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Technically your team can consist of as many people as you like; often the more the better as you can pool resources to make a better robot(s). But as far as I'm aware, the limit of four people per team is to avoid overcrowding in the pits, so it might be better to limit the team to four (or form different teams) so that you don't have to pick and choose who goes to an event.
I'll do that then, it's a bit harsh to say to people "You can't go", so I'll do two-ish teams. Maybe 3, depending on what I can do. Luckily, my friend who's on the team can weld, and use CAD, along with quite a few engineering skills, so I know who may be more likely to be on the team.
So, it seems I've figured out a almost perfect team from my college, and hopefully, we should get a 3D Printed ant, or work on a feather, and maybe ideas drawn out for a heavy, maybe some scrounged motors or things. Just stuff for the future, after a quick scour of the forum, I realise it's a very bad idea to get into a heavy straight away. Or so it seems, as it's very costly to make one on more than bang bang speed controller, said wheelchair motors, and scrap. Basically, the same way as they were made back when robot wars first started, or so I believe.
I'm just embarking on an extremely budget heavy. I'll give you the heads up when I'm further in!
Hope it all goes well dude, I'll be following the build diary. I've seen adz's one, Ceros, and that looks pretty good. I may have to look for parts on the forum, or maybe see if the heavy Eric is still available, and spend some money on that. All being well, something may go right. We have all sorts at the college, Milling machines, Lathes, CNC machines, 3D Printers (Albeit them being small makerbots, though they'd be amazing for antweights). I've tried to make a bang bang servo/microswitch speed controller before, it didn't go too well, although some sort of relay should suffice nicely. barring that, I'm sure I've got one for a feather somewhere, and botbitz is supposedly cheap.
Yeah definitely, any robot building is still awesome whatever the level! I've made a few duff feathers to get an idea of the wiring etc.. All the ideas are easy to scale up or down its mostly just construction techniques that change as the robots get bigger. I'm finding it gets less blaggable lol.
I've not really made a feather althogether, but I've maintained around four, and a couple ants, so I should be in the clear to get going with a heavy, just some wheelchair motor driven thing. Any idea on what to do for a speed controller?
Well, question time again, this time for the future, may be near future, though.
First of all, how in the hell do you make a speed controller fit for a heavy? I'd settle for a cheap servo controlled one, as if I made a heavy, I'd not be able to afford a decent ESC. What Limit switches, ect... would I need to handle the current of the bot?
Thanks.
If this is a budget HW, I would say the relays you want would be 100A plus to do wheelchair motors or something like that. Anything bigger, you need a real controller. Also, I wouldn't be very keen on tech checking a relay and microswitch operated robot, so much to go wrong. You can use them, but extra measures to assure failsafe would be recommended.
You will find, driving into the arena with a bang bang system is going to be tricky :P
Fair enough, I may have to save up and fork out the extra money, so I can actually get into the arena, never mind fight in it.
Is there any recommendations for a good decent ESC? I know the Vyper is around 120, and does one motor, and I've heard Wottys are good, despite their price.
Do you have a link for this 'Vyper'
If you saved up and got a Wotty you wouldn't need another controller again, very good, and the repair service is second to none :).
It's the new Robotpower one, that was supposed to replace the Sidewinder AFAIK. http://www.robotpower.com/products/vyper_info.html
I've been looking at that actually, just forgot the name! Looks kinda like a Victor, and if those ratings hold true (which I think they do), they're a good controller, but it is $400 for a pair, adding in shipping; you would be just as well getting a Wotty.
Are wottys single motor controllers, and would you know their price? Thanks for the help so far, I think you may have just prevented a lot of hard work.
A Wotty is a dual motor controller and the standard Wotty is £370 posted. Takes up to 36v. Can't remember exactly the Amp rating per side..
What motors are you running? Out BotBitz 85As will be fine for most motors which have a stall current < 100A. $75AUD + P/h per side. You can run two if they have two sets of brushes.
Have a look at this thread if you want to see me doing stupid things with a pair of them on two brushes. http://robowars.org/forum/viewtopic....er=asc&start=0
I only had issues when I attempted to keep driving after I had burnt all the insulation off the motor windings..... I chose to keep battling than save my ESCs ;) the way it should be. I also worked out when I was melting connectors off 2 x XT90s I had to be pulling in excess of 400A through the ESCs for burst periods.
No idea how they compare to the wotty but I used them pretty successfully in my Middleweight, I just didn't have enough gearing.
Anyway every featherweight bot in Australia uses 85As now (except for a few still with XXLs or Victors) but I don't think anybody has bought anything else since we started selling them a few years ago.
Steve
Most heavies over here use Bosch 750 @36V. Not something a TZ 85 likes.
But a wheelchair motor @24V sounds plausible.
So is it worth trying the TZ85s? I will be running wheelchair motors, at 24v, with lack of access to much else.
One of the other Aus builders is using them on wheelchair motors for a different project (Motorised Lounge Chair) so could possibly work. Bosch 750 if you split brushes to 2 x TZ85as would probably also work.
This is all speculation given I have not personally tried them in combat.
Steve
On the other hand, using 4 TZ's @ £45 is an experiment that costs £180.
Just curious, why four?
Also, I've had a think about the Wotty, and I don't know if I could afford it, without some serious saving, and the team chipping in, and there's no Sunday jobs to help around here, sadly. Being 15 (Almost, 16 days), it's tough to get anything done.
Ah, most bigger motors have 4 brushes. These work together as 2 pairs of contacts , each pair doing half of the windings.
This is very obvious in the magmotors, who have 4 wires coming out.
I believe you can drive a Magmotor S28-150 with a pair of TZ85's, @ 5S
In the Bosch it's done by connecting the pairs on the brush-holder. And that is what Marto suggests, decouple the pairs, and control each pair with a TZ85.
For non-overvolted wheelchairs, a TZ85 will do fine, especialy when you add a fan to the speedo's. Don't expect any world shattering speed or acceleration, but it will move, and if done well, you can build yourself a cheap bot that can take serious punishment. Just use thick enough steel and shock mounting. A nice bodyshell with a cool paintjob, and you'll have a great starter heavy.
Don't buy anything for a heavy yet. Build something small n get used to it all first :) The main problem with the smaller controllers is that they get hot. Even though there are small controllers with the amps rating, a small plastic box cannot dissipate the heat a big meaty dual controller can. Buying four small controllers divided between two big motors will be a nightmare to cable and set up.
I may get moaned at for costing someone a sale but £180 would nearly buy you a good quality dual controller. I am by no means an experienced robot builder, but I am an experienced electronics technician by trade. Please message me if you need any help and ask questions before you spend money.
@Maddox - That does seem a hassle, and might not work as well, despite being lower cost. I may invest into a Vyper, or a Wotty, depending on what happens.
@Daveimi - I see your point, but the thing is I've done that, bought a couple feathers, and built, smashed and rebuilt more. McCheapo, Shazam, and the original version of McCheapo, what was to be called something else, never worked out, sadly. I could never get them to work, and hated them, to be honest. I'll try to get one feather actually working, although I was close to one, I just never got it going. I'll post updates on McCheapo, the Wonky Wheeled, Weaponless Wonder. As in, "I wonder how that even got into the arena?" I'll be wiring it up soonish, I have all the components.
Yeah I mean it's hard not to sound condescending and I have no idea of your building experience, you're probably a better fabricator than me! I just couldn't stand by whilst you put nearly £200 down for something your not sure about wiring and so on.
Try an pick up a pair of 2nd hand 4QDs, will handle whelchair motors easily, not the nest control in the world but fine if your only running wheelchair motors. Pair normally go for around £100.
Josh,
I've got a pair of 4QD's nc70 or something like that I can't quite remember. Will have a look for you tomorrow if you're interested.
Harry
brand new un boxed including rc interface form 4qd would be round £230 ish, looks like they have stopped doing the ncc version and are making one called vtx instead.... seems pretty similar
http://www.4qd.co.uk/prod/vtx.html
http://www.4qd.co.uk/accs/dmr3.html
What are the stats on your wheelchairmotors? The ones I handled in the past were rated up to 400W, on 24V that means less than 20 amps. (mobility scooters are another matter, and can go as high as 1kw on the single motor that drives the dif)
Even if we stick to the rule of the tumb that a brushed motor does 4 times nominal current in stall it won't blow the TZ85's.
But if you want to be sure, go for the Wotty. Then you support a roboteer. Buy British manufacture and have super fast and accurate repair work if needed. And it's made for our purpose...
Well, I may have to see what happens. I may be buying Eric from antazz, if it's still available, and making my own modifications (Both cosmetic and internal) to it. I just don't have the skill and confidence to build a heavy from scratch, but to have one that I can run and repair, builds confidence. I may end up going into building one from the start, it all depends on what I can deal with. I tend to learn by having a finished one in front of me, to maintain, so I can understand what I'm dealing with.
Harry, I'll probably be interested in those 4QDs if you can find them. I'll PM you.
Thanks for the support everyone, it's really helped me understand what I'm dealing with, again.
Hooray, more questions!
Anyway, I'm looking on ebay for a good Linear Actuator to suit my to be heavyweight robot. Is that the best place? Is there any recommended ones?
Give Ewan a shout
http://www.gimsonrobotics.co.uk/12V-...actuators.html
That GLA750-S looks mighty tempting, but I'll have to measure up before I do anything.
You will need to cleverly support the lifting arm and make it impossible for the actuator itself to bear any impacts; if you land on the open lifter, you're talking hundreds of kgs of force being fed right into the actuator, and it will not enjoy that for long. This is the case in any scale of machine but is more pronounced on the heavyweight scale.
Well, it seems a lot less costly than Pneumatics, but I feel they're more robust. Maybe I shall just save, and learn pneumatics, there's more than enough links on the thread, and I know the dangers of the stuff. Hmm... I'll need to have a good think about this. I could try motor driven, but I know that'll be a pain to set up. I see why most people use pneumatics. It's just a problem of, if I can't do pneumatics, and I have no weaponry or ability to self right, it'd make a rubbish robot... Is it possible to run on low pressure easily enough? Or would that not be worth the effort?
I can't comment on pneumatic systems, don't know much about them, but I do know we have enough pneumatic heavyweights to last a lifetime. :)
If you can even consider a pneumatics system as a potential weapon power then you can definitely consider motor/gearbox driven, in terms of complexity. I don't know if off the shelf gearboxes that'd be suitable for not that much exist, but I'm sure something is possible. All Sewer Snake, an electrically powered HW lifter/flipper in the US (several times Champion) has, is a heavily geared down HW drive motor leading to a weapon arm by chain and sprocket. As it happens, what we based Tormenta 2's weaponry on. In principle, at least, it's far less complicated than pneumatics and something almost completely fresh for the current UK scene.
I think the problem you've got with Linear Actuators is that, compared to the equivalent pneumatics, they're really slow for a similar effect. I think the only advantages you've got is that they're more compact from what I know, they're not governed by Co2 supply (though that doesn't really bother many flippers I don't think) and they're a lot more controlled. I'd personally go with what Ellis said, a highly geared down lifter/flipper - whilst it may not give you the sheer throw of a flipper, you'll have a lot more control over the weapon, not to mention something quite unique! Of course, I'm sure you already know most of this...
Here's a video that might help you out, it's a rundown of Sewer Snake's innards on Youtube - https://www.youtube.com/watch?v=Pt6_dXKwQYw - I think the system is an S28-150 Magmotor on a 75:1 ratio, across a 2 stage gearbox and a 3:1 chain reduction.
I think it's a slightly older version, but I'd guess the principle stays the same. One thing to note is that, again, unless anything's changed recently, there's no limit switches on the weapon, meaning you'd have to be careful not to have it turn too much and snap the chain, if you do go that route.
So, since I have no chance of affording a Magmotor, of any kind, what motor shall I use? I doubt a Wheelchair motor would give enough power, and a scooter motor? No chance.
Starter motor? I think it only goes one way but you could have some kind of spring return which would help keep it on the floor. Weighs a ton but cheap and has tons of power.
I have some scooter motors at 850w they are also used in tomahawk,are easy to use and just use a sprocket straight to the wheels as they are low rpm but not been fitted but build quality looks great they are available of ebay