Introduction: Motorized Marble Roller Coaster

About: Hi, I'm Sam and I like to make things - check out some of my projects below. I worked for this site from 2014 - 2023 and have nothing but love for the Instructables community. Keep making great stuff!

This is a roller coaster for marbles. It's made from lots of cardboard and hot glue, some stuff out of an old broken printer, and a few other odds and ends I had laying around.

I played around with cardboard, tape, glue and marbles a lot as a kid, making tracks and ramps and such just for fun.

I had been wanting to make one of these for years, just to see what I could come up with now that I'm a little older. The main thing I'd been wondering about was how I could get the marbles back to the top with some sort of mechanism made from simple, available items.

Step 1: Supplies

I gathered up quite a bit of craft cardboard for this project, along with a few old boxes from the trash.

I used lots hot glue, along with some wood glue and white glue in a few places.

Step 2: Base

The base is made out of MDF. It is 20 inches by 40 inches, and about 4 inches tall.

Step 3: Original Motor Assembly

(This was quite the hack job, but it worked.)

The electric motor is out of an old printer. The drive is made from a section of cardboard tube, along with MDF glued to the inside, and rubber bands placed on the outside to give traction to the conveyor belt.

The motor was hot glued directly to the base, and the geared end of the motor was pressed against a rubber band on the conveyor drive. The power comes from four double-A batteries in a holder from Radio Shack.

Step 4: Conveyor Belt

The conveyor belt is made from 72 inches of nylon webbing, with 3/4 nails placed through it every 3 inches. The nails are glued to small folded pieces of thin white cardboard, which keeps the nails standing up straight when they are pushing against a marble.

A cardboard guiding track was built around the conveyor belt. This V shaped track keeps the balls centered on the belt. A thin piece of wood was built into the track under the belt which keeps the belt from sagging.

I added little triangular pieces of cardboard to the front of each nail and "flag" which keep the marbles in place on the track while they are being pushed along.

Step 5: Track

I used strips of corrugated cardboard that were glued to form T beams as the main supports for the track. Each section of track is made from two corresponding pieces of single-ply cardboard that form a V-shape. Small strips of cardstock-like cardboard were used to glue the track strips together. Please examine the photos for detail.

I made up the layout of the track as I went along. It took a lot of trial and error to create all the various sections of track that curve, dip, rise, etc. The trick is to build and test with a marble as you go, and if it works, great--if not, take it apart and try something else.

If you're interested in making a marble coaster but are somewhat scared by the complexity of my project, take a look at these instructions for building simple marble tracks (shared by user Covo).

Step 6:

Step 7: Upgrades!

I dug around for more parts I had kept from the old printer and found a small rubber belt along with a bunch of gears. These were put to use to slow the lift down to a nice, roller coaster-appropriate pace.

I modified the cardboard drive cog to accept the new motor belt, and added a tower to house the motor, gears, and battery pack.

Because of the slower lift, I had to make some adjustments to the positioning of the upper portion of the track which receives the ball off of the lift. This slowed down the track somewhat, so I also had to switch to using steelies (heavier metal marbles).

Prior to painting, the tower looked a lot like a prison yard guard tower. That was unintentional.

Step 8: