Bike wheel powered Pea-Shooter

Prints (0)


You'll need a bag of dried chick peas (garbanzo beans) as ammo and some elastics to build this project and some 2" 3/16th bolts to put it together.  I also used two paperclips as pins to hold the axel pin and drivewheel pin from slipping out.   Really you could use any projectile about the size of a chickpea, but I chose chickpeas as they are bio-degradable and also tasty.

The basic function of the pea shooter is that the spinning of the front wheel powers the gun.  when you drop a chickpea down the ammo tube gravity pulls it to the flywheel where it is grabbed and flung forward.  The faster you are travelling the further the peashooter will shoot.

When you are done playing with the pea-shooter

I used my standard handle bar mount as the basis for this project:

I recommend you print all parts with at least 2 shells and 25% infill.  No supports are needed to print anything.

It's still work in progress, getting it to work correctly very much in finding the right tension balance between the elastics that pull the wheel that rides on the bike tire down and the tension of the belt that spins the flywheel up.  I also want to add a trigger button, right now to fire a pea you need to drop it down the loader tube and it fires right away.

Have Fun!


First attach the two center bar clamps on either side and as close to the center post as possible.  I used a 3/16 1" bolt and nut to secure the camps, you might want to go a little longer, say 1 1/4" though.  Loosely bold them in place but do not tighten them up yet.

Next place the clampbar over the handle bar clamps and center it  then tighten down the bar clamp bolts.  the clamp bar has many different attachment points all over it's surface to attach things to.

Clip the clips over the posts to secure the whole assembly in place. 

If you want to take the assembly off just remove the clips and pull off the clampbar while leave the handle bar clamps where they are.

Next attach the barrel to the clampbar with a 3/16" bolt.

Next attach the pivot_bar to the clampbar with two 3/16" bolts make sure the fins sticking out at the bottom of the pivot bar are facing towards the read of the bicycle.

Attach the fork to the pivot_bar with the fork_pin.  stick a paperclip through the hole at the end of the fork_pin to secure it in place. 

Attach the driver wheel to the fork with the driver Pin and use a paperclip through the whole at the end of the driver_pin to secure it in place. the driver wheel should be resting on the front tire.

Bolt the driver plate to the clampbar with 2 3/16th inch bolts.

Wrap elastics around the grove in the flywheel as in one of the pictures provided.

Attach the flywheel so that it sits in the groove in the barrel with the flywheel axel (I added some grease so that everything spun freely.  Put a paperclip in the whole at the end of the axel to hold it in place on the driverplate.

Tension the fork to the bike with elastics.  You may have to tie a few elastics to do this.  The harder you can press the driver wheel onto the bike tire the better.

cut a few skinny elastics in half and tie them together.  Run the elastics through the hole in the fork around the driver wheel and up around the knob at the end of the flywheel axel.  This should be as tight as you can get it without pulling the driver wheel off the front tire.

lift the front tire of the bike off the ground and give it a spin.  This should cause the flywheel to rotate smoothly. while it is spinning drop a dried chickpea down the hole at the top back end of the barrel.  It should fire out the front.

Design Files

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