First Robot - School Project - Robot Wars

[codestar]

Hello Everyone,

I am new to this community, and I would greatly appreciate some help on making my first robot. Well I say it's my first one. I've made some bristle bots, and beetle bots.

Well, my school is having a small robot war, and I'm participating..
I've drew up a simple schematic on paint.. Mainly to show the basic idea...

First, I want to explain what I would like to have on my robot. I want a robot that will move forward, backward, left turn, and right turn. I also want a set of turning "blades" on the back.

What I have.. I have my schematic set-up to where my robot can go forward, left turn, and right turn. I also have the blades set-up. It drives forward by flipping the switch for both motors. The motors are 12 to 18 V DC. I plan to power each motor by the following battery set:2sets of 9 V batteries in series and connecting those sets in parallel. So for the two main motors, I will be using 8 9V batteries. It turn by simple flipping the switch for only one motor. I have the blades set up on some motor, not sure of specification yet, but I plan to run it on a 9V battery as well.

What I need to know.. I need to know of ways to allow it to reverse. I also need to know how I should go about constructing it, in other words, is there an easier circuit to make? I didn't know if I should use any IC's or if there are any parts to make it easier to control or w/e... I also need to know how to give the commands, The only thing I know to do is wire it to a 'controller' of switches. I don't know how to go about this at all. I would like to make it wireless too.

Here's the schematic:


I also want to include a small turbo, that I will have powered by a 9.7 volt battery, in series with both of the power supplies, that way I can give a little extra push if I need to.

All tips, hints, ideas, and criticism accepted!

Thanks,
~Cody

P.S. I would also like to know where I could get cheap products, such as batteries, components, rc supplies for the robot.. I currently use Electronic Goldmine, and looking at Futurlec.com .. Haven't bought from them yet, any reviews? Other suggestions?

[rbtying]

I can't say much for battle robots, having  never built one myself, but I can guarantee your current design will barely move.  9V batteries can't provide nearly enough current for what you want - you should use at least AA batteries in series to get your high voltage, OR a battery pack.

[codestar]

Sorry, I don't understand, if I were to put two nine V batteries in series, it would give me 18V, how is that not enough for a 12-18V motor?

[waltr]

The battery voltage is not the only quantity that determines its usefulness.
How much current (Amps) the battery will deliver and the battery's capacity (Amp-Hours, how long will the battery deliver the rated current) are two very important specs. Another is the battery's chemistry, NiCd, NiMH, LiIon, LiPo, Lead Acid, etc. Knowing the chemistry is important for several reasons one of which is how to properly and safely charge the battery. Are the batteries re-chargeable.

What rbtying is saying is a 9 V, typically a small 'transistor', battery will die in a matter of minutes to seconds if connected to a motor. And even while it is still charged (alive), it will not put out enough current for the motor to have power (torque).

Look up batteries first in the SoR tutorials and then google for more details.

Give us more info on the battery you plan to use. A link to the specs is very helpful.

The next piece is the specs on the motors. Again Voltage is not the only criteria. Nominal current draw, stall current, stall torque, and RPM are all interdependent quantities of a motor and also interact with the battery specs.

Also, what will the Bot weight? The heaver the Bot the stronger the motors need to be which will draw more current from the batteries which drain the batteries quicker. So work this out. The SoR tutorials also have info on calculating this.
 

I need to know of ways to allow it to reverse.

There are ways to wire a switch to allow reversing the motors. Look up DPDT reversing switch in google.

[Redcap]

Team Orr posted some links late last year which may be of some use to you.
The reverse triggers are shown in the 3rd video.
There are much better ways to do it (as this example is either on or off, no speed control), but it at least gives a starting point of sorts.

How to build a combat robot pt 1

How to build a combat robot pt.2

How to build a combat robot part 3

[Fr0stAngel]

If you have a little time in hands, you better give a try to learn to use micro-controllers. Because they are a much better and efficient way to do what you are planning to do.
And also the fact that sooner or later you will have to learn to use them in robot building, so...why not stat now?

I strongly recommend that you check out the tutorials here at SoR.
try this for starters http://www.societyofrobots.com/robot_tutorial.shtml
Go0D luck with your robot..!

[codestar]

Thanks, everyone, I'll check out all the posts. I'll also add additional information on my motors.