New To Robotics
 

I signed up for this electronics course to fill one of my spares a couple of weeks ago, and we're going to be doing this battlebots project - just sumo and racing and basic stuff, but they aren't wireless. I was wondering what prices would be like to make them wireless? I have Googled stuff and unfortunately everything is blocked (that I found anyway).

I want to make one that would spin, yet go forward at the same time, and just part suggestions, I was thinking about gutting a drill and using that motor for the spinning part, and use a potentiometer (spelling - again, I'm new to electronics) and such. Any sort of help in the area would be great. Thanks.

Re: New To Robotics
 

Well, if you look around you can get a VEX kit for $150 at radioshack.

I'm not sure of the legality of that for your class, but a VEX kit could be adapted for that and it provides a decent amount of inputs and outpus for that price. It is also pretty easy to program.

Re: New To Robotics
 

About drills: There's a great whitepaper by Joe P called Nothing but DeWalts:
http://www.chiefdelphi.com/media/papers/download/1589

It was written for FRC, but you can get an idea of some of the steps involved and pricing of using drill motors and fitting them to your robot. :)

Re: New To Robotics
 

What does FRC mean?

Oh and I skimmed thru that article and to me its just :eek:

Re: New To Robotics
 

First Robotics Competition. The FRC teams are the ones that build the large bots seen here: http://www.usfirst.org/robotics/

Re: New To Robotics
 

Check out my last post. I skimmed thru that and I didn't understand it at all.

Oh and a few other questions:

Everything is done thru wiring, but that wouldn't be considered "programming" it - or no?

If you do all the work yourself, would you still be called that?

Oh and on my prof I just put the name of my bot for the team. I woke up at like 3:30 one morning thinking of designs and it stuck with me.

Re: New To Robotics
 

Well... that's not quite what you're wanting to do. Basically, their taking the transmission (the gearing and such as that) off the Dewalt and fitting it to one of the motors that already come with the FRC robot kit.

I think you'll be taking the housing off the motor and transmission on the drill and using both to power your battlebot thing. You can see the pricing of the drill there in the whitepaper though as well as how to assemble the drill using other motors, how to fit it for a chain, and some other random things.

Re: New To Robotics
 

This forum is meant to be about FIRST, not random battlebots. So while alot of the info will apply, certainly not all of it will.

Re: New To Robotics
 

There are no kits or anything. We make everything from scratch. We're required to wire it and all we get are the parts, and we can buy them ourselves too. The bot has to be within 20 cm x 20 cm by 20 cm or 8" x 8" x 8" for the imperial users.

(2.54 cm = 1 inch)

Edit: And I added more to my post again before...

I didn't really know where to put this chris so I apologize.

Re: New To Robotics
 

Wow, small size. What is the purpose of the bot? Destroy everything?

Re: New To Robotics
 

Okay I'll be a bit more specific...

The bot is for an in-class competition. There's no other schools / places competing, its just to show what we learned and stuff throughout the course. There's nothing extra at all.

The bots just supposed to compete in sumo, controlling, an obsticle course (2 of the 3 minimum) and almost everyone is putting a weapon in it, and I want mine to spin. Only one person is working on each bot, thats why they're so small, and it's a one-semester project too. Everything is done by hand, there's no computers involved at all.

Re: New To Robotics
 

That actually sounds like alot of fun. An RC car can be bought for not too much. Then you just need to fix the weapon on top/front/side whatever.

Re: New To Robotics
 

Yeah I suppose that, a few people are taking apart remote control cars like you said.

Just mount the drill and tweak it a bit, but we can't use the actual car itself, we can really only use parts.

Re: New To Robotics
 

I don't want to think RC cars have much torque? Make something with a bit of power and some weight, you'll own the sumo and control competitions.

Re: New To Robotics
 

I basically want to have more spin on the bot than have it moving. So like, move it to a standard speed in the sumo, but have it spin a hella lot faster than its moving.

Re: New To Robotics
 

You may want to check out http://robotroom.com this guy competes and runs mini-sumo competitions in the seattle area I think. His site and books have alot of very useful information for building these robotcs completely from scratch

Re: New To Robotics
 

As far as making it wireless you should look into hobby controllers

http://www.futaba-rc.com/radios/futj63.html

I have that one and iv been pretty happy with it. It comes with a receiver and batterpack. If you dont know already the receiver will out put PWM (Pulse width modulation) that will control speed controllers that will controller your motors (you can also hook a servo up directy into the receiver)

Good Luck!

Re: New To Robotics
 

If you want a high speed, yet fairly light and small weapon, May I suggest going for a cordless dremel? It's simple to wire one to a speed controller or other power source, and they also come with some nice blade choices, like zip cutters and small endmills.

As far as a driving system, I'd go with a vex tank tread kit, as it's not too expensive, yet it still has decent tourque and grip, as well as the fact that it's more maneuverable than a normal rc car (tank style turning).

Re: New To Robotics
 

I"m sorry but again I am new, and I don't really know the parts.

Only thing I know how to control something with is a potentiometer...

Re: New To Robotics
 

You have the power of the internet -- and all semester. Go learn ;)

Re: New To Robotics
 

If the purpose of this project is to build something with the information you are learning, then they may not allow you to use Radio Control systems from RC cars, or VEX controllers. They may require you to use pots and wires to power the motors

you could still have something like a tank turrent spinning on your robot, if there is a non-spinning surface on the top for the control wires to exit the vehicle upwards.

BTW: For Sumo cars (competition where the car at the center of the table after 1 minute is the winner) fast is better than slow and torque-y. When two sumo cars are in a pushing match there is only so much force (energy) at your disposal. But if your car flys across the table and smacks the other one, it will send it flying (impact and momentum). Usually it will knock the other car right off the table.

Re: New To Robotics
 

Just for clarity- This website is the unoffical discussion forum for the FIRST robotics compeition. It is a highschool level international oganization that seeks to promote science and technology. As such, most of the expertise here centers around that, although you'll also find some very, very smart people here from all fields. People such as your self stumble on this site all the time looking for help on problems not directly related to FIRST, and will at least get pointed in the right direction. Certaintly, during the off season we all welcome a chance to help someone. So, Welcome. I hope you keep coming back.

If that is the case, forget about a weapon. Don't even worry your self about it. Focus all your attention on developing a working and powerful (relatively speaking) drive train and control system. Then consider 'up armoring' it. Keep in mind that any of the weapons likely to be carried will not be terribly powerful. There isn't room or electrical power for a real novice to get anything really destructive working.

Turtle up. Get a drive system that will run all day with out breaking, is easy for you to control and provides you with an agreeable ratio of torque and speed. Armor it to the point that BB gun can't damage it and it will survive you kicking it across the floor. Then practice. The more time you have to run it the more you will know what will break, what it's limitations are and how to best control it. Experience in FIRST has shown time and time again that driver skill is at least important, if not more so, then the features of the actual machine.

If it is legal, I would second the purchase of a Vex starter kit. It is something of an erector set for robotics. It will start you off with some basic hardware, a powerful control system and a basic set of ideas for making moving robots. You can then proceed from there with things like more powerful motors, armor, treads and so on.

If it is not legal, and you really do have to create your own kit, then it sounds like you already know the basics of creating a circuit and are not in so bad a situation. Consider controlling a robot using 'tank' steering by switching power and direction of each side of the robots drive system using simple switches in your hand with a tether to the 'bot. This is the simplest and fastest way of getting something working. You can elaborate on this by including things like potentiometers to introduce some speed control.

I am curious. You said that everything had to be hand made. What sort of manufacturing tools do you have? Do you have simple hand tools? A drill? Drill press? Lathe? What sort of materials are you going to use? What your capabilities, and budget, may have a very large impact on the advice you get here and elsewhere. Make sure you are clear on what you can and are willing to spend on this. Robotics can really burn through your spare cash.

There are a number of excellent books on amateur robotics available at any decent bookstore, and probably libraries. I highly suggest you look into them, as they can go into much more detail then we can here.

-Andy A.

Re: New To Robotics
 

To Ken:

We are allowed to use anything that is 'relatively' safe (like no flame throwers, explosions etc). When I have the weapon spinning fast enough, I want the other just to repel off. Pretty much more work on the weapon than the bot itself.

To Andy:

Thegathering suggested I come here for help. This is a really good place :). I don't really have money to buy books atm (no job...just lost it) - so I was suggested to come here. :)

My teacher has a lot of the supplies and stuff. We'll probably have to buy extras ourselves. I was at a store earlier checking stuff out and I mentioned that potentiometer stuff too. That's pretty much what I'll be using haha...

My teacher suggested the same thing. Get hte bot working first then worry about the rest.

Re: New To Robotics
 

Okay here's another question.

If I take apart a remote-controlled car and I want to put a weapon on it (a saw), and the car is wireless, how do I do it, as in how would I make the weapon wireless?

Re: New To Robotics
 

RC cars are a pain to work with as they are proprietary and rarely have access to anything other than what they are intended to do, for this all you will have is 1 motor controller for the drive and 1 servo type controller for the steering(this may be a motor controller it just depends). The RC car will allow you to control 2 motors in 2 directions and that is pretty much it. just wire your "weapon" to one of the motor outputs.

Re: New To Robotics
 

I am a high school shop teacher from Vancouver, BC. A project very similar to what you described was developed by a teacher out here in New Westminster, and we duplicated the playing field at our school for use in a metalwork project. It is a great project.

The reason the tethers are such a brilliant idea is that they allow the robot to be built without a battery on board. If you go wireless you are on the hook for the cost of a battery... a good NiMh seven or eight cell battery will set you back fifteen or twenty bucks at least. The tethers are also a great idea because you can control the robot using mechanical switches... if you go wireless you need to have on board circuitry. Typically this is done using H-bridge speed controllers... which while not AS costly as they once were, they certainly are going to be an expense.

My advice would be to attack this project in two steps... first, build a tethered 'bot that meets the requirements for your class. Then look at how to go wireless.

So far the absolute cheapest way to build a wireless mini-sumo robot (10cm x 10cm x 500g) that I have found is to use infra-red remote control. A PIC 16f627a microcontroller (about $3), combined with an L293D motor driver chip (about $2) can drive a Tamiya dual motor gearbox (about $10 in bulk). Hook up a PNA4602M IR receiver (about $2) and program the PIC to receive the IR signal (the Sony IR protocol is quite easy to learn) and use any Sony or Multibrand TV remote control. It's not Radio Control... but it is wireless. Unfortunately I do not have a ready-made means to scale this up to the size and power you require... so I'd suggest build your first robot to run on the tether... then look at developing wireless control later, perhaps on a smaller machine.

You may also want to consider discussing FIRST and VEX with your teacher, or consider other competitions such as the Skills Canada Robotics competition.

Good luck with the project,

Jason