Robot Build Guides & rules

Useful BBB Event tools: Judges Sliders, Arena Timers, Tip Speed Calculator, Code of Conduct.

Here we've put the UK rules and guides we've made in various forms to help you get building your own combat robot. Use the tabs to switch between the different weightclasses.

Antweight Robots

150g in weight and size must fit within a 4" cube. Recommended Parts list

Slides: Intro to Antweight Robots

Video of the talk. By Joe aimed at Bristol Uni students.

Video: How Much Do Fighting Robots Cost?

by Ryan from Spinnerproof. Parts and tools to get started building ants (and beetles!).

BBB Ant Kit Guide

An antweight starter kit you can buy here. View full guide here.

UK Antweight Rules


Bristol Ants (BAnts) Antweight Modified Ruleset

BAnts are a modified 2v2 Antweight ruleset, legal at BBB pub-based events. The class is designed to encourage newcomers into destructive fights while also allowing more flamboyant designs for seasoned builders. Rules:

175g max weight. 250g for non rollers. Whole robot must start within a 125x125mm square on the arena floor. No overhangs. Cluster bots wider than 125mm must start stacked.

Plastic chassis & weapons materials only. No metals except for fixings, electronics, motors. Check the list below if in doubt:

Yes: PLA, ABS, Nylon, Polycarbonate, HDPE, rubber etc.

No: Metals, NylonX, Onyx, Carbon-fiber, kevlar, fiberglass etc.

No acetate or similar flexible thin material acting to eradicate ground clearance or slide under opponents.

All entries are at BBBs discretion and these rules are subject to change. Please consult us in advance if you have queries about material choice or size limit.

Remember, by utilising the size or weight bonus you sacrifice making your bot legal in normal ant competitions, including our regular 1v1 tournament.

Typical BBB pub event format will consist of the 2v2 BAnts tournament, a Bodgebots XL Tournament, and finally a 1v1 full combat UK Ant tournament.

Useful links:

- Antweight forum

- Antweight Combat Robots Facebook Group

- Bristol Bot Builders Facebook Group

- UK Robot Combat Events Calendar

Bodgebots XL

500g in weight, no size limit. Recommended Parts list

What's a bodgebot?

A bodgebot is an combat robot, however it's thoroughly 'bodged' - often made last minute from bits of scrap, tape and a lot of glue and costs maximum £40. It's an opportunity to try out fun concepts and be daft with your builds. Bodgebot rules below!

Some example bodgebots from recent events!

Bodgebots XL?

We're doing bigger bodgebots - 500g of bodge! We want to give people a taste of the larger 1.5kg beetleweight class, but with a comedic barn fighting style - the arena is be a low walled rectangle with lots of dumb hazards, gaps and no polycarb walls (see tip speed rules)

Bodgebots XL arena - crappy hazards, toilet pit and housebot!

The Spirit of Bodgebots

Bodgebots are about building something fun, to produce enjoyable fights for builders and spectators, using unexpected materials and designs. As such, we ask everyone to adhere to the spirit of Bodgebots, so that everyone attending can have the best time possible.

Bodgebots are a class taking inspiration from a similar class in the US. These 'Spirit of Bodgebots' rules are adapted from their own.

- The spirit of the class is low-to-no-cost robots made as much of materials on-hand and recycled/repurposed as possible, built mere days or hours before the event.

- The object of the competition is not to win. If you win the competition, your robot was inherently not bodge, and is therefore subject to disqualification.

How do I make a robot?

A basic robot has these electronics:

- Battery - to provide power for your bot

- Speed controller - drives the motors

- Motor - to drive a wheel or weapon

- Receiver - to get a signal from your controller

Bodgebots Recommended Parts
Drive Motors

The motors that you connect to wheels or legs to make the robot move

Drive Speed Controllers

These make your drive motors move when you connect them to a reciever

Weapon Motors

The motor that moves your weapon - such as a flipper, lifter, grabber, axe etc.


Powers your bot

Transmitters & Recievers

The controller to drive your robot and the receiver to receive that wireless signal

Bodgebots XL Rules

Max weight: visually 500grams (750g for walker/shuffle bot)

No size limit / cube rule

Max Tip Speed: 14mph (no more than 6m/sec) Tip speed calculator here.

Max cost: £40

Parts that DO count to the cost:

- All major electronics (motors, receivers, speed controllers etc)

- Purchased materials (wheels, polycarb, metal etc)

Parts that DON'T count to the cost:

- Decorative parts (googly eyes, paint etc)

- 3D printed small parts (not the entire chassis!)

- Recycled materials

- Tools, Wire and shrink wrap etc

- Transmitter

General rules:

- There must be an easily accessible way to turn your robot off with one hand. (link / switch / visible battery connector)

- Liquids may not be used in combat situations.

- Your robot must be safe for combat without polycarb screens - BBB have the right to reject your robot from competing if deemed unsafe

- If winner of fight unclear, judging voted by mob rule (audience cheering)

Bodgebots XL example build

Taking out the trash - a dustpan grabber bodgebot

- The dustpan was £3 from wilko.

- the motors cost £8

- the wheels cost £4

- the dual speed controller cost £10

- the receiver was around £9

- the lipo was 76p (came in pack of 5)

- the servo was £5

Total spend around £36.

Beetleweight Robots

1.5kg in weight, no size limit. Recommended Parts list

Slides: Building a UK Beetleweight Robot

BBB official guide by Craig & Joe

Sir Lance-a-Frog - Beetleweight Lifter Teardown

Made by Team DSC. Thanks Nick! Click to enlarge.

Video: Building a Beetleweight Crab Robot

Joe's first Beetle in 2018, to give you a taste of newbie building.

Video: BBB: The History of Snappy

Craig's beetle build from 2014-2020, showing what's involved in beetles.

FRA Build Rules

(from the Fighting Robots Association website)

UK 2019/2020 Beetleweight Rule Updates

Weight limit is 1500g with no weight tolerance - provided event organiser has calibrated scales

250mph theoretical tip speed limit on all spinning weapons. Tip speed calculator here.

Cluster bots now require 67% elimination by weight. Judges/Refs must know weights of each segment pre-fight.

July 2022: Gyro walkers and shuffler robots receive a 33% weight bonus. This will result in them being allowed to weigh up to 2000g. Walkers (each leg with 2 degrees of freedom) can weigh 3000g.

Cluster bots with both a shuffling and wheeled robots: the weight bonus to the shuffler will be applied to the remaining left over weight after deducting the wheeled robots combined weight.

Spring Loaded weapons can be locked in either an open or closed position.

Useful links:

- FRA Events Tech Check Sheet

- FRA Competition Regulations

- FRA Beetle forum

- Beetleweight Robot Combat Facebook Group

- Combat Robotics Facebook Group

- Bristol Bot Builders Facebook Group

- UK Robot Combat Events Calendar

Featherweight Robots

13.6kg in weight, no size limit. Recommended Parts list

A guide to support teachers looking to run a combat robotics club - (feather focussed) by Dan Grant

Video: Building a Featherweight robot in a week

Joe's first Feather in 2018, to give you a taste of newbie building.

BBB Feather Drive Kit Guide

An feather starter kit you can buy here. View full guide here.

Slides: Adding a weapon to your BEVs Featherweight

How to use linacs, drills and scooties as weapons & some example bots to give you some ideas!

FRA Build Rules

(from the Fighting Robots Association website)

Bevs Ruleset (Bristol Fevs (Feathers))

BEVs are basically non spinner featherweights, inspired by American sportsman rules. The spirit of BEVs is a good time with non destructive featherweights. Creative flare, theming and showmanship encouraged!

2022 UPDATE: Active weapon required (eg - lifter, hammer, grabber, flipper). Torque reaction (overhead) thwackbots are permitted. Sit & spin / flail bots are not considered active weapons.

FRA featherweight rules apply: 13.6kg, link, fuse, sharp edge protection, cradle, locking bar, failsafing.

No metal forks & no sharp wedges/axes - to protect our wooden floor. We recommend plastic hammers & forks. No unsticks if you're stuck on an arena wall!

Max Tip Speed: 14mph or 6m/s for non-drive continuous rotation elements. Tip speed calculator here.

Pneumatic Pressure Limit: 10Bar (145psi)

Shuffler robots receive a 25% weight bonus. Aka max weight 17kg.

Open Arena: Your robot must be safe for combat in an open top arena. Any weapon systems that may be capable of tearing off pieces of the opponent (flippers, axes, etc…) must be cleared with BBB prior to competing.

All entries are at BBBs discretion and these rules are subject to change. We may tape up wedges or even ask you to remove forks if they are likely to damage the arena.

Useful links:

- FRA Events Tech Check Sheet

- FRA Competition Regulations

- FRA Feather forum

- Combat Robotics Facebook Group

- Bristol Bot Builders Facebook Group

- UK Robot Combat Events Calendar

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