Steve Schuler wanted to build an oscilloscope. He used LEGO, an Erector set, a LittleBits motor and a Raspberry Pi which generates the PWM necessary to drive the motor. The motor is hooked up to a spinning mirror that sweeps the laser across some graph paper, creating a straight laser line. The motor control is programmed on the Pi using ScratchGPIO. You can read more about it on Steve’s blog post or watch the video below.