Build Log | Caractacus - Any Tips?

[willcaddy]

Hello everyone!

Ive taken the plunge and decided that im going to start work on my Featherweight robot "Caractacus", named after Caractacus Potts from Chitty Chitty Bang Bang because of the mad inventor scenario xD



I have bought a Spektrum DX6i transmitter after asking a few questions down at Robot Wars Live Gloucester as well as some research online.

I was just wondering if you guys could give me a few tips based on your experience?

A few main questions I have is:
- Would you recommend a Spektrum receiver and if so/not which would you recommend?
- Im looking at a steam punk look but would iron/steel be too heavy as armor?
- Im looking at using the BotBitz 85AMP Electronic Speed Control (v2) as I looking at cordless drill motors. Thoughts?
- Is CAD design worth doing? and if so, what software would you recommend?
- Any other general tips?

Any information at this stage is very much appreciated! I eagerly await your responses!

Thanks a lot

Will :-)

Edit: Forgot to ask something ¬_¬ lol. I have been looking into batteries and chargers and I hear Turnigy are good. Any recommendations for both? Thanks xD


Build Log Videos!

[R9000]

Hahah! Well that's an interesting name, it's been a long time since I watched Chitty Chitty Bang Bang. Let's get to these questions:

-Spektrum receivers seem fine, I have an AR610 to go with my DX6i and it seems perfectly adequate. There was a discussion not long ago, have a look: http://www.fightingrobots.co.uk/thre...obotwars-arena

-You don't want pure iron, I think barely anything's made out of iron these days, too heavy and brittle. Hardox (a form of steel used as a wearplate) is commonly used in most robots. It's heavier than plastics or Aluminium, but very very hard. You'll want to keep weight in mind when deciding how much you want on your robot and at what thickness, but quite a few people use Hardox on their featherweights, like Omega, but keep in mind that's a rambot with no weight taken up by a weapon mechanism. Actually, check out Team PP3D's 'Getting Started' guide for a really good rundown of different armour and chassis materials: http://pp3d.weebly.com/getting-started

-Yes Ranglebox's 85A ESCs will do fine for a featherweight, as will drill motors. Just be prepared to find a wheel that'll fit on the 3/8 UNF thread.

-If you can use CAD programs, go for it! I find it helps get a much better visualisation of your robot before you go buying up all the parts you need, or ordering waterjet-cut steel. I used Sketchup, but if you're experienced with more advanced CAD programs like Solidworks or Autodesk, they'll probably help you estimate weight as well, among other things.

-As for general tips, I'd say just make sure you plan stuff out before you buy. The less money you waste on unneeded or incompatible parts, the better. Also personally, I'd advise doing your wiring last. I wired my electronics up before I finished the chassis, and all the moving about has played hell with my soldering. Though I did use quite stiff wire, so that has undoubtedly contributed. I'll be doing a rewire once I'm finished with nice flexible AWG silicone-coated wire. Others will have plenty more tips for you, they'll probably know more than I. :P

Best of luck!

[willcaddy]

Thanks a lot for the reply! Some awesome feedback :-) Also glad you like the name ha ha!

Out of interest, what is your robot? I'm always interested in seeing other peoples projects!

Thanks again! :-)

[RogueTwoRobots]

I want to see how the commentator copes in a three way meleé with Caractacus, Carcinus and Cerastes

[willcaddy]

YES! That will be amazing xD

[R9000]

Here's my build diary thread since you asked, I haven't updated in a while but I've been quietly working on it these last few months - it's getting near to completion.

http://www.fightingrobots.co.uk/thre...d-lifter-aegis

[willcaddy]

Here's my build diary thread since you asked, I haven't updated in a while but I've been quietly working on it these last few months - it's getting near to completion.

http://www.fightingrobots.co.uk/thre...d-lifter-aegis

Mate, that looks sweet! :-) Cant wait to see it in action!

[willcaddy]

I forgot to ask before -_- but what would you recommend battery and charger wise? I have been looking at the Turnigy LiPo battery's. Any thoughts?

Thanks xD

[maddox10]

Team RCC has a few Turnigy's in use. If the mAh and C rating is chosen well, no problem.

[lowndsy]

Wireless Madness have a bunch of batteries that I haven't seen anywhere else. Not heard of the brands, but they were good for my rc gear the batteries have the connectors for balance chargers too which I didn't spot on the cheaper ones.

I was going to string 2 x 7.4v (for a 15V motor) together, but they have some 14.8 V ones that look tasty. What do people think of this one?

https://www.wirelessmadness.com/peak...ector-pek00554

[willcaddy]

Team RCC has a few Turnigy's in use. If the mAh and C rating is chosen well, no problem.

Thanks a lot :-)

Wireless Madness have a bunch of batteries that I haven't seen anywhere else. Not heard of the brands, but they were good for my rc gear the batteries have the connectors for balance chargers too which I didn't spot on the cheaper ones.

I was going to string 2 x 7.4v (for a 15V motor) together, but they have some 14.8 V ones that look tasty. What do people think of this one?

https://www.wirelessmadness.com/peak...ector-pek00554

Thanks xD

Just as a side note so im not doing anything dense lol but if you run 18v drill motors then the machine runs at 18v right? As apposed to doubling it to 36v (2 x 18v drills). I think I know the answer but just making sure ha ha!

Thanks again for all your help :-)

[willcaddy]

Did a bit of concept art while I am waiting for parts to arrive xD

Its not to scale or anything xD but let me know what you think and any suggestions :-)



Thanks again xD

[lowndsy]

Yep, 18v

[willcaddy]

UPDATE: First step video also quick question about ESC's :-)

Hey guys,

Did a video of the first step of the build!

I intend to go on to speed controllers next.

https://youtu.be/aT_fAvAjVGw

Let me know what you think!

Just a quick question, do you think the BotBitz 30a Brushed ESCs would be good enough for a featherweight robot like this or do you think bite the bullet and go for the BotBitz 85a Brushed ESCs?

Thanks a lot

Will

[maddox10]

The 30 amp ESC's will do the job for a 2WD machine with batterydrills.
But once you go for more power,like using Ranglebox Saturns, or the old style Groupner Speed 900 it will get iffy.

The Tz85's have proven to be rock solid, so I would suggest to bite the bullet.

It's also easier to find replacements during life events, as a lot of UK feathers use the 85's.