Wanted: Featherweight bot

[Lostdreamer]

Ooh, new series of robot wars is out.

And I still can't get the thoughts of how much fun getting involved might be.

So it's time to get stuck in.

And the sensible part of my brain says that I should start with a featherweight to get a better idea of what is involved and because it's likely to be a much quicker and easier way to get to the stage of competing and 'learn by doing'.

In the spirit of 'stop talking and do it already' it occurs to me than an excellent starting point would be a robot that is already mostly complete. In a perfect world something that is ready to fight out of the box would be great, but mostly i'm interested in something I can cannibalize the control hardware and drive train from.

All of which takes us to the question of the moment:
Does anyone have an old feather (in mostly running order) in their shed that they arn't using any more and would like to turn into cold, hard cash to fund other robot projects?


Cheers

[typhoon_driver]

Drive train - a couple of cordless drills stripped down
Control hardware - an off the shelf speed controller such as the modified Tz85 or ragebridge

You'll learn a whole lot more building yourself.

[maddox10]

1) Building a robot yourself is the best experience.²
2) Buying a decent feather isn't cheap.³

² but with help from experienced roboteers you can avoid a lot of pitfalls and moneysinks.(and having the basic tools available helps too)
³ even the cheapest featherweight ready to run will cost you £200, and then you have a wooden or cutting board armored box. A full balls out weapons blazing titanium monster can easely go £2000+

[shakesc]

message Shakey on the forum
He is thinking of selling a couple

[Lostdreamer]

Yes. I can build it myself, and I intend to significantly rework whatever I get.

There are plenty of guides for making entry level bots, and none of the stuff in there worries me much. I'm confident I can cut up a few cordless drills and wire in an off the shelf controller. In part I was curious if I could pick up a second hand bot for less than I could build one for. I'm not after top end, just the cast offs from someone else who has been here and gone through this process before.

But it's also I simply don't know what is involved - and therefore what I want from the robot - until I've done it.

So the plan is something along the lines of:

Get an 'out of the box' solution that I know works.
Enter a match, see what happens.
Then take it apart and rework it to my own design.
Enter some more matches, and test it thoroughly.
Then sit down and get stuck into building the heavy to compete in robot wars and get my ass handed to me.
...then sit down and get stuck into reworking that...etc, etc, etc.

But in the same way as it seems sensible not to skip straight to the 'build a heavy' stage, I think before I try and compete with my robot I want to start with something I know works and learn what is involved in the competition.

I hope that makes some sense...

[Ocracoke]

I can see the sense in doing what you are planning but to make a basic rambot in the FW class is reasonably cheap to do. A verrrryyyy basic design, like a wedge rambot like The Honey Badger 2.0 would probably involve the following costs (and this is assuming all new stuff):

- Transmitter: £40
- 2x speed controllers: £80 for the pair (using the TZ85A example - cheaper if you can find someone to do the reprogramming for you but not by much)
- Geared motors - £40
- Batteries + Charger - £60
- Assorted small bits (mixer, wiring, connectors etc) - £30
- Amour/chassis stuff (assuming HDPE as the main constituent here) - £70
= £320 (estimated)

Of course, it is the experience in building it that is priceless. The Honey Badger 2.0 cost me roughly £400 odd to build (and that includes bits from the original Badger) but I've learnt a lot about how to build a effective robot from that which will go into other robots I plan to make next year.

If you buy another person's robot, you inherit the builders methodology for building it, which includes things like wiring and so on and that can be risky if you don't get why they did what they did in that robot.

[Deathly Hallows]

I can recommend the Haynes - Robot Wars book if you want a place to start. There is a pictorial instruction for a featherweight and heavy weight. That's what made me decide I would take the plunge. ISBN 978 1 78521 186 7
They explain how to re-purpose drill motors etc.

[Roboteernat]

Lostdreamer, where are you located?

[Lostdreamer]

I'm midlands based, but not against a bit of exploring.

[Theo]

I partially agree with the others. I knew the electeonics side and it seemed pretty straight forward but didn't have the equipment or expertise to make a chassis/shell and Harry just so happened to have an excellent one for sale. My advice would be to ask around for a shell (2WD wedge ideally, learn the basics) and work from there. A drill and Dremel will go a long way if you're just working with HDPE. The electronics are much simpler than you may think and just require basic knowledge and soldering skills. When you have a physical design to work with, knowing the ins and outs of it can help you a lot with upgrades. In short, buy a pre-made shell and do the electronics yourself.

[Lostdreamer]

The concept for the heavy i'm working towards is to build an axebot into an HGV wheel rim trying to design/build for durability rather than out-and-out firepower. Lots of bots don't seem to finish fights so i'm hoping logic of 'to finish first one must first finish' would make me fairly competitive.

There is plenty of prior art out there, so I know it can be done.
The wheel rim is a significant weight penalty and a packaging nightmare, but hopefully it makes the robot chassis/armour a service item that can be replaced between matches if needed.

What I would like to explore with the feather is:
Getting used to building/working with that packaging constraint. I'll probably use a mini wheel or something as a body.
Getting used to working with HDPE. I havn't done much work with it before. It doesn't look too hard to work, but it's quite abrasion resistant which could be a problem and it isn't really on speaking terms with adhesives.
Finding out what breaks and why so I can design against it. I assume this is a big part of the sport, but that's kinda one of the reasons for being curious if someone had something suitable in their shed. The main thing I want to learn with the feather isn't actually the design/construction (a lot of which changes when I upscale it and add an axe anyhow) it's a much more detailed knowledge of what happens during matches and how to go about damage avoidance/limitation.

Books are on order - how did I miss the fact there was already a haynes manual!?! Of course there is, there is a haynes manual for everything!

Next stop ebay for some parts.

[mrsam]

I have an axe feather that for a good enough offer I’d consider selling, there’s a for sale thread up and tonnes of videos of it on YouTube if you want to do some research

[Lostdreamer]

I have an axe feather that for a good enough offer I’d consider selling, there’s a for sale thread up and tonnes of videos of it on YouTube if you want to do some research

Oooh! Very shiny.

But, sadly, not quite what I am looking for as an entry point.

I'm much more interested in the driveline and control hardware than the weapon at this stage.

As I understand it, rambots are quite viable at featherweight (I could be mistaken) so weaponry is a later problem.
Possibly a much later problem that can weight until I start the full heavyweight build.

I'm thinking of something cheap and cheerful that I can mess around with. I want to mess around with combat robots damnit! It'll be back to the drawing board after the first few fights anyway so I may as well shortcut the process slightly by starting with someone else's £300 B&Q special.

...but there is nothing stopping me knocking up a £300 B&Q special myself and people are doing a reasonable job of convincing me that is the way forward.

[Ocracoke]

As I say, it is the whole "building it yourself" process that is the reward for the investment plus you get to intimately know how your robot works. The drive electronics/mechanics are fairly simple to understand once you know the language that comes with it.

My original robot, The Honey Badger 1.0 used little more than a wooden garden planter from B&Q frame as a chassis, a aluminium lampshade as a shell, 2x eBay motors, 2x speed controllers from RC cars, 2x aeroplane model wheels, a castor ball and a remote control transmitter (and that was the most expensive single part of the entire thing).

If you ignore the spinning flail that came with it, it came to roughly £180 and that was with a special tank RC transmitter that was £90 because I didn't understand what mixing was. Now it didn't work very well and only went through one fight before being absolutely flattened but the point is that I learnt oh so much from doing it myself.

Refitting another robot with your own electronics isn't a bad idea in of itself and you really wanted to, you could just remove the axe... (controversial I know, I'd keep it in a heartbeat).

[Andy1979]

Hi sam. Did you get my message? You gave me a price and i replied