[Editor's note: This interactive feature previews foam_FORM's performance on Hear Nebraska FM, starting tonight at 6. Tune in at 89.3 FM, or stream at kzum.org.]

Conner Goertzen wanted to show the audience what he was doing onstage.

He wanted to show that he isn't checking his email while performing as foam_FORM. No, Goertzen is triggering notes and samples with buttons and manipulating the sound with knobs.

So how did he go about showing the performance? He built his own instruments, wearable MIDI controllers that he slings over his shoulder like a guitar. He named them the Mobitar and the Trigguitar, instruments that tell a computer what to play through the buttons he pushes and the knobs he turns.

When building the Mobitar, his first effort, he found his most essential parts on Freecycle. The online community of people who exchange things for free provided him with the Dell computers from which he'd harvest the motherboards. After connecting arcade game buttons, knobs and the USB outlet that would connect the instrument to a computer, Goertzen finished the Mobitar in June 2011.

Since then, he's been mashing buttons in plain sight at shows in Nebraska. His electronic music sometimes juxtaposes hip-hop drum beats with bits and pieces of polka. Other times, it's a collection of bitcrushed blips over bass and snare, like Super Mario: San Andreas.

Here, at Hear Nebraska's Take Cover concert on Jan. 19 at The Zoo Bar, Goertzen stirred up a mix of Nebraska bands Prince of Apple Island and Sputnik Kaputnik:

Tonight, Goertzen will perform on Hear Nebraska FM, which starts at 6 p.m. on 89.3 KZUM. Stream the show online at kzum.org.

To preview, play an interactive version of the Mobitar below by starting the backing track and clicking the buttons to trigger samples. Hear the full song as composed for foam_FORM's album Ice Cold Cola Polka // Moonrock Elevator Tour further below:

CLICK TO START THE BACKING TRACK, THEN CLICK BUTTONS TO TRIGGER SAMPLES:

FULL SONG:

Michael Todd is Hear Nebraska's managing editor. The closest he came to creating his own instrument was when he spray painted his dad's first guitar, without his dad's permission. Reach Michael at michaeltodd@hearnebraska.org.