Scratch Build – In Progress Project: Tachikoma - Wiimote Controller Test

I have found an assistant to help me with the details!! Courtesy of EBay





This is what happened to my test mold. I didn’t reinforce it properly on the back with cotton and it brooked a little. No problem since it was a test, but this shows the importance of a proper reinforcement of the mold.



I have been working on the molds. Six done, two on process. 5 more to go.













I am happy with the results of the molds. The normal mode to do mold for fiberglass is to make them of fiberglass, but if you don’t do them perfect at the first time, they are very difficult to fix after. I made my CAD drawings trying to maintain a draft angle of a minimum of 3 degrees, but it is difficult to assure with of all sanding and filling.
There are some minor fault with that I can fix sanding a little the molds, which would be very difficult to do in fiberglass molds.

 

Nice work

 

Fist I want to apologize for so long time without updating the log. Lot of things to to, lot of work, family, etc. Little time and lot of things to do.
I have started again to work hard on this mod. I found time and I have done a lot of advance in last month.
First, a picture of actual status. Tachikoma is coming!!!!!!



One year ago, I was making plaster molds. When I restarted to work on them, I found the plaster molds with a lot of cracks an pits, nearly useless. I was told that I should have sealed them with primer berore storage them. So they have a sand end, at least I use them for let my frustations out...



I decided to go for fiberglass molds. I decided to have better finish of the surface of the plugs to have better molds finishing to have minimun sanding of fiberglass. (At the end I have to sand anyway, I am really tired of sanding. If you ever decide to build something on fiberglass, be ready to do lot of sanding)

I cover the plugs with layer sof gel-coat. Is similar to polyester resin, with the same calayst. After cure, I sanded all the plugs, what took ages.







Another recomendation: My first plan was to build the plugs as two parts, one for every part of the mold, and join it after. But after some trials it is likey I would have some bumps on the joint, so I joint the plugs halves together to have better finishing on the joint, like a replica of the final part.
After that, when I was more or less happy with the plugs, I cover with an epoxy primer.



To build the molds like this way, you need to divide the plugs in two halves. Fist cover the half not to be molded.





The half is marked by hand.

To build the flange, I used a flexible joint, like the ones used to seal the windows.



To finish the flange, I covered it with plastic tape.



Once you have the flange, comes the fun part with fiberglass.

First waxed the plug, by hand, 3 times.

Two layers of PVA, blushed.

Two layers of gel coat, brushed.

Two layesr of fiberglass mat, 300 gr m2.

ANd 24 h later can be pulled out of the mold.

Most of my plugs were destroyed with the process of pulling out the mold. Basically the foam, cardboard structure didnt have the strength to resit the stress of demolding. If some one have the idea of building something similar, I strongly recomend him to build the plug with some fiberglass to have the strength to resit the demolding process.

More to come later.

 

pretty cool i havent seen a project log here before that didnt involve a pc in some way !!!! pretty cool and very original in a way

 

that's HUUUUUUUGE.

 

One leg and knee spans a whole workmate work bench? Not huge - enormous. This is neat!
John

 

It's good to see you back at it.
-and It's HUGE! #3

 

Man this is huge!, you could fit like 2 computers in tn this!

 

Yes, its huge. Mainly because the two automotive batteries of 75 amp hour I am planning to include. I want as much autonomy as I could.

This is a part after pulling it off the mold



It has some extra fiberglass I cut with the dremel.



The two parts of a leg, prepraring to be joined.





I used fiberglass tape to join the two halves. After it cured, I cut the extra fiber and fixed imperfections with bondo.



The same with the arms.



The cannon



And the connector between the head and the backpack



For the head, I molded three eyes, and cut a hole in the head and inserted them.
I reinforce the inside with fiberglass and filled outside imperfections with bondo.





Some preasembly without the frame.






More latter.

 

For the ones that asked how big this is, here is a photo of my Tachi with my niece. She is one meter tall...




And If you thought there wasnt any pc involved on this



a VIA EPIA EN12000EG.

 

omg! That thing is huge!
very nice work thought, keep it up

 

Hey....

....You wanna see something cool?

http://www.youtube.com/watch?v=mL4dOm5t9Bs&feature=related

http://www.youtube.com/watch?v=p1xwF6y8MOs

 

damn i missed this project, but it shows a hell lot of backyard moldmakin techniques. really good work.

 

This is the craziest mod I've ever seen

 

Ok, that is cool and insane.

 

Ok I pretty much joined to say this is an awesome creation!

Tachikomas are the best.

 

very nice and great good job

 

Thanks all for your support. I hope you all would be surprise with the result.
While I was finishing the plug for the backpack, I switched to work with the support frame.

Preassembly the central frame


This assembly system is used to build industrial ladders and stairs. The connectors are inserted inside the aluminium tubes. They had a setscrew that presses the tube and hold ti. It can stand more that 200 kg.


Mounting the central frame in the lower body. I did some holes to pass the tubes.


I also insert the elbows and the cannon the same way I did with the eyes.




Monting the knees



Cutting the tubes


Drilling the tubes for the motor supports


Holes in the legs to pass the tubes


Mounting the front wheels


And the rear wheels with the motors. The motors are 2212 NPC DC Motors, similar to the ones used for wheelchairs. Imported from the USA


Detail of the wheels mounting



Much more to come...

 

I noticed the wheel assmblies in an earlier post. This is just getting good!
John

 

Some work with the electronics.
My first idea was to mount the batteries in the head, but there isnt enough space. So my plan is to mount the motherboard on the head, and the batteries on the backpack.



This is the motor controller, Roboteq AX2550, capable of manage 120 amps per channel, and conectable to an RC controller of a motherboard by serial port.
My motors have a maximun amps comsuption of 80 amps, stall.
To support the controller I am using a simple plastic tray, like the ones used in the kitchen.



The second level supports the motherboard and the power supply, special one that could be connected to a battery.



Some details





This is the control board. I also used a plastic tray.



From up to down, and left to right.
Motor battery switch; Motherboard power supply switch
Motor battery fuse; Diode bridge for batteries charge; motherboard battery fuse
Battery voltaje indicator (not showed); ground concentrator

Lot of cabling to prepare





50 mm section cable for motors power supply.

More tomorrow