This is a modified Mr. Potato Head toy with wheels and a motor allowing him to move on his own. The parts used here are from VEX.

Step 1:

Screw a shaft collar onto a 3" shaft and place inside the rear end of the long hole on the bottom towards the back of the toy, with the larger section of the shaft pointed down and the shaft collar located inside the toy. Hot glue the shaft to the inside of the hole to stabilize. Add another shaft collar, this time on the outside of the toy to prevent the shaft from moving vertically.

Step 2:

Place a VEX motor inverted on the inside of the toy, oriented so the part that rotates is located on the opposite end of the long hole as the shaft. The 2 screw holes should be just under the middle of the long hole. Using 2 0.5" small-diameter screws, screw the motor to the long hole

Step 3:

Place a 2" shaft in the motor and secure with a shaft collar on each side of the long hole. Do not stabilize with hot glue as this part needs to be able to rotate. Place a bevel gear flush with the bottom of the shaft, as shown.

Step 4:

Obtain a 3" shaft. Starting with a shaft collar 0.5" from the top, add these parts from top to bottom to create the wheels: pulley wheel (non-spinning), bevel gear (side with teeth facing down), small spacer, bearing block (center hole), large spacer small spacer, pulley wheel (non-spinning), then another shaft collar.

Step 5:

Viewing the parts from the previous step from top to bottom and using a 0.5", normal diameter screw and Keps nut, screw an end of a lock plate above the left hole of the bearing block

Step 6:

Screw a shaft collar 0.5" from the top of a 2" shaft. Place the long end through the bottom of the middle of the lock plate, then add (in order) a small spacer, a shaft collar, the left edge of another lock plate, a large spacer, and a shaft collar. There should be no spaces between any of these pieces.

Step 7:

Add this wheel piece to the immobile shaft on the bottom of Mr. Potato Head. Be sure to secure it with shaft collars as shown. The bevel gears should barely touch. To ensure stability, hot glue the top of the shaft made in the last step to one of the screws holding the motor.

Step 8:

Add a micro:bit battery pack or similar into the back of the toy, in addition to 2 20 g weights near the front of the toy (for stability), making sure that neither blocks any of the holes in the toy. Replace the cover on the back of the toy, keeping sure that both the end of the battery pack and motor are sticking out.