General questions for first robot

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Shrike
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General questions for first robot

Post by Shrike » Sun Mar 04, 2012 5:40 pm

Hello everyone, I am new to making ant weight robots, but I have some experience with simple autonomous robots. I was wondering if someone could help me answer a few questions before I start making an ant weight robot.

As of yet, the plan is to make a 2 wheeled robot with either a horizontal spinner, or one similar to that of robot wars antweight, Combatant. I am aware that making a spinner for the first time is unadvised, but I like a challenge, and the main reason I am into robotics is because of heavyweight spinners such as hypnodisc and tornado.

The robot will be invertible to combat flippers, hence the horizontal weapon. I want it to work like hypnodiscs, in that it does not cut, but bludgeons the opponent. However, I do not know what to make the weapon out of? Unfortunately, I do not have any metalworking tools, so I cannot make a fully custom blade. Does anyone have any suggestions on what I can do instead?

Also, is sintra an ok material to use for a chassis? It is reasonably hard but easy to work with, and whilst I do plan to use some metal (probably aluminium) on the chassis for defence, sintra is an easily accessed material. What do you all think?

Any comments are welcome :)
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Re: General questions for first robot

Post by Remote-Controlled Dave » Sun Mar 04, 2012 6:47 pm

Hello and welcome aboard!

If you are dead set on going the spinning disc route but don't have the skills or tools to fashion one, I would recommend putting a request on here (or the German forum) to pay to get one made up for you. Discs are difficult to build without much skill, and even if you can get something spinning and balanced, it wouldn't be as effective as the ones some people can machine for you. I've been down that road myself, so that would be what I recommend. It's much easier too!

I'm not actually sure what sintra is, so I can't give my opinion on it! It's not something I've come across in all my years doing ants. Maybe someone else has an opinion on it, but I wouldn't say its very widely used here in the UK.

Hope this helps.
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joey_picus
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Re: General questions for first robot

Post by joey_picus » Sun Mar 04, 2012 6:49 pm

Hiya, welcome to the sport :) (I must say your English is really good, assuming it's not your native language, but even if that is the case ^^)

The Combatant spinner concept unfortunately proves problematic if you catch the opponent with the wrong side of the spinner, and Combatant itself now uses a more conventional vertical spinner, so a horizontal spinner would be the easier and more effective of the two concepts (although you could make a vertical spinner work inverted - look at The Executioner from series 7 as a good example, or the present day Combatant). As far as manufacturing the weapon goes, titanium or stainless steel would probably be the best choice, and the latter is available as ~1mm thick rulers from decent bookshops/stationery stores, which handily have enough markings on to be able to cut a very precise blade out and locate holes for mounting the motor :) For the motor itself, the vast majority of current antweight spinners use a brushless outrunner motor to directly drive the weapon at high speed rather than any sort of gear reduction.

I can't comment on sintra for a chassis as I've shamefully never used it! - my robots tend to have a chassis of polycarbonate, about 1.5mm thick would be enough to support a spinner I would think. The alternative would be to use carbon fibre or PCB fibreglass board, which I believe Peter Waller uses and would provide more than enough stiffness for its weight.

You're right in that spinners are difficult machines to build, but you do seem to have a good idea of what you're doing so good luck to you, just please remember to stay safe ^^ Hope this all helps you!
Joey McConnell-Farber - Team Picus Telerobotics - http://picus.org.uk/ - @joey_picus
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Shrike
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Re: General questions for first robot

Post by Shrike » Sun Mar 04, 2012 7:00 pm

Thank you very much for the comments. As much as I would love to say that I have practiced English really hard, I am in fact a native speaker from Southern England, who is living in Germany for family reasons.

Sintra (for those who do not know what it is) is a form of PVC foamboard, which comes in 1mm,2mm and 6mm thickness. I was planning to use it as it is a material that I already have, and it does not break easily.

As for the blade, I will see what I can do by myself, and the advice given. I know that my grandfather has done metalwork in the past, and I am sure that he might have some bits of material lying around to make a 'bar blade'. Or, I can see if there is something at the same place I plan to get aluminium from that I can alter into a weapon. As for asking the online forum, I will have to see if that is an option I can do.

Another problem I have is what receiver to use, and what speed controller for the disc motor. As of yet, most of my electronics come from active-robots.com, as their warehouse is conveniently near where I lived when I was in England :) can anyone suggest a uk website that has receivers and single motor controllers, and possibly even particular ones to look out for?
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Re: General questions for first robot

Post by Remote-Controlled Dave » Sun Mar 04, 2012 7:34 pm

Regarding recievers, I would assume you are running a Spektrum (or similar) system, rather than a 40mhz set with crystals?
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Shrike
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Re: General questions for first robot

Post by Shrike » Sun Mar 04, 2012 7:39 pm

Probably something like that, I would like to avoid crystals if possible.
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Re: General questions for first robot

Post by Remote-Controlled Dave » Sun Mar 04, 2012 7:50 pm

In that case, I highly recommend Micron for components. Its where I get all my batteries and receivers.

http://www.micronradiocontrol.co.uk/rx_dsm2.html

I cannot recommend the DSM2 'Orange' receiver enough (2nd one down on that link). They're cheap, reliable, lightweight and small. As long as you get a compatable TX, that's the reciever I would always recommend.

For spinner controllers, I'd recommend www.robotbirds.com. They have a huge selection, you would definitely find a good few options on there.
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Re: General questions for first robot

Post by joey_picus » Sun Mar 04, 2012 7:53 pm

Avoiding crystals is only part of it, I found that my initial robots were virtually uncontrollable when I was using 40mhz and apparently having many handsets running on Spektrum or similar setups - as is the case at recent events - seems to flood the 40mhz band with noise and make the problem worse :(

Aluminium for a weapon bar might work, although using something a bit harder for the teeth might work better as it's possible the bar rather than the opponent would break against some of the titanium armoured ants around these days! I know Antipathy uses a ~6mm aluminium bar with Stanley knife blades, which works quite well, so it may be worth having a word with Gary Aylward about that (BeligerAnt on the forums).

Micron and Robot Bits are two of the main sites I use to get robot bits from (I have looked at Active Robots but have yet to think of enough to buy to justify a full order, hehe) and you can probably get just about everything electronic (motors, wheels, weapon motors, speed controllers for brushless motors, batteries, radio gear) you need for an antweight between them. The one exception is speed controllers for brushed drive motors, which in about 60% of active antweights come from our own Peter Waller's prototypes, although I *think* Robot Bits and Active Robots sell the Sabertooth 5a which would also work.
Joey McConnell-Farber - Team Picus Telerobotics - http://picus.org.uk/ - @joey_picus
"These dreams go on when I close my eyes...every second of the night, I live another life"

Shrike
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Joined: Sun Mar 04, 2012 4:18 pm
Location: Hannover, Germany

Re: General questions for first robot

Post by Shrike » Sun Mar 04, 2012 8:00 pm

I will look at these websites in detail later on. Thank you very much for the quick responses!

As of yet, I intend to use the sabertooth 5A for the motors, with these motors being active robots product GM14A.

On a minor note, I was thinking of calling it either Typhon, Loki or Grendel. What do you think?
Doing nothing is hard to do, as you never know when you are finished.

Gizz
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Re: General questions for first robot

Post by Gizz » Wed Mar 07, 2012 12:48 pm

I can recommend http://www.botbitz.com/ for speed controllers aswell, Im running 2 of em in one of my bots and got 2 more for my next build and they work very well so far. The shipping time isn't too bad considering its sent from australia and the fee isn't that high either.
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