Hate Your Feet? Check Out This LEGO Launcher
Adam Beedle figured that few things are more painful than stepping on LEGO, so he built a catapult to launch LEGO bricks at a person’s feet.
There is a trend in the maker community (largely due to the influence of the infamous Michael Reeves) of building painful contraptions for our amusement. Because most people aren’t complete monsters, they tend to direct that pain towards themselves. Adam Beedle is a budding YouTube star who is taking some lessons from Reeves’s playbook. Beedle figured that few things in this world are more painful than stepping on LEGO, so he built a catapult to launch LEGO bricks underneath a person’s feet. And that person is, of course, Beedle himself.
This isn’t Beedle’s first foray into self-targeting automated masochism. Several months ago, he built an AI-controlled Nerf blaster and programmed it to shoot his own face. But Nerf dart shots are kitten kisses when compared to the agony of stepping on a LEGO brick. Spitting in Isaac Asimov’s face, Beedle gave his robotic creation the sole directive of forcing its target to tread upon sharp Danish plastic. As soon as the robot detects a person (who is always Beedle, in practice), it locates their feet and starts firing brick after brick at them. The target is guaranteed to either step on a brick or, if they stand still, at least take a sharp corner to a toe.
The robotic turret uses a webcam to look for hapless targets. The webcam connects to a computer running some sort of computer vision software (probably OpenCV). The software seems to recognize Beedle’s red socks—not feet in general. That makes sense, as detecting and masking a specific color in a video feed is much easier than performing true object (or body part) recognition. After the detecting the red socks, the software tells the turret to turn towards them until they are in the center of the video frame. Then it starts firing.
Beedle 3D-printed the turret and its clever automatic firing mechanism. An Arduino Uno board controls two servo motors. The first rotates the turret so it can aim in the horizontal plane. The second drives the firing mechanism. That mechanism uses rubber bands to propel the bricks that drop down from a magazine-style hopper. The servo motor turns a rack and pinion gear set that pulls back the rubber bands and then releases them. The result, as you can see in the video, is focused podiatric torture.