Simple first bot.

[Ellis]

Hello, I made a thread here some time before crimbo '09 preparing to build my first featherweight. The idea just kind of died, as money was an issue and it never really took off. I've learnt alot since that old post so here are my plans for a bot, this time for real.

Remember, this is my first time building a full scale (it's a feather, but you know what I mean :P) bot, so cheapness and simplicity is a must!

Right, here goes:
Starting from the bottom up, I'll hopefully be using 4 rollerblade wheels. They're robust and are pretty grippy.

For motors I'm pretty set on 4 of these: http://www.argos.co.uk/static/Product/p ... +DRILL.htm (WOULD LIKE SOME OPINIONS! )

I am not sure howmany of these ESC's. I'm guessing two, two being maximum really (price!): http://www.electronize.co.uk/FR12VR_spec.htm (Probably mean I'll end up with 2 motors and 2 wheels, lol, oh well)

For chassis there are loads of local railing and window frame-like builders around, this shouldn't be a problem. Likely to be heavy though.

Pretty much the same story for a shell. Although since this bot won't be for competing, I probably won't bother.

This radio system: http://www.sussex-model-centre.co.uk/sh ... p?id=29064 (cheap, recommended, 2.4Ghz, what more could you want? :P)

Hmm.
What else? I think that's about it. I plan to make a very powerful box. 2 motors is kind of not what I wanted, maybe someone could recommend some more powerful motors that would work with 2 ESC's within the £60 price range? (30 each) if not just throw anything at me lol.

I think that's about it.

P.S. are ESC's REALLY necessary? I mean, either full pelt or nothing will be pretty awkward, but for a test... ?

Thanks in advance,
Ellis

[psycho_fling]

Re: Simple first bot.

yeh there is little point in making a combat robot with no speedos

you will need a max of 2 speedos its one esc per side so you can have 4 motors on 2 escs

all the links are fine, but i would recommend a dual speedo bit more modern and give great responses

any cads or owt???
alex

[Ellis]

Re: Simple first bot.

Ok, thanks for the heads up.

And not really, no. Just imagine a remote control shopping trolley and you're pretty much there.

[typhoon_driver]

Re: Simple first bot.

Here's a hint, this hobby WILL cost you money. For a standard featherweight rammer, you're looking at around 150 to 200 quid and believe me that's cheap! That used to be the price of a transmitter alone!

I can understand trying to make something for nothing but if im being honest if you want to have something of any use in the arena one day then it's better to spend a bit of cash now and get some usable parts.

O and don't worry about the electronize being up to date been using them for years no bother with drills.

[Ellis]

Re: Simple first bot.

I am expecting aroung 150-200 anyway, and I live in Spain so it's very unlikely I'll be entering any comps any time soon.

Maybe I can start my own thing over here. Various friends of mine are massively interested in anything that goes BANG.

So this list is about right? I can start ordering now you think?

[RogueTwoRobots]

Re: Simple first bot.

Going on what you've listed and what you'd like, here's a possible option:

The speedos you've linked to don't have a high enough rating to run two drill motors each, so 4-wheel drive is out of the question. But what you can do is put 4 wheels on your robot but only connect two of them to drill motors. If you connect the two diagonal ones to drill motors you will have something that is not too different from full 4-wheel drive in terms of handling but which only requires two drive motors. That way, you can keep the cost low with the speed controllers and, if you buy four drill motors, you'll have two spare motors.

Are speedos really necessary you ask? Not at all. The full-pelt or nothing method of using micro switches operated by servos to control your robot will do the job. Not the nicest job, but they will allow you a degree of control over your machine. Driving 2-wheel drive robots with switches can be difficult but with a 4-wheel diagonal drive setup it is a bit easier, as the two idling wheels give a little bit of friction to prevent the robot from spinning wildly when you turn and also help to keep it going in a straight line.

Ancient video time!!
This video illustrates the idea mentioned above. It's got four wheels (well, was meant to, but only has three, lost the other one ) but only the two diagonal wheels are driven by drill motors. Control is provided by micro switches operated by RC servos:

http://s31.photobucket.com/albums/c367/ ... t_0001.flv

[Ellis]

Re: Simple first bot.

Hm. Okay, well, could you link me to some suitable speed controllers? I want 4 motors and will do pretty much anything to have them. :twisted:

I'll get ordering everything tomorrow, for now, bed.

[psycho_fling]

Re: Simple first bot.

it would have to be i think (not sure) a dual speedo but with that you need to make sure that each channel can take the combine stall current of 2 drill motors

[zoll]

Re: Simple first bot.

Hi, firstly let me say by no means am I an expert I have only just built my first robot. I too wanted to use 4 drill motors and had the burning question of which ESC to use. You may find the descussion in my thread helpful [ur=http://www.fightingrobots.co.uk/forum/viewtopic.php?f=164&t=3000l]here[/url] for a number of options.

For me I found that things most people where suggesting where about £100+ and there wasnt a general consensous they would certainly work. In the end I went for a Wotty100 which set me back ~£180 back. There is the also this which is very similar in both spec and price.

For me anything cheaper wasnt really worth the gamble of blowing £100 speedo when i stalled the robot.

[Ellis]

Re: Simple first bot.

Well, ok, I've gone for two of these: http://www.electronize.co.uk/model_elec ... frames.htm (FR15HVR). If anyone strongly objects, please do so ASAP, I'll probably be ordering them tonight.

I am going for the Planet 5 2.4Ghz transmitter and reciever shown above.

I've gone for the slightly more expensive ESC's because the drills I was going to get don't get delivered to Spain, and they don't even exist over here. I'll be going tomorrow after school to check out some cheap drills locally. It's just on all the websites I've visited, they've been pretty expensive.

Oh and I know it's possible these two ESC's won't be able to run 4 drills, I might end up having to settle for a 2 motor bot :c...

Which is still ok, since I'm not going to be entering anything for now, lol.
Thanks for the helpful comments guys, much appreciate 'em.

[zoll]

Re: Simple first bot.

I think they should work for two drill motors fine but I very much dout 4

[Ellis]

Re: Simple first bot.

Sigh.

Okay, well, I guess that makes things a good deal cheaper. I'll over volt them for the extra bit of juice. Thanks.

[typhoon_driver]

Re: Simple first bot.

you could always run a pulley and belt between the wheels on each side to give you 4wd on 2 motors.

I think you will be surprised at the power that 2 motors have.

[Ellis]

Re: Simple first bot.

Well, after speaking with Grant (thanks!), if I can persuade my parents just a bit more, I'll be going for the 30A ESC, not the 15. This should run 4 motors ok.

We'll see.

[Ellis]

Re: Simple first bot.

Bought the four drills today, ordering the ESCs and the Transmitter/Reciever set tomorrow, will have access to some chassis-like material next week aaaand I couldn't be happier.

Might start a build diary.