Lego Sherlock Holmes figure focuses a light beam on a Lego criminal with a small magnifying glass.

LEGO Pneumatic Artillery

cannon for shooting round bricks.

Adventures with pneumatics continues with this artillery piece that shoots 1 x 1 Round Bricks. Compressed air flings the brick bullets out of a tube. The hard part of this design was finding a tube of inner diameter to accommodate the round bricks. My solution for the tube was found at with a 0.5” x 0.083” x 0.334” aluminum tube. In a random length somewhere between 10-12”, this tube cost $5.55 plus shipping. I cut the tube to about 6-inches length, then “painted” it with a blue Sharpie marker (the blue on aluminum looks purple). Shown in the video below is 50-psi blown into the tube, with several bricks loaded as bullets. If the round brick bullet has an open stud, I cap it off with 1 x 1 Round Plate (or tile, or anything round that doesn’t have a hole in it). A LEGO pneumatic tube is connected to the end of tube and sealed in place with sugru (; I love this stuff). Compressed air is provided by the design shown in my other blog post “LEGO Regulated Air Compressor.” The compressor pushes air into a tank, until a pneumatic switch triggers air to flow into the artillery tube. Pressure inside the tank is measured in this setup with a manometer, which can be seen in the video at an initial pressure of 50 psi. Oh, and don’t forget safety glasses.