A portable small robot arena idea for the classroom, science fairs, small robot challenges etc. and sized to suit the L0Cost robots.

It's made to fit common portable table sizes and a few pictures of usage ideas are included, one doing the regular line follower demo, another an obstacle course and yet another playing sokoban.

The photographs were mostly taken inside the living room of my house, not very big, where it was being used for play. Two of the photographs were taken from a robot workshop. The first, with coloured bricks marking out the course, was before, the complicated one is an after picture of what the attendees experimented with!!! New piece of paper and we did it all again.

The size is 128cm by 67cm, or 4ft by 2ft, but that's just for my circumstances, there's no reason it can't be larger though it could get a lot more difficult to transport, and any smaller might make any games or challenges a bit limited. The size is really set by the optimum size for the acrylic sheet used. If acrylic sheet isn't used, then any size goes :)

Supplies

2 x 2.4m or 8ft partition studs (I found this was the best price per volume of wood locally)

3mm or 4mm plywood sheet to suit, I had some spare which cut to 128cm by 67cm but just needs to be sufficiently bigger than the acrylic sheet that it can be screwed to the frame easily.

acrylic sheet 60cm x 120cm (I used a standard size that was sold off cheaply due to edge damage)

screws

black electrical tape

lining wall paper

masking tape

Additional:

40mm square timber, I used offcuts. Actual dimensions don't have to be exact.

100mm fence post, again I used offcuts. Actual dimensions don't have to be exact.

Step 1: Basic Construction

All the dimensions were made with the size of the acrylic sheet in mind. The long lengths of stud timber are cut down to 2 x 128cm and 2 x 67cm sections, with 45 degree cuts to give a neat finish.

The four lengths are then joined with long screws through the ends to form the rectangle. The inside measurements of the frame are 60cm x 120cm.

The plywood is cut to fit the outside dimensions of the newly made rectangle, in this case 128 x 67cm and then screwed to the frame loosely

The sheet of acrylic is fitted into the frame so that it just slides under the frame edges, and the the screws on the plywood are tightened up to fix it in place. I left the white plastic protection on the acrylic in place underneath to give a good reflective background, but the plywood and stud timber could be painted.

The 40mm square timber is cut up into lengths of 40mm and 100mm, and any sharp edges are sanded down. These are used to build the obstacle course.

The 100mm fence post is sawn up into 6-7 lengths of 2.5cm. These are used as crates in the sokoban game.

Step 2: Line Follower Course

A length of lining wall paper is cut to length and using masking tape is fixed to the acrylic sheet.

Black electrical tape is then used to mark out a course on the paper.

Its a fun game to play making a basic course and then extending it to add loops and branches that the line follower may or may not follow. The one shown has been extended several times.

When tired of a course, or it's just got too damaged, the lining paper is unstuck and a new piece fitted. The masking tape comes off the acrylic sheet easily.

Step 3: Obstacle Course

The obstacle course is a great challenge for both remote controlled and autonomous robots.

The course shown in the pictures has been made from offcuts of 40mm square timber, sanded to remove sharp edges. and made as two lengths, 40mm cubes and 100mm rectangles.

The objective of this course is for the robot to navigate the course from facing the arena wall inside the box in the middle at one end, through the blocks and across the black line at the end.

If its just the challenge then scoring doesn't matter, but timing from crossing the start line to crossing the end line with time penalties for knocking a block down would be an idea, the robot with the lowest time 'winning'.

If it is a competition, mark the position and orientation of all the obstacles so that they can be replaced the same way before each run.

Step 4: Sokoban Course

The Sokoban game of the warehouse operative moving crates around is a fun robot demonstration, though large solutions are beyond small robot designs, small solutions can be used as competitions between robot and human operators. For more information see Wikipedia. If using a L0Cost robot then a solution could be coded in a file on the SDcard to be executed either on power on or from the webpage.

The pictures show a course laid out for a basic game, the 'crates' are offcuts of fencing posts and the robot must either be driven or solve the puzzle by pushing the 'crates' into their final positions over the target crosses.

This is a great game for simple robots which can only push but do need to be able to either turn 360 degrees on the spot or drive backwards. Moving the robot or 'crates' outside the black line isn't allowed.

The game is played by the robot pushing each crate to the next square. It can't push more than one crate at at time. Crates and robots cannot cross the black lines and crates must not be left across lines between squares. The game ends when all the target crosses are covered by crates

The challenge is both to actually solve the problem, and to do it quickly.

One of the advantages of using the acrylic sheet is that a puzzle can be designed on the paper, which can then be placed under the acrylic sheet making it easier to slide the blocks.

If robots moving outside the black line is a problem, then the wooden blocks used in the obstacle course can be placed around the outside of the black lines with penalties for touching them with robot of crates. Taping the wooden blocks together might also form a better barrier.