The Bot Building Overview!
This how to section is done in steps. The order in which this team believe a bot should be done to be successful and not waste precious time or money.
Step 1: Choose a basic design and weight class. Do you want to build a spinner, a wedge, a lifting arm bot, or maybe something completely new. It is important to know what you plan to do before you do it.
Step 2: Research other close designs and Battlebots overall. You need to know what you are getting into and make sure you have the knowledge you need before you begin. Any number of sites have great specific information, and this site has tried to post a pretty good overall review. Try looking at the site of the bot that gave you your inspiration.
Step 3: Begin your purchases. Once you have figured out all that you need to get, start buying. The following is the order in which we recommend purchases. Remember, don't buy anything until you have finished this list. Certain parts may not work with others.
First, get the expensive stuff out of the way. One guaranteed required part that will be at least fairly expensive is the radio. We recommend a Tower Hobbies 6 Channel FM or better, although any 4 channel FM should be competion legal. Many people invest the big bucks in a nice PCM radio. (that's Pulse Code Modulation, as opposed to FM, Frequency modulation.) A PCM is computerized and you could program only one radio to control several bots, but you probably do not have the money for one, I know we didn't. Expect to spend about $130 here for a good 6 channel FM, you won't regret it. Remember, its important to look for a "Futaba" radio or one with Futaba leads. While other radios work fine, most electronic parts are maximized for Futaba leads. All Team Delta electronics can be ordered with Futaba leads already attached.
Second, an also 100% necessary part, the speed control. This can be the most expensive part on your bot, or far cheaper. We very much recommend a Vantec Speed controller here, like the fantastic RDFR23, for about $280. This controller is the best. Full digital channel mixing (which means you get optimal handling) for 2 channels. Remember, a heavier bot may have motors which draw more amps. If your motors draw to many, you may burn out your controller. If you are worried about this or think this is a possibility (SuperHeavyweights or Heavyweights designed for pushing should be worried) then invest in a 4QD. These do pretty much exactly the same thing, except the 4QD can handle higher amperage. If this is beyond your price range, you may choose to purchase 2 directional relays instead. Team Delta sells some very nice relays for this purpose. But these will not provide the nice easy driving of a single speed control, and your driving may suffer. Some people also use single reversible electronic speed controls. This is a little more expensive than the H-Bridges available from Team Delta, but may provide a little better control. The advantage to these is that while Vantecs and H-Bridges can be fitted with some brands of connectors for your receiver, these are available in all brands. If you can buy a radio of a specific brand, you can get a speed control of this type to go with it. However, once again, you must be careful with heavier bots here, so you don't overdraw. Only as a last resort should you look into the other option, mechanical speed controls. If you have ever bought a cheaper remote control car or kit (not like a little kids one, but a base model) you probably received one of these with it. It is distinguished by its large top copper connecector.These are slower to react, have moving parts that can be affected, loose significantly more power than an electronic, and prove more difficult to mount since there is a servo involved. The only possible advantage is that these is that they can handle just slightly more power draw than some electronic speed controls. This of course changes somewhat if you want servo steering as opposed to tank style.
Next, you need to select drive motors. These are different for everybody. In our case speed was not important, but power was, and we just happened to find the perfect motors for us. Certain sites may say you need this motor or that motor, but that's just not true. First you have to understand motors. An electric motor takes and electric current and switches electromagnets on and off to rotate a shaft. There are two types AC and DC, you will only want to look at DC (direct current) motors. Motors will most often have a few notations by them. The first to look at is torque. This will be given in a length to weight ratio. Maybe oz/in (that's how many ounces the motor could lift on the end of an inch long bar). Or maybe in/lbs, Newton/meters, or even ft/lbs. What you want in this respect varies on the type of bot. A good standard lightweight might have 50 in/lbs of torque. A middle weight be 150 in/lbs, heavy 10 ft/lbs, Super heavy 20 ft/lbs. The second number is RPM (revolutions per minute). This varies in requirement with design. For instance, a Blade Runner type design may be willing to sacrifice some power for speed so that its hits will come faster, thus harder. However, a Punjar type design would want more power to push its opponents around. A good average would be about 150 RPM. If you can't find perfect motors to fit your purposes, remember you can always gear them different. In fact, even if your motors are perfect, you should at least run them through a single gear to help protect them. This can be avoided by buying gear head motors, which are already mounted with gears. If you do need to gear, a bigger gear on the motor and a smaller gear on the drive will make you go faster, while the reverse will add tourqe. This all changes if you are building a walker however, but I won't go into that. Pricing on motors varies much depending. Just remember to bargain shop. Often you can find a motor the same or better than the ones you thought you first wanted for cheaper.
Also a guaranteed part, but far cheaper, are the batteries. The only type worth using (and pretty much the only type legal) are sealed lead acid, sometimes called Gel Cells. This means that they are completely sealed and the acid inside is in a jelly like state, thus making it less likely that they will leak. More than likely, you will want to look at 12 Volt batteries. When choosing a battery, it is important to judge weather or not they will have enough amp hours. Just guess on this, and test if you need more power later. You may decide that you would like to run 24 volts instead of 12. If you bought 12 volt batteries, this can be accomplished by running them in a series, positive to negative terminal connections are used for this. Or, you may decide to run in parallel, which will double your amperes. This is a positive to positive, negative to negative terminal connection. Powersonic Hawkers are a good choice. We personally went with Mendelson Electronics 12 Volt 5 ampere batteries. Remember to purchase at least double the amount your bot will be using, so you can leave the other set charge while you are battling. And also, remember to get chargers. These should be between .5 and 1.5 amperes, depending on your own batteries.
Next, you might say, finally, I get to the weapons section, but this is not so. The next thing necessary is metal. This is absolutely essential as a wooden bot would just suck. You will definitely need metal for your internal components and frame, though you may choose to go with something else for armor (lexan, or others, such Kevlar, which Blade Runner uses). Your frame pieces need to be strong enough to hold all your parts in place under a severe amount of punishment. It may be wise to construct a metal holding device for your electronics, to help keep them protected incase of an armor puncture. A good solid thickness of aluminum plate will probably do you fine for a light or middleweight. Heavies and Superheavies may want to incorporate some steel on the higher stress points. You'll also need metal, in the form of a round piece, for any type of drive shaft. This may be accomplished with something as simple as a big, thick bolt, or may be a specially machined work of art. Other metals may be necessary, only you know what your bot is like, unless you post it like ours (by the way, don't steal the design, its still untested, so even we don't know, maybe it sucks). One thing to remember. Radio signals will not travel well though metal, if at all. If you are using Lexan or other types of armor you should be fine. If using metal, you will either need to mount an external antenna or make some sort of custom design incorporating other elements (I won't tell you what we did). Metal can be ordered from a variety of sources, but more than likely, basic sheet can be found around the house or a junkyard. As for me, I was lucky to have a dad in the scrap metal trading business (Can you say virtually no metal purchasing) :)
Almost to the fun part, but not quite. Next I recommend wheels. These are the last essential part to completing a bot. These should have good grip, be durable, and be big enough to touch the ground on at least the bottom of your bot. These may be set internally or externally, and be any range of shapes sizes and types. You may only need little wheels to run the bottom of your bot, or big wheels to make your bot invertible. You may want only two, or lots (War Machine has 10). As for type, as I said, just grippy and durable. You all have probably seen what happened to Tentomushi fighting Evil Fish Tank in season 2. That is what happens when you have no grip. If I had to recommend a type, I'd say Colson caster wheels. These are hard rubber wheels with Tough plastic centers. The rubber on these things is great. These are so grippy they feel sticky just to the touch. I can't say anything about durability yet, but lots of others have fielded them successfully. Colsons are available from Team Delta or other places if you know where to look.
Hey! Look at that!! Your bot is now drivable. If you are building a stricly pusher or wedge or Blade Runner style design, you are probably done!! YAY!!! If not, Fun Resides Ahead!!!
If you only ordered a 2 channel radio at this point, you are SOL (So outta luck) as you used up both channels making your bot drivable. Didn't I tell you to wait! Oh well, we'll hope that didn't happen. There are many types of weapons out there. You may have chosen from one of the previously proven weapon designs, just trying to improve upon it, or invented something new. If you put no imagination into your bot and strictly coppied another design, not bothering to improve or change it, then I'm sorry I helped you. You should really try harder at doing something new or better. Once again, we'll hope that didn't happen and move on. There are a few mandatory parts for a weapon and they are as follows.
1. An open radio channel.
2. Some way to switch your weapon on and off (a relay perhaps).
3. A weapon power system.
4. Strong metal for the parts of your weapon that physically affect the opponents bot.
The first point was addressed earlier. The second comes second, as is to be expected. All weapons, no matter what, must be off at the start and finish of a match. To start and shut down your bot's weapon, you'll probably want a relay, unless it is a liquid fuel powered weapon, in which case you'll want a servo to adjust the throttle. Assuming it is not liquid fuel based, a strictly on/off relay is probably the way to go. You will probably only need a single direction relay, as your weapon is probably most effective in one direction. Team Delta relays come with a good instructional paper telling you how to rig it up properly. The only way you'd want a 2 directional relay is for a lifting arm, so you'll have a way to return it to starting position. Team Deltas H-Bridge shows how to rig it up to power a linear actuator. Remember, your weapon, if an electric motor, probably draws quite a few amps, so you will want to use your relay to switch on a higher power relay device, such as a solenoid, which can take the extra draw without burning out. If your weapon is pneumatic in nature, where you only need to open and close a valve, just a relay should be sufficient.
The next, a weapon power system is the fun part. This is where you look for the strongest, fastest motor, engine, actuator or other power source you can find. The need varies weapon to weapon. A spinning weapon requires a fast motor or engine. A lifting arm requires a linear actuator or pneumatic cylinder (although there are ways to do this with a high power, very slow motor, but I wouldn't recommend it). An over the top arm can be done with pneumatics (deadblow) or a motor (frenzy). A flipper arm (Toro) or crushing jaws pretty much must be done with pneumatics. As stated previously. Just go to the site of the bot or a like bot that gave you your inspiration, and you should be able to find out what sort of power system you need.
Finally, the metal that will be used to make your weapon. This, more than likely, has to be the strongest part of your bot. The shafts, bars, or other support and drive mechanisms of your weapon will take more abuse than anything. This will be where you will waste the most weight making things thick enough to be strong. A disk such as Nightmare's takes a tremendous amount of force every time it hits an opponent. That is why it is the thickest part of his bot. Likewise, his motor seating for that must be very strong, to help prevent shifting. The South Bay Robo-Warriors probably thought Mauler's weapon was more than well enough attached until it went flying off during the 2000 LV season. Also, depending on your weapon design, the rest of your frame may need to be bulked up to. A lifter or flipper will need a stronger frame to support the weight of a second bot. A wheel-powered spinner will need a stronger portion of arm length and connections to attach it. I believe we all saw Mijolner fight Vlad last season. The best way to save weight on these thicker parts is to mill out holes. These may remove more weight than you'd think without sacrificing much in strength.
Calculating speed is easy: First find the circumference of your wheels, either by measuring or the simpler equation: Diameter * Pi. (Diameter is the distance from one side of a circle to another through the center to the other. 3.14 can be substituted for Pi if your calculator doesn't have a Pi button.) That is how many inches you travel in one rotation of your wheel. Next, multiply that by RPM to find your maximum inches traveled per minute. Multiply that by 60 to find inches per hour. Divide by 12, feet per hour. Divide by 5280, Miles per hour. With any luck you are between 5 and 15. That will probably be enough for any bot.
If you don't mind not knowing exact specifications on your motors, you can get them somewhat cheaper off of power window or wiper systems from the junkyard.
Take your time. Usually those are the bots that do the best. Stephen Felk spent three years building Voltronic, and he made the finals right away.
Very rarely is there a specific brand or part you absolutely need. Despite what people say, usually there is at least 1 other alternative.
Do what you know. Frenzy's creator knew advance mechanical-electronics integration and he built all his own boards. You should see the amount of electronics he has just to swing that arm overhead! He installed optical sensors to cut out the motor at the appropriate time so he wouldn't burn out the motor with those hard landings! Yeesh! If ida' done it, mine would have consisted of a high draw relay and some…wait, that's all. So if you know advanced machining, then create some work of art specialties to put in your bot. If you know finances, do it cheaper than anyone thought possible. Maybe the only thing you're good at is writing or drawing. Well, think of some choice words or a piece of art to post somewhere that will put the fear of god into your opponents. Almost every skill is usable somehow. Even something like knitting could be used to make custom team sweaters. See, really any skill can be used somehow (although its probably easier just to get a T-Shirt screen printed).
The last piece of advice, Be Imaginative! There is always something new to be done or improved. Never just copy or do something completely blah. All right, I'm through preaching now. If you have any more questions, feel free to contact me.