Q: How do I search this page? The search box got me this far.

A: Use the search function in your browser to search a specific page: hit CTRL-F to bring up a page search box.

A: I count 28 north american tournaments in 2007. Events were held in 11 U.S. states and Canada. There are also regularly scheduled robot combat tournaments in the U.K., Australia, and Brazil. Just because they aren't on TV doesn't mean they don't exist. Get out and participate!

A: Check the Robot Fighting League Events Calendar and the Builders Database for events in the US and Canada. For British events, try The Fighting Robot Association.

A: Take a look at the Wikipedia article on Robot Combat for a good summary of the subject.

A: There's way too much to cover here! Support your local public library -- there are some great books on building robots. Look on the shelves in section 629.892 for a good selection. You can check our Book Review Page for some specific recommendations.

• You can get a step-by-step construction lesson from the 'Build a Robot' page at coolrobots.com.
• Take a look at the Toy Hacks and Kits section of the archive to get some more ideas.

A: We're happy to answer specific questions about robot design, construction, and materials, but we're not here to design your robot for you.

• Answers to generic design questions, and tools to help with other design considerations can be found in the Ask Aaron Archives.
• Do your homework, read thru the archives, and come back with specific questions that haven't already been answered here.
• We need enough information about your design and requirements to have some shot at a useful answer.

A: Start out small -- it's a lot less expensive to learn from mistakes you make on a 12 pound robot than on a 220 pound monster. Study their rules, watch a live competition, learn what you can from the internet, and ask specific questions of the builders. Check out the library and bookstores for help on building robots, too. Amazon.com has lots of robot books.

A: Robot builders design and build 'bots all different ways. Some use computer drawing software to design every last detail before they buy parts. Some build exact models from cardboard to see how things fit. Some just buy lots of parts and see if they can fit them together like a jigsaw puzzle. I like to list all the parts I think I'll need, sketch a drawing, and add up the weights of the parts to make sure I'm under the weight limit. If you stick with proven parts that other builders use, you won't get into too much trouble.

A: You're going to spend a lot of time and effort building your 'bot and going to a tournament. When some component fails in combat and puts you out of the competition, you're gonna wish you hadn't gone cheap. In particular, don't scrimp on electronics! With experience you'll learn where you can save money, but it's not gonna be on key components like speed controllers and wheel hubs.

A: A good place to start is robotmarketplace.com. If you can't find it there, you probably don't need it. Other sources:

A: If there was one type of weapon that was 'best', everyone would be using it. Although the highest ranked combat robots generally use high-powered spinning weapons, those teams are very experienced builders. Overall, you might be surprised by what weapons win the most matches.

How does [insert flamebot name here]'s flame weapon work?

A: You can search the archive for 'flame' to find our many previous posts on flame weapons. To summarize:

1. Flame weapons are ineffective in any weight class.

2. Flame weapons are built by very experienced builders who just want to show off.

3. We will not discuss flame weapon construction here because we don't want novice builders hurting themselves.

4. By the time you are experienced enough to safely build a flame weapon you won't need to ask me how to do it.

5. That flamebot that you're about to tell me is successful was built by a very experienced and well financed team and would be just as successful without the flame weapon.

A: Check the current Robot Fighting League rules for details on allowable weapons.

A: See our Armor Guide.

A: Very briefly, with a number of assumptions:

• The power input pads for drive ESC, weapon ESC, and power indicator light connect in parallel to the battery via a plug so you can disconnect the battery to charge it. Get the polarity correct! If you want to add a charging plug, see the charging jack post.
• Drive motors connect to the motor output tabs on the drive ESC -- weapon motor to the power output tabs on the weapon ESC.
• Two three-wire R/C input cables attach to the drive ESC signal inputs, and one R/C cable for the weapon ESC. They may already be attached. If not, double check the correct connection of the three wires (power+, power-, and signal) -- if you get it wrong you'll fry something.
• Drive ESC R/C cables plug into whichever channel ports you'll be using on the receiver: typically 1 and 2 if you're mixing, 2 and 3 if you're not. The weapon ESC R/C cable plugs into a spare channel of your choice.
• The crystals for receiver and transmitter are different -- plug the correct crystals into the receiver and transmitter

A: My best robot tip is to make sure the basics of the chassis and drivetrain are really well built. I see lots of 'bots lose matches because something really simple wasn't designed well: wheels fall off, battery packs break free, unsecured wires come loose. The most insane weapon is no use at all if the chassis or drive fails.

A: Radio System Requirements from the RFL 2008 Rules.
Check with the event organizer for any variation in these requirements.

Robots with passive weapons	Minimum Radio Requirement	Fail-Safe Required
		Drivetrain	Weapon
1 pound & under	AM or Toy OK	NO	---
3 and 6 pound	AM or Toy OK	NO	---
Hobbyweight	AM or Toy OK	NO	---
30 pound & up	Coded FM or Digital 900 MHz/2.4 GHz Required	YES	---

Robots with active weapons	Minimum Radio Requirement	Fail-Safe Required
		Drivetrain	Weapon
1 pound & under	FM Required	NO	YES
3 and 6 pound	FM Required	YES	YES
Hobbyweight	Coded FM or Digital 900 MHz/2.4 GHz Required	YES	YES
30 pound & up	Coded FM or Digital 900 MHz/2.4 GHz Required	YES	YES

A: A brushed permanent magnet direct current (PMDC) motor has a rotating 'armature' of wire coils, typically wound around iron pole cores. The armature is positioned in a field generated by stationary permanent magnets. Electrical power is transferred to and correctly switched between the armature windings as they rotate by stationary brushes pressing against a set of contacts on the armature (the 'commutator'). There is a good diagram at Wikipedia: DC Motors. The brushes sliding across the commutator create friction, wear, and inefficiency.

A brushless PMDC motor has stationary wire coils and rotating permanent magnets. Since the coils are stationary, sliding brushes and commutator are not required -- however, the switching of electrical power to the correct coil windings must be handled by an 'intelligent' motor controller that senses the position of the rotating permanent magnet field. If the rotating magnets are outside the wire coils, the motor is an 'outrunner' or 'rotating can' design. If the rotating magnets are surrounded by the wire coils, it is called an 'inrunner'.

A: Speed controllers for brushed and brushless motors are very different in design and cannot be interchanged.

A: All the tools you need to evaluate spinner weapons and motors can be found in the archives. There's a ton of information about weapon motor selection in the archive, and a metric buttload of answers to weapon design questions in the archive. In particular, the Team Run Amok Spinning Weapon Excel Spreadsheet will detail and graph the performance of specific motor/weapon pairings.

A: It is common practice in combat robotics to run weapon and drive motors at higher voltages than they are rated in order to obtain greater power. How far a motor can be overvolted depends in part on how much load is placed on it. If allowed to bog down close to stall, an overvolted motor will not survive long. Better results will be obtained by setting up gearing and wheel diameter so the motor can provide enough torque to spin the wheels before it slows below about half the free RPM of the motor. The Team Tentacle Torque & Amp-Hour Calculator can help you select wheel sizes that will keep the amp load reasonable at elevated voltages.

Also, be aware that high performance airplane motors are already being stretched about as far as they can go on voltage, while motors from industrial equipment will usually take a large voltage increase in stride.

A. Check out our Beginners Guide to Combat Robot Gyros.

A: Pretty much everybody has or had websites. Here's my trick:

1. Go to the RobotCombat.com Links Page and click on the link to the team you want. Click 'U.K. Robots' at the top of the page to list British teams.

2. If the site no longer exists or no longer has robot info, copy the URL and go to The Wayback Machine.

3. Paste the URL into the search box and hit the 'Take Me Back' button.

4. You'll get a dated list of archived 'snapshots' for that site you can click up.

A: Questions from the 'Ask Aaron' website used to all come from the same webmail server address. If they weren't signed we could only guess at who wrote them and we may not have known that a question was linked to an earlier discussion. Recently we switched to a different webmail system and we should be able to track this better. Remember, our psychic abilities are weak so please give us enough information to at least have a shot at answering your questions.

A: I'll replace it when I win a bigger trophy.

A: Just send it in thru the website and mark it 'CONFIDENTIAL'. I'll keep it between us.

A: The Team Run Amok video library contains recordings of every nationally televised combat robot event. We respect and honor the rights of the copyright holder for these programs. We will not place copywritten video on the internet and we do not support the efforts of those that do.

A: Mark J. here: I get this same question, word for word, several times a year. Could you slackers at least re-word your class assignment before you send it in to us?

The behavior is classic approach / avoidance -- the robot will effectively 'lock up' and do nothing. The common solution adopted in sumo robots is to lock out the edge detection routines whenever the object detectors report you're heading toward your opponent.

Your Robocup robot can use a similar strategy: if the red ball is in your path, override the blue wall avoidance routine AND move toward the ball. A more sophisticated approach would utilize an elevated video camera looking down on the field to verify the relative positions of the wall and ball and determine action accordingly.