, I watched Star Wars ep4 to give me some motivation to carry on. So, with all of the military hardware the Empire has, a humongous heavily armoured battle station, massive star destroyers, artificiality intelligent robots, powerful weapons, the power of the dark side of the force, and rely heavily on troops, you would think that the empire would splash out a little bit more on better armoured suits for the storm troopers. I mean, one shot from a laser blaster... and they're toast, lol!


You may have given up some options that you liked but what you presently have is REALLY GREAT !


Thanks Doc. That's very nice of you to say. It's words like that which will push me through my disappointment of leaving options out for now, and carry on making him the best I can. Smile