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The antweight division in combat robotics features constant action where small robots weighing 1 pound (150 grams) or less engage in fast-paced battles. With weight-stingy antweights, every detail of the robot’s design, from weaponry to drive train, plays a critical role in a robot’s performance. One such crucial factor is the motor. The motor size, or more specifically, the type of motors used and their specifications, can make or break a robot’s ability to perform efficiently.

In this blog, I’ll dive into the importance of motor sizes in antweights and how to choose the right motor for your robot.

The Role of Motors in Combat Robotics

Motors are at the heart of every robot’s movement. In combat robots, motors control various aspects of the robot, from driving to weapon systems. These motors determine the speed, torque, and overall power output of the robot, directly affecting its combat effectiveness. Whether it’s a simple drive motor or a powerful weapon motor, choosing the right motor size is essential for building a competitive robot.

Motor Sizes and Types in Antweight Robots

In antweight robots, motors come in various sizes and configurations, each with its unique characteristics. The key factors to consider when choosing a motor are:

1. Speed: The RPM (revolutions per minute) of the motor dictates how fast the robot moves or how quickly the weapon spins. A higher RPM can result in faster speeds and quicker weapon action but may sacrifice torque.

2. Torque: Torque is the rotational force a motor generates, which helps move the robot and power the weapon systems. A motor with high torque is essential for robots that require high pushing power or need to deliver a strong blow from a weapon.

3. Size and Weight: Antweight robots are limited to 1 pound (150 grams) in weight, so the size and weight of the motor must be carefully balanced with the robot’s overall design. Motors that are too large or heavy will reduce the available space and weight for other components.

4. Voltage and Power: The voltage rating of the motor will determine how much power it can handle. Most antweight robots run on 7.4V or 14.8V battery systems, so selecting a motor that operates within these parameters is important for maximizing performance and ensuring safety.

Types of Motors Commonly Used in Antweights

DC Motors

DC (direct current) motors are the type of motor used in antweight robots. They are simple, efficient, and can be easily controlled for both drive and weapon systems. DC motors come in various sizes, with small, lightweight motors typically chosen for their ability to provide high RPM and reasonable torque for their size.

Brushless Motors (BLDC – brushless direct current motor): These motors are increasingly popular in combat robotics because they are more efficient, reliable, and lightweight than brushed motors. They offer a higher power-to-weight ratio and are perfect for antweights, where every gram counts. For rotating weapons like spinners, a brushless motor is the preferred choice due to the high power needed to achieve high rotational speeds. 

Brushed Motors: While brushed motors are older technology, they are still used in the sport. They tend to be less efficient than brushless motors but are often cheaper and easier to control. While some antweight robots may still use brushed motors for driving, brushless options are gaining traction due to their improved performance. 

Gear Motors

Gear motors combine a motor with a gearbox, reducing the RPM and increasing the torque. These are particularly useful for driving wheels and controlling more powerful weapons. By using a gear motor, you can trade off speed for greater force, which is essential in close combat situations.

Servo Motors

Servo motors are primarily used in robot arms and weapon systems. They allow for precise control of rotation, making them ideal for applications requiring high accuracy, such as a rotating weapon or a lift mechanism. In antweights, servo motors can be used for systems where tight control is needed.

Step Motors

Step motors are generally not used with antweights due to their limitations in power and speed.

Selecting the Right Motor Size for Antweights

When selecting a motor for your antweight design, size does matter—but it’s not just about choosing the smallest motor possible. It’s about balancing motor characteristics to meet the specific needs of your robot. Here’s a basic guideline for motor selection:

For Drive Motors: Antweight robots typically use motors that provide a balance between speed and torque. If you are building a robot with high mobility and agility, opt for a small, lightweight motor with a higher RPM. Conversely, if your robot focuses on pushing or ramming, prioritize a motor with higher torque and lower RPM.

For Weapon Motors: If your robot features a spinner or other high-speed weapon, choosing a motor with high RPM and sufficient torque is essential. Brushless motors are generally preferred for weapon systems due to their higher efficiency and durability. Be sure to select a motor that can withstand the intense demands of weapon action, often requiring quick starts and stops.

Weight Considerations: In antweight robots, the motor should take up as little space as possible while still providing adequate performance. Excess weight in motors can reduce the weight allowance for other components like armor or weaponry. A well-chosen motor should be as compact as possible without compromising on necessary performance.

Motor Efficiency and Battery Life

Motor efficiency plays a critical role in maximizing battery life. Efficient motors use less power for the same output, meaning you can get more combat time per battery charge. In antweight combat robotics, where each second counts, efficient motors can give you the upper hand in longer fights.

Battery life is also tied to motor performance. More powerful motors may drain your battery faster, which could leave you vulnerable towards the end of a match. Therefore, it’s important to strike a balance between motor power, speed, and energy consumption.

*Check out my Knowledge Base Article Which Battery Should You Need*

Conclusion

In antweight combat robotics, motor selection is one of the most important factors determining your robot’s performance. The size, type, and specifications of the motors directly impact everything from speed to weapon power and control. Whether you’re building a nimble, quick robot for agility or a powerful bot with a strong weapon, understanding motor sizes and how they fit into your design will give you a competitive edge in the arena.

Remember, every robot is different, and the key to success is finding the perfect motor combination for your unique needs. Experiment with different motors, gear ratios, and configurations, and you’ll find the sweet spot for your antweight combat robot. Happy building and battling!

Click here for more robotics blog posts

Check out my collection of Knowledge Base Articles for more robotic info.

If you are new to combat robotics, or even a seasoned veteran of many tournaments, information is crucial to becoming a better builder and competitor. Luckily for fighting robot enthusiasts, there is a ton of information available the Internet. Here are just a few of the websites and groups with great combat robotics information.

The Big Boys (and Girls)

It started for most of us when we first saw robot fighting on television with either Robot Wars or BattleBots. We were hooked with the first shower of sparks. Even though those shows featured huge bots costing thousands of dollars to build, there is still a lot of information for those of us competing at the lower weight categories.

BattleBots Official Website: The official site for the popular television competition features team profiles, event schedules, match results, and behind-the-scenes content.

The BattleBots Robots: A great resource to learn about the teams competing in BattleBots, with links to their social media and websites.

A Community of Combat Robotics Enthusiasts

Reddit – r/battlebots: A subreddit group with over 70,000 members. The group is an independent community for fans of robot combat, not representing any one brand. They welcome those with a casual interest in television shows as well as the enthusiast community.

Hackaday: While not exclusively focused on combat robotics, Hackaday features articles on innovative robot designs, tutorials, and projects that can be relevant to combat robotics builders.

Instructables: This site has many user-generated tutorials on building combat robots, covering various designs and techniques.

Facebook Groups

Various groups exist for combat robotics enthusiasts, where members share insights, event information, and offer support to each other. Do a search on Facebook and you will find a bunch of them. Here are just a few: (member numbers data as of 1/23/25)

Robot Weight Class Groups

• Antweight Combat Robots (5 K members)
• Plastic antweight combat robotics group (607 members)
• Beetleweight Robot Combat (5.5K members)
• Featherweight Robot Combat (532 members)

Regional Groups

• Texas Robot Combat (1.2K members)
• Arizona Robotic Combat (ARC) (825 members)
• Florida Combat Robot Builders (403 members)
• Combat Robots of Oklahoma (622 members)
• Ohio Robotics Club (823 members)
• Michigan Combat Robotics (248 members)
• Utah Combat Robotics Group (277 members)
• Carolina Combat Robots (413 members)
• Colorado Combat Robotics Club (961 members)

Other

• 3D Printing for Robot Combat (3.0K members)
• Combat Robot Flea Market (2.5K members)
• Beater Bar Combat Robot Builders (629 members)
• BattleBots Fans (10.8K members)

YouTube Channels

YouTube is a great resource for combat robotics. There are dozens of channels dedicated specifically to combat robotics, including channels from individual builders, teams, commentators, and dedicated news platforms covering the sport and its related events. Here is a small sampling of what is available:

Ray Billings team captain of Hardcore Robotics, and the builder/designer of the BattleBots champion robot Tombstone! This channel focuses on various robotics projects along with some building and competing guidelines. (56K subscribers•177 videos)

Team Witch Doctor Those familiar with BattleBots will associate the name with the hugely successful vertical spinner bot with the ribcage design as armor. The channel includes a “Witch Doctor Junior”playlist with team member Andrea Gellatly covering everything you need to know to build and compete an antwaight. (17K subscribers•294 videos)

Robert Cowan Member of Team Copperhead of BattleBots. The channel covers CNC, robotics, various other projects. The channel has many great combat robotics videos, including a playlist of videos about building an antweight Combat Robot. (66.5K subscribers•392 videos)

Team Just ‘Cuz Robotics Seth Schaffer is a Mechanical Engineer with a passion for combat robotics. The channel is dedicated to sharing the knowledge needed to build combat robots and other related DIY projects. He is also a member of the Battlebots team behind the vicious overhead spinner Bloodsport. (10.3K subscribers•225 videos)

Team Panic Channel of an electrical engineer with an interest in robot combat. His videos document his experiences with build logs, tutorials, 3D printing and other robotics stuff! (8.05K subscribers•386 videos)

DrumBotics Welcome to DrumBotics Youtube channel where we will be uploading antweight competition fights updates about our robot and more! (1.4K subscribers•52 videos)

Team Cryptid Robotics This channel includes bot builds and guides about combat robotics. He states the goal of the channel is to grow the sport, build hype for his bots and guides for all the things he “wished existed when I got into combat robotics”. (364 subscribers•71 videos)

Other Combat Robotics Resources

Robot Combat Events A listing of combat robotics events in the US.

Ask Aaron Combat Robotics Q&A Team Run Amok started Ask Aaron in March of 2003 to answer the robot combat questions sent to their team. Twenty-one years and 7500 questions later they are still fielding a very broad range of practical, theoretical, arcane, obscure, and sometimes just plain silly questions.

The Robot Combat League A non-profit whose mission is to promote STEM and design and fabrication skills through the sport of Robot Combat. The Robot Combat League is not an official organizing body for Robot Combat.

NHRL Official website of the National Havoc Robot League. The organization is the home of the 3lb, 12lb and 30lb world championships through a series of seven combat robotics tournaments hosted in the House of Havoc. The group is based in Norwalk, CT.

Don’t You (Forget About Me)

Last, but certainly not least, is the robotics section on my Knowledge Base Articles page. As of this writing, I have nine articles on combat robotics, with everything from The Science Behind Robotic Warfare to Sumo Robotics. You can find my Knowledge Base here.

Conclusion

These resources can be invaluable for anyone interested in combat robotics, whether they’re looking to build their own robot, stay updated on competitions, or connect with other enthusiasts in the community. This is just a very small sampling of what is available. Google (or another search engine) is your friend. A search will reveal a wealth of resources.

Have you been thinking about the possibility of getting into combat robotics? If so, this blog post is just for you.

I decided to write this because I’ve talked to several folks lately who said that BattleBots stuff looks really cool, but they wouldn’t even know where to begin. After all, robotics can be some pretty complicated stuff. And it can be, but the robots competing in the lower weight classes (fairweight, antweight, beetleweight) are not terrorabally technical.

You don’t need a degree in electrical engineering to enjoy fighting robots. All you really need is a desire to learn… plus a little cash (or credit).  And even though money could be tight, I think most would be surprised how cheaply you can get into the hobby.

Your Ticket to Fun

There’s basically three ways to get into the sport. You can buy a package with everything you need to get started, all pre-built and ready to rumble. You can buy a kit which includes all the parts needed for a little shredding machine and build it yourself. Or you can design and build your bot from scratch, which is very attractive for some.

So if you are technically-challenged or not, there’s an avenue for anyone to get into the hobby.

Ready to Rumble

The easiest way is to purchase a all-in-one package with a fully built robot and radio transmitter. With just a little practice, you can be competing in local tournaments in no time.

There are several reputable companies selling these kits. Palm Beach Bots is just one offering “ready to fight” packages. They include FingerTech Robotics’ Viper in such a package. They have several other bots with different configurations, from lifters to vertical spinners, that can be made ready to fight with just a few add-ons.

A google search will direct you to other companies offering all-in-one options.

Don’t Forget Spares

Hopefully, whichever kit you purchase, it comes with a few extra parts because you are going to need them. There’s many times in-between matches you will need to repair the damage your bot incurred in the last bout. In some instances you will need to make repairs to be able to continue. Several people in tournaments will bring more than one robot just in case repairs can’t be done.

This leads us to the major disadvantage of buying one of these “everything included” kits. If you haven’t actually built the bot, you may not have the knowledge of the inner workings enough to make repairs. If that’s the case, you are dead in the water.

A Better Option

In my humble opinion, a much better option to the pre-built kits would be a kit that requires you to actually build the bot yourself. This gives you a working knowledge of how your bot works. You will understand every little thing about the workings of the robot, making repairs much easier. 

These kits include all the individual components including a chassis, drive motors, wheels, an electronic speed controller (ESC), a weapon system (if using one), a battery, and all the necessary wiring.

A few kits even include a radio transmitter and receiver. If the kit doesn’t include a radio, you will need to make sure the receiver that comes with the kit is compatible with the radio you have or plan on purchasing.

Check out radios in my shop pages

Once again, if the kit doesn’t come with spare parts, you will need to purchase those separately.

Which Witch to Watch

For those wanting to start this way, I’m going to point you to the YouTube channel of one of the prominent BattleBots teams – Team Witch Doctor.  Those familiar with BattleBots will associate the name with the hugely successful vertical spinner bot with the ribcage design as armor. Team Witch Doctor has not only been successful fighting the big boys in BattleBots, they also have a 501c3 non-profit dedicated to promoting the combat robotics community. They also provide STEM (Science, technology, engineering, and mathematics) programs, enabling young builders outside of the “BattleBox”. In my opinion, that’s super cool!

On the Witch Doctor Youtube channel, look for the “Witch Doctor Junior” playlist. In this series of 9 videos, team member Andrea Gellatly covers everything you need to know to build and compete an antwaight (1 lb).

Andrea walks you through everything from the drive train to competing in your first tournament using the FingerTech Robotics Viper kit mentioned above.

I feel very comfortable recommending these videos as they are one of the most complete build series I have found on the net. You can view the videos here.

For Those That Like A Challenge

A third option would be to design and build the bot from scratch. This would be the choice for all the makers and creators out there. There’s some that get into the hobby just for the challenge of designing and building a combat robot.

Of course, building a fighting robot from scratch can seem pretty intimidating to many. But the bots built for the smaller weight divisions are typically pretty simple. Especially if a less complicated weapon or a wedge is incorporated into the design. More advanced weapon systems can always be added to your bot later when your technical confidence is higher due to more experience. 

The good news for those wanting to get started this way is there is tons of information available with a lot of these resources being totally free if you have an Internet connection. There’s several great websites and YouTube videos with detailed info on building combat robots from scratch. Google (or your favorite search engine) is your friend. But I think I better save that one for a future blog post since this one is getting a little long.

Putting This Post to Bed

In conclusion, not only is fighting bots loads fun, but it’s easy to become part of the growing combat robotics community – no matter your current technical level. Between books and the Internet, you can easily learn everything you need to get involved. And get your friends involved too. There’s no greater satisfaction than total destruction of your best friend’s bot.

You have been mulling the design of a new combat robot for a while. You just know you have the plans for a bot that’s gonna take names and kick some serious butt in your local combat robotics arena.

You’ve made a list of parts needed and you check it twice. A frame and armor (either ordering or 3D printing it) – check. Motors and wheels – check. A great weapon that will shred your friends’ bots – check. A receiver and ESCs (electronic speed controllers) – check. Wires, connectors, belts and switches – check. But it seems like something is missing. Hmmm… Yikes! No battery!

You have thoroughly researched all the other parts, but you totally forgot about a battery. How’s your little destruction machine supposed to come to life without any juice? Time to jump online for a little more digging.

LiPo Batteries

You find out LiPo batteries (Lithium polymer, sometimes also abbreviated as LiPoly) are the batteries most used for smaller bots due to weight and size. You go to your favorite supplier to order one, but the site has a bunch of them. Then you start noticing all the specifications: S… V… mAh… A… C… mm… Holy crap! How do you know which battery you need?

Voltage and Cells

You notice the battery above is listed as 2S 7.4V. You figure the V stands for voltage. But what is the 2S? With this LiPo, the 2 is the number of cells in the battery, S tells us the cells are wired in series, which means the voltage of each cell is added together to determine the total voltage of the battery. A single LiPo cell has a nominal voltage of 3.7V. A two cell (2S) LiPo has a total voltage of 7.4 volts, three cells (3S) at 11.1 volts, four cells (4S) would be 14.8 volts, and so on.

Capacity of LiPo Batteries

The capacity of a battery is typically specified in milliamp-hours (mAh), which indicates how much power it can produce. In the above case, the battery is rated with a capacity of 250mAh. But we don’t stop there. Next we need to multiply the capacity by the continuous C rate listed on the battery, which is the capacity multiplier. In the case of the battery above, we would multiply 250mAh by 35, which would give us 8,750mAh or 8.7 Amps. Will that be enough to power our bot? Maybe, but we need to do a couple more calculations just to make sure.

Time For More Math

To make this simple, let’s say you are building a antweight wedge with no weapon. You have two FingerTech “Silver Spark” 16mm gearmotors to use for the bot.

Checking the specifications for the motors, usually listed in the seller or manufacturer’s item description on their website, look for the stall current. This is the maximum current draw (in Amps) that the motor will pull when it is completely stalled. We find the the motor is rated at 1.6A each. So 1.6 + 1.6 (two motors) = 3.2 total amps for both motors. If our battery can deliver 8.7 Amps, it seems like that would be more than enough for our needs. But would it be enough for the duration of a three-minute match?

Now we divide capacity by current – 250mAh / 3.2A (or .25Ah / 3.2A for even dimensions), which is .078A per hour. Multiply that by 60 (seconds) and we find we can draw 3.2A for 4.7 minutes. Enough for our needs.

That would work for our antweight wedge. But if you want to add a weapon, you may need to find a battery with a little higher capacity. You just add the weapon’s motor or servo’s stall current to those of the motors. A 300mAh battery would probably work just fine, but do the math to make sure.

Size and Weight of LiPo Batteries

Size matters when it comes to the smaller competition classes (fairyweight, antweight, beetleweight). Real estate is at a premium with less area to store the battery. So don’t forget to factor in size and weight of the battery when planning a new build. TIP: you need an accurate set of scales to make sure your bot is in compliance with the weight class you plan on competing in. A good set of digital kitchen scales should work just fine.

Conclusion

Now you know how to determine what battery you need when planning a new combat robotics build. Battery safety and correct charging and discharging is also important when working with LiPos, but I’ll save that for a later blog.

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