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

 
#11

Day 7
(11th August 2015)

Well, I managed to get a bit further into the build over the past couple of days, and the base is pretty much done. So here is what I've completed so far.

User-inserted image

First off, I concentrated on the centre foot. I put the framework in for the foot to add weight and will act as supports for the foot side panels. I then added two stabilisers to the top of the foot to reduce side to side pivot play and keep the leg straight. Then I added the front and rear panels.

User-inserted image

User-inserted image

I've also started on the first part of the electronics. Actually, all I've actually done was to trace some wire which I will be using later.

User-inserted image

Carrying on with the electrical theme, I have now cut and attached the lower foot skirts, with the front skirt panel housing one of 6 ping sensors that will be installed in E4.

User-inserted image

User-inserted image

User-inserted image

I added a few dabs of silicone and traced the wires to the front of the leg.

User-inserted image

User-inserted image

To finish off the main build of the front foot, I added the two top and side panels along with some detailing. The foot is now pretty much ready for paint and a few final details.

User-inserted image

User-inserted image

The next job was to cut an upper base panel and attach it to the body frame. This will support the foot mechanism.

User-inserted image

User-inserted image

For the start of the body skirt, I cut out twelve 2" triangles to support the skirt skin which I will attach later.

User-inserted image

So that brings this update to a close. I've changed the idea of the "gear" system to raise and lower the centre foot, and instead decided to go for a pulley system with a servo interlock. This should be less strain on the motor, and I'm not 100% convinced that the gear assembly idea will work very well. Once the foot is painted, I will fix it to the body and look at fitting the motor when it arrives.

User-inserted image

That's all for now. Smile

#12

loving your build and am following it avidly. I just have a thought on the ping in the foot, read somewhere that ping sensors don't like being too close to the floor because they can sometimes read the floor as an object. so give it a test to see if it's ok.

#13

@bborastero.

Thanks for your comment. So far things seem to be going well and I'm enjoying this build so far and I'm glad you are enjoying the diary.

Also, thanks for the tip on the ping sensor. Bearing in mind that I'm sill yet to fit the caster wheel which will raise the ping up a bit from what's currently shown in the pictures, I will take your advise and test it to see if there are adverse effects. I can always relocate it higher up on the foot which will be an easy fix and will blend in with the final detailing. Smile

#14

What "scale" is this build, approximately?

#15

@Zap.

I'm going by some full size 1/1 prop build plans I found online a while ago, minus 2 inches here and there. The reason for the slight size change is the dome is normally referenced at about 18" diameter, and I have one at 16", so he won't be much smaller than a full size prob build.

#16

Ok, that's cool. I was going to point you at some half scale 3D printed astromech detail parts but I think your build is too big for that.

#17

@Zap.

Ahh, that would have been cool, but like you say, they would be a bit small. No worries though as its a custom build and not a replica to give him some individuality. Thanks anyway though. I appreciate the thought. Smile

#18

Day 9
(13th August 2015)

So it's time to get this centre foot fitted and move on to the next stage of the build. I've been delayed a bit waiting for the motors to turn up which seems to be taking an age to get here, but I'm a little step further along (no pun intended). Tongue

So with the centre foot pretty much finished, it was time to get some primer and some paint on to it.

User-inserted image

User-inserted image

While the paint was drying, I fitted the runners, which are cupboard draw runners, which will guide the foot when it lowers and raises.

User-inserted image

I attached the runners to the leg and gave it a "drop and raise" test, and all was well, with plenty of space all around the recess when retracted, and all that needs doing now is to fit the motor.

User-inserted image

User-inserted image

Last job I did was to fit 2 further draw runners that will deploy and retract some utilities to be fitted later. I've also drilled some holes to feed some head/microphone and charging cables through for the Acer tablet.

User-inserted image

All that is left to do on the centre foot is to add some final detailing and caster wheel which will be done towards the end of the build. When the motors and 15 amp motor controllers turn up, I will make a start on the outer legs and feet. Well, it's starting to take shape (sort of), and I'm looking forward to getting them outer legs fitted.

User-inserted image

Until next time. Winky

#19

Day 19
(23rd August 2015)

An update with a bit of a difference where a design decision had to be made. More on that in a bit. First off, a BIG thanks to @Zap Brannigan and to @Robot56 for their advice and answers given in Robot56's thread, which were a great help.

So, I had a couple of extra jobs to do on the centre foot which was to fit two free steering casters, and two LED strips for some under foot lighting. I added some aluminium tape to the underside of the foot to reflect and disperse the light.

User-inserted image

User-inserted image

So, the big decision I mentioned was in regards to the build design of E4 while I was finishing off the centre leg/foot assembly. I temporarily fitted a motor to the leg to try the mechanism out, and it did work but I just didn't fully trust the set up to work flawlessly every time. So I sat back, had a beer or five, and went through the pros and cons of having a retractable centre foot, or having it fixed.

The pros for having it retractable were...

1.) Not many Astromech droid builds have a retractable third leg, so having one would be something different.

2.) It would quite simply be a cool thing to have.


The pros for having it fixed down were...

1.) The mechanism was taking up a lot of room (almost half the build), so without it gives me more room for other things I wanted to add.

2.) Loosing the assembly would make the whole thing a lot lighter.

3.) It would give greater stability when driving around in upright mode (two leg mode although this would technically be three legs).

4.) It will still have the ability to lean back in to tripod mode.

5.) No chance of retractable leg interlock failure, which could potentially end up having E4 fall flat on his face... Ouch.

6.) One less motor and motor controller to use which is better for power management (better run times).

7.) Less structural strain on the outer legs and body frame when in two leg mode, again due to excess weight.

And 8.) I just was not confident enough about the interlock and the amount of weight the motor had to lift. Too much could go wrong which could have led to bad things happening.

So the decision has been made, and E4-B4 now has his centre leg permanently fixed in the down position. I may revisit this one day, but for now I have fitted two cross sections to the underneath of the body, and two supports on the lower tier section where the leg is now permanent fixed.

User-inserted image

As mentioned in point 1 for having the leg fixed, this has now given me more room to work with, so I have slightly relocated the existing utility runners that I fitted on the lower tier, and added two further runners above them. The servos are securely fitted, and linkages I made are connected to all four runners.

User-inserted image

User-inserted image

User-inserted image

User-inserted image

I have also cut out some recesses on the lower and upper tiers where the tablet will be housed, with some brackets to hold it in place.

User-inserted image

I though I'd have a laugh at this point, and placed the dome on to the body frame.

User-inserted image

Looks nothing like an Astromech droid, lol, and looks a long way off from doing so. But at least it has a bit more of a structure now, and at this point, I'm probably about half way through the build (excluding electronics). He also looks a bit taller than I thought he would be, but the measurements are correct, so it's all good.

I then started Work on the upper tier where I cut and fitted four 2x2 supports for the outer leg brackets, which I will be working on next. I also added a long utility runner with a servo, two further non servo powered runners towards the centre of the platform, and a lever mechanism for a manipulator arm. The two non servo powered runners now supports a retractable electronics platform, which I will be able to manually slide in and out for easy maintenance. I added a little bit of colour to upper tier which is now fixed to the frame and waiting for the outer legs to be made and fitted.

User-inserted image

User-inserted image

Finally, I added some more gold and burgundy colouring to the rest of the body which makes the whole thing look a bit tidier (kind of has an IronMan look about it, which was unintentional, but kinda cool). Now it's starting to look like something other than a load of pieces wood fitted together. I still have a few more supports to cover and I'm going to respray the foot and leg with a darker, glossier blue which will better match the HIPS sheet skins.

User-inserted image

User-inserted image

In the next update, the outer legs should be done, and that's a point I'm excited about because that will take me over half way through the building phase, and should start to look more like a droid, hopefully.

User-inserted image

(I think I will have to find some smaller speakers for him though *eyeroll*)

More soon. Winky

#20

@SteveG Thanks big time for sharing the build with us. It is fun to sit back and have a Beer or 6 and watch someone else's project come together.
I really looks great. I have to laugh, you use the EZ Bits to get things done easily, like I do.. (Gripper etc.)

I look forward to seeing your future posts.

Ron R