Surf the interwebs and get your heart pumping. Position your laptop on your exercise bike. You can purchase expensive plastic stands, thermoform and lasercut your own plastic model, use metal bar stock to build one, use pvc pipes to make one, or cobble scraps of wood but what if you can make one with just cardboard and glue?

This was inspired by Eric Wilhelm's treadmill desk. Not being Infantry, we don't walk using a desk, we ride, and thus...

This instructable is for the really cheap and frugal or maybe you just don't have cool power tools. Whatever, recycle some box cardboard into something useful.

WARNING: No long term studies have been done on using a laptop on an exercise bike but benefits may outweigh the risks. Consequences such as new forms of carpal tunnel syndrome or saddle sores and leg cramps from overuse may occur. As always, consult your physician before you embark on any intense exercise regimen. Your mileage may vary.

Step 1: Heavy Lifting...

Take a walk to the recycling bin to pick out a few large pieces of cardboard. If you only have smaller corrugated boxes to salvage from, that is okay to piece together smaller pieces of cardboard.

You will need:

Cardboard - stiff corrugated cardboard, IKEA boxes will do but because they are minimalist, you will need to layer them about twice as much.

Regular school glue

Scissors or utility knife to cut the cardboard.

Pencil or marker to draw guidelines.

A straightedge if you cannot cut a straight line.

Corrugated box cardboard is actually quite strong. We can make it even stronger by the way we use it. If you laminate or glue together several layers and turning the direction that the grain or corrugation runs for each layer, you will make something that acts and feels like it was made of wood. You can see my Giant Fn Computer Key Stool for other hints on using cardboard as a building material.

The paper facing from scrap pieces of cardboard is used to paper mache the exposed corrugations for a finished look.

Step 2: Figure It Out...

This cardboard exercise bike laptop stand is basically just a cantilevered shelf that is supported at the bottom by the small book shelf lip on the bike console. It is held in place by the weight of the laptop pressing on the upright handlebars.

Since this laptop stand is specific for this exercise bike, you may need to alter your design slightly.

This is an upright riding exercise bike as opposed to a recumbent - sit down, lean back model. Most control consoles have a little lip that is used as a book rest.

You usually have a set of handlebars that are bent upwards in front of the control console.

With this in place, we can custom design a laptop shelf by using the idea of a cantilevered shelf that sticks out, held up by the console and held from tipping forward by the handlebars.

Step 3: Crossbar Support

No need to really measure. Mock it up and size it right on the exercise bike.

Cut a strip of cardboard about 5 inches high. Make the length a couple of inches wider than the width of the handlebars to go beyond each side of the handlebar.

I cut it so that I could still see the display of the exercise bike when in use. I don't play with the buttons much so I could cover them but would need to slide the shelf up if I wanted to change the settings on the exercise bike if it was not on autopilot program.

Slide it in between the console and handlebars. It should rest on the book shelf of the exercise bike console.

If the geometry of your exercise bike does not allow this, you might need to figure out how to have it hang or suspending from something else, and possibly use tie-wraps or clamps to keep it in place.

Laminate about 4 layers of cardboard to your crossbar piece. Since the fate of your laptop rests in this bar, use as many layers as you can to fit the gap between your console and handlebars.

When dry, put it back in place for a second fitting.

Mark the end stops by seeing where the handlebars line up with the cardboard. They may angle inwards so trace a line to the cardboard.

Center your laptop in the middle of the crosspiece.

Mark the width of the laptop. You will build the shelf around that dimension to create a shelf.

At each end, layer several pieces of cardboard to create stop blocks at the ends. This will help keep the laptop shelf from shifting side to side. Test to make sure you can remove the crosspiece without binding against anything.

Step 4: Build Shelf

I had a tray-like box that actually fit the dimensions of my laptop. You can cut a large piece of cardboard and construct a similar tray to fit your laptop.

If you do not have a piece of cardboard large enough, just make a part that will be glued to the crosspiece support. You can extend it later by splicing more cardboard. Just use a piece of cardboard to bridge the joint. Since we are laminating layers and paper mache'ing the final product, don't worry about any seams that appear.

Glue the a flap on the end to the crosspiece. It should be positioned in the center.

From the side, look to see where the entire shelf will be level. My handlebars and console are sloped toward the front so we have to make the shelf in a level position when it is used.

With one of the tabs on the side pieces, bend and crease it so that the rest of the shelf is level when it is glued in place.

Bend and crease the other side tab and glue in place.

Step 5: Reinforcements

You can fold pieces into an L-shape angle iron and build up the sides of your shelf.

Glue the sides to the crosspiece and layer on more cardboard.

Use thinner width pieces as strapping to go over across the top the back corners. Lay those pieces diagonally and have it overhang the inside corner so you end up with a wing like structure or "web". This helps resist the pulling of the shelf off the crosspiece.

The excess length in the front of the shelf was just folded over and glued. It was fitted to the dimensions of the laptop. It is about 2 inches high but could have been about 1 inch. The sides could taper down to the front. As you can see, you can also taper the number of layers with less in the front portion.

Step 6: Bottom Detail

Since the book shelf lip of the exercise bike console sticks up an an angle, I wanted to customize the fit of our cardboard shelf over it.

From the bottom, trace out where you need to make a pocket to fit the exercise bike shelf protrusion. Layer cardboard around it. This also helps to keep our cardboard shelf in position.

Similarly like the top, add the diagonal strapping webs across the shelf corners on the bottom.

Layer up the bottom of the shelf to give it more strength.

With the cardboard shelf mounted on the bike, give it a little test to see where you may need to add more cardboard reinforcements. If you can squeeze another layer of cardboard behind the handlebar, it would help support the weight as the shelf is pulled. It will still flex a little without its layer of paper mache to tie everything together.

Paper mache every exposed joint and corrugation. I just peeled the paper facing from leftover cardboard to use as the material. I used straight unthinned glue to layer on the pieces.

Wait overnight for everything to dry.

Step 7: Let It Breathe...

I guess I could have just drilled a couple of holes to help in ventilating the bottom of the laptop as it sits in the shelf tray. I was using this Macbook so I had to make this a matching accessory.

Draw the logo or use a printed logo to trace from. I put the image backwards since I was working from the back to see where the thickest reinforcement plates were.

Use a utility knife to start slicing away and pick out the scrapple. When the logo is cut out, paper mache the raw edges.

Step 8: Burn a Few Calories...

So take it for a test run...ride.

I left my cardboard exercise bike laptop stand in its natural rustic brown finish. You can prime and paint or maybe put a clearcoat on. Maybe even decoupage it further.

You can substitute a portable DVD player or coffee table book for you laptop.

The shelf is strong enough for reasonable typing and flaming. I have not really put my body weight on it yet.

May not be suitable for spinning classes but it is well out of the way of moving knees. You cannot really ride standing up but the normal sitting position and viewing is quite comfortable.

Just do it.