RC Tank Warfare community hobby forum

Waves White Flag and seeks forgiveness....

Ok, I spent a looooong time building the excavator arm, and getting all of the motors to do what I wanted them to, but......
it was always a compromise between making something that I could fit the motors into, and making a scale model of something.

I thought that I was doing pretty well, but experiments and tests over the last week have taught me that there is going to be no getting away from the interference between the three RX18 boards and receivers that I have jammed into the lower hull. The AEV almost launched itself off worktops and the kitchen table a few times, it became totally unpredictable, and the range was reduced to a few yards. I even tried Alwyn's suggestion of three RX's onto one antennae but that didn't work either.

So, back to square one.

Designed a whole new excavator arm in Openscad, it had to be done in three sections, and despite my crappy engineering skills it has just come off the printer, and when clipped together it is exactly the correct length. This version will be static, or moved under human assistance as it has all of the hinges preprinted. Nowhere to put the motors though as the new sections are not hollow.

I intend to complete the build using the new arm, the dozer still functions, then if I need a project next winter I will take another look at it. I can modify and reprint the arms if I can figure out how to make a scale version work like the non-scale one did (eg cables running in PTFE tube, servo's, pet hamster etc. I have a few ideas knocking about but I have had enough of this problem for now.

RobG

Good Morning,
It's a wise man that knows when to cut and run until he can come back with a bigger gun. I know that you'll figure this out. Best ideas come along when you aren't even thinking about the issue. Looking forward til' then. Your printed arm is pretty sweet for the detail.
regards,
Painless

The new arm looks amazing Rob, great job. Re the electronics I don't suppose there would be any mileage in put foil wrap around/between the receivers and rx18s to shield from interference between boards? It seems an awful shame to have come so far and be thwarted on the last lap as it were. Alwyn

You can do it t Rob,

A solution will hit you from nowhere.

John

Nice work.

I came across this video and I thought of your build-

@Woz, lol, how on earth am I going to build a 1/16th scale Indian chappie???

@Alwyn, yes, I thought about Faraday cages, but everything was becoming a compromise. Doing it this way I end up with something that looks like the original, even if it is non-functional. I guess that this is where CAD software becomes useful, I have saved the code, so can simply go back to it at any time and modify to take tubes, servo's or motors. Clark has a TK60 in the wings, and I think I saw 10 channels mentioned somewhere. If it has multiple motor/servo support, with sounds for each one, it would be the ideal solution...as long as it's cheap enough.

I have been looking for a bigger gun.

I went for broke and have redesigned the arm so that it is a copy of the original. I have also put hollow cable runs inside the arms. This is only a rough print (only one of the arms didn't suffer from bed lifting, but I think I can solve that problem now), as I just wanted to test the theory. As the whole thing will look like the real one, it means that all of the pivots will work the same way too.

Due to the wonders of CAD and only needing to design it with accurate dimensions once, it means that I can build static hydraulic arms that will clip into the brackets on top of the arms. That way I have a quick fix 'nice model'.


It also means that I can build another set of hydraulic units that contain the electric motors that I salvaged out of the original, and run all of the wiring inside the arms, so it will still look all neat and tidy.

I was racking my brains about the interference, how was I going to solve that??

I gave the AEV a run around with an IBU2 installed, and Leopard sounds, and as always realistic sounds transform any tank, so I figured that this was one board that would have to go in.

The IBU has two way elevation...??

The old grey matter then starts working overtime....

IBU2 can control:

1. Both drive motors.
2. Dozer blade up and down on elevation.
3. Turntable on turret rotation.

If I get hold of an HL 2.4ghz RX18 I won't get interference. This can be used for:

4. Arm lift on turret rotation.
5&6. Bucket and last arm on drive motors (by pushing the stick far right and left I can control each motor independently or central and both go the same way - makes controlling an excavator very easy.

This leaves one motor to control on the middle section of the arm.

As all interference has now been eliminated, I could use a standard HL RX18 to control that, or tag that motor onto 5 & 6, less independent motor control but one less board to worry about. If I do it that way I don't even need the HL 2.4ghz as a standard RX18 won't get interference from the IBU.

This may all yet work out as I originally intended....

That sounds like a smart plan Rob, should look really good with the updated boom as well. I knew you'd figure something! Alwyn

Good Morning,
It didn't take you any time at all. Two different boards and Bob's Your Uncle. Congrats on figuring it out. Having a 3D Printer to bring ideas to life almost instantly was a very smart move on your part! Following along.
regards,
Painless

Been watching this build and i have to say Rob the 3d printing is fantastic !!
Well the hole build is as well but the 3d side is pretty amazing !
Im sat watching and waiting for the next instalment !