Aim of the challenge

A truck has over-turned, spilling its cargo of drums containing toxic slime. One of the drums has split and contaminated some of the others. There are x clean drums (which are green) and y contaminated (red) drums. Your robot must deliver the clean drums to the clean zone (which is blue and on the left-hand side of the arena) and the contaminated drums to the contaminated zone (which is yellow and on the righthand side of the arena). Your robot can push the drums across the arena or pick them up and carry them.

Time is of the essence; the task must be completed as quickly as possible to avert an Ecological Disaster!

Watch the video of Doofus showing how it should be done.

Control method

Remote control or Autonomous.

Teams in the Schools, Beginner and Intermediate category may choose to use remote control. Advanced category teams must do the challenge autonomously.

Time limit

Robots will be allowed 5 minutes to correctly sort as many of the barrels as possible.

An additional 2 minutes at the start of the challenge can be used for calibration.


  • Robots will be placed in a starting box.
  • The challenge arena is shown as a diagram below (click to embiggen). Dimensions are in mm:
  • The arena has a perimeter wall which is 300mm tall. The dimensions in the diagram define the inside edge of the wall.
  • The arena floor and walls are painted matt black apart from the clean and contaminated zones. The wall behind those zones bears the appropriate colour for the zone for the entire height of the wall. Decorative decals will be applied to the arena, these are only grey scale in colour.
  • The barrels are curved and are 80mm high and 56mm in diameter. They weigh 46g and are 3D printed in PLA. They slide easily on the arena floor so long as they are pushed gently from a position low on the drum. Push them too hard and they may topple and start rolling around; this makes the game much more difficult! The number of barrels to be used is to be determined. An STL file of the barrel is available here, zipped up.
  • Multiple drums can be pushed/carried at once but you are not allowed to touch the drums by hand.
  • Circles with small coloured dots will marked on the arena floor showing the start locations of the drums which will be the same for all teams. The judge will place the drums on their marks when preparing the game.
  • Drums will be placed within a designated box which leaves a 300mm space between the walls and drums; this is to allow space for robots to manoeuvre between the drum and wall if required.
  • We will attempt to provide even, diffuse, white lighting across the entire arena to assist with autonomous vision systems. However, teams should try to build vision systems which are robust under non-uniform lighting conditions.

Vision System Calibration

A small area will be created next to the main arena which will contain boards bearing the colours of the clean and contaminated zones. Drums in the appropriate colours will also be provided. This will enable teams to calibrate the colours within their control systems for autonomous machines outside of their designated competition time. However, teams may also calibrate their machines in the live arena for two minutes before their 5-minute run.

Detail of the paints used for the arena and drums will be published prior to the games. Hue values will also be provided to assist with vision system calibration.


Points will be awarded for each barrel correctly sorted. The actual number of points-per-barrel will be determined later, but expect the number of points to be at least doubled under autonomous conditions. Expect, also, that bonus points will be awarded for each x barrels, so for instance a bonus would be applied after every 3rd barrel is sorted.

There will be no penalties applied for rescuing the robot.

For ranking purposes (i.e. for the medal), robots will be timed. Tie-breaks will be settled based on the highest number of barrels sorted in the shortest time.

At the end of the allotted time, the Judge will count the number of drums successfully delivered to the appropriate zone. A drum will be deemed delivered if any part of it is touching the appropriate coloured floor patch.

If a team delivers all drums in less than the allotted time, then the overall time taken will be noted.

If a drum is delivered but is then inadvertently pushed out of the zone, then it will no longer be “delivered” unless it is returned to the zone. The robot delivering the most drums within a category will win that category.

If multiple teams deliver all drums, then the quickest team will win first place.

Ask Questions and Discuss

You can discuss this challenge and ask questions on the discussion forum or via Discord chat.