Use LEGO to Build Your Own Hand-Cranked Larson Scanner

You can now make your own manual crankable Larson scanner out of LEGO bricks and Crazy Circuits electronic components.

Cameron Coward
a year ago

If you’ve ever watched Knight Rider or Battlestar Galactica, then you’ve seen a Larson scanner. Those are the sweeping light effects seen on the front of the Pontiac Firebird inhabited by KITT and the faceplates of Cylons. The lighting effect is named after Glen A. Larson, who produced both of those television shows. When those shows were airing, the Larson scanner effect was chosen simply because it looked futuristic and implied “scanning” operations. Now, as Pete Prodoehl and Brown Dog Gadgets demonstrate, you can make your own hand-cranked Larson scanner using LEGO bricks and Crazy Circuits electronic components.

Crazy Circuits from Brown Dog Gadgets are LEGO-compatible electronic components. Those components can be snapped onto LEGO bricks and connected with conductive tape to prototype simple circuits. Normally, a Larson scanner would be built with something like a 555 timer to illuminate a series of LEDs in a sequence that sweeps back and forth. But, if you’re willing to turn a hand crank, you can achieve the same effect without the need for any IC chips at all. The Crazy Circuits components combined with a handful of LEGO bricks just make it easy to form the circuit.

To make this Larson scanner, you’ll just need the proper LEGO bricks and a Crazy Circuits kit. The specific kit you purchase doesn’t matter, so long as it has a switch, battery, and LED modules. The circuit is quite simple, and connects each LED to the battery via the switch. The only complex portion of the project is the hand-cranked cylinder. That cylinder has sections of conductive tape that complete the circuit for two LEDs at a time. Those tape strips are arranged in a pattern that causes the LEDs to illuminate consecutively. If you get bored of the standard Larson scanner sequence, you can even rearrange the tape strips to create new patterns!

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