theremin mod after theremin mod, but those seeking that distinct sci-fi sound without the physical labor or hefty price tag haven't had much of an outlet until now. Meet Beep-It, a $35 analog optical theremin that sports a simple on / off switch, volume control, one quarter-inch jack, and light sensitive resistor to make you the master of that otherworldly sound. According to its creator, Michael Una, the little sonic music maker started off as yet another mod -- a "single-oscillator square wave theremin" in a petri dish -- back in 2008, and underwent a number of incarnations before getting the wood grain treatment you see here. Beep-It is now available at select retailers or direct from the company's website -- then again, we suppose you could hire Bobby McFerrin to do the same thing. Trippy demo after the jump.