Hi! Today I am going to make a Compass bot. I got this idea by thinking on how hard it is to draw the perfect circle without a mathematical box. Well I got your solution 😆. As you know that a circle is exactly 360 degrees, so this bot can draw a shape that is exactly 360 degrees and that shape is the circle. Now let's get started.

Supplies

Materials

Rigifoam sheet (thicker the better)
Gear motor
Battery
Wires
SPST Switch
Kebab stick
Rubber band

Tools

Scissor
Screw driver
Hot Glue Gun
Mathematical box (to draw a circle)

Step 1: The Wheel

Use the compass and draw a circle in the Rigifoam and cut it out. Then make sure that its sides are smooth (because its gonna be our wheel). Then make a hole in the middle of our wheel with a Screw driver.

Step 2: Attaching

Then fix the wheel into one of the gear motors sides as shown and paste it with Hot Glue. Then attach the battery snap and clean the wires of it until the copper shows up.

Step 3: Connecting the Wires

Then connect the SPST Switch, the Gear motor and the battery together and form the above connection using the extra wire.

Step 4: The Body :part 1

Then cut out three Rigifoam pieces as shown. 2 of them are 15cm in length and the other 6cm in length. The width should be equal to each other. Then place them as shown above.

Step 5: The Body :part 2

Then take one of the long Rigifoam pieces and the short one. Then take one side from each of them and cut out a slash ( / ) in each side as shown above. It should be cut until, when they are placed together you get 90 degrees in the middle as shown. Then take the left out piece of Rigifoam and cut out slashes as shown above.

Step 6: The Body :part 3

Then all of them should be placed together.

Step 7: Pasting!

Then use the Hot glue gun to paste them. Paste the Gear motor in a way that the wheel is facing outside.

Step 8: Pasting Continuation!

Then take your battery and switch, and paste them too! You can paste them in any position you like...

Step 9: Making the Hole

Then when all of them are pasted use the screw driver to make a hole at the corner of the bot. You must make a hole that is big enough to place a Kebab stick through it. Then place the Kebab stick.

Step 10: Placing the Pencil

First keep the rubber band on the table and keep the tip of the pencil inside the loop. Then raise the rubber band from behind as shown and then take it above the pencil and place it as shown in the third picture. Repeat the last instruction until the pencil is tightly placed and cannot be moved easily.

Step 11: Keeping a Handle (optional)

Cut a straw and place it on the Kebab stick then when you are using the bot you could use the straw as a handle!

Step 12: Beautifying It!

Take a piece of any designed cardboard you like and cut a strip of it and paste on one side of the Compass bot. You can also put a strip to the Kebab stick. You can also paste a piece of cardboard on the Battery too!

Step 13: Other Small Attributes

You could use the cardboard to make a stopper so that the straw won't go to the bottom. Plus you could write your name in a piece of paper and paste it!

Step 14: How It Works

First you should hold the handle (straw). Then on the switch and the wheel would rotate.
Let the wheel turn on the the table, in that way the whole bot will turn.
When the bot turns the pencil will draw on the the paper and in that way you would get a perfect circle! (plus you will need to practice this so that you could hold the Kebab stick in one place)

To understand the instructions better you could download the following video which gives all the instructions you need. 😃 Hope you understand the way it works! (plus I also don't have practice...😅😂)