Mesmerizing Self-Stacking Lego Domino Machine Can Hit Two Million Topples Per Day

A few months ago, Grant Davis designed and built a Lego machine capable of automatically stacking and toppling 120,000 dominoes in 24 hours. It was potentially a record-setting contraption, but Jason Allemann of JK Brickworks could absolutely shatter that with their latest Lego build.

Davis’ machine featured just 10 dominoes, which would fall in sequence before motorized mechanisms whirred to life and re-stacked all of them in a reverse order. It took about seven seconds for the cycle to complete, which seemed fast at the time.

Allemann, an incredibly talented builder who’s actually had several creations turned into real sets by Lego, took an entirely different approach. Instead of just 10 Lego dominoes falling in a straight line, Allemann’s machine has 64 falling in a perpetual ring, and instead of them being free-standing (with magnets in the base to ensure they’re realigned properly when stacked), those 64 Lego dominoes operate on hinges that help keep them in place at all times.

The re-stacking process is elegantly handled with a small train running around a track on the inside of the domino ring, which triggers a ramp that activates levers to raise each one back up as the train passes. So while on one side of the ring dominoes are falling, on the other side they’re being simultaneously re-stacked. To ensure the train doesn’t outpace the work of gravity, a Lego Mindstorms EV3 unit and a sensor help control its speed so that it always matches the speed of the falling dominoes on the other side. It is both pointlessly complex and fascinatingly clever.

The sensor also allows the Mindstorms EV3 unit to keep track of how fast the dominoes are falling. And with an average rate of about 1,500 dominoes toppling every minute, if the machine were left running without any unforeseen complications or breakdowns (it is assembled from a children’s building toy, after all) for 24 hours, it could potentially result in over two million dominoes falling. Allemann plans to start with a one-hour test of the machine to see how durable and reliable it really is, but what’s undeniable while watching the machine run in its current state is that if I had one of these on my desk, I’m not sure I’d every be able to do anything other than hypnotically stare at it.