You've probably heard of LEMUR in relation to its mounting of Ballet Mecanique - George Antheil’s 1924 composition for, among other things, 16 player pianos - at Washington DC’s National Gallery of Art last spring. To refresh your memory, LEMUR stands for "League of Electronic Musical Urban Robots." Taken straight from their website, "LEMUR's philosophy is to build robots that are new types of musical instruments, as opposed to animatronic robots that play existing instruments."

A perusal of the LEMUR turns up a wealth of pretty videos, and one of the simpler ones appealed to me. It's a collection of "ModBots" whizzing and banging in a church sanctuary, a lovely place both acoustically and as an aesthetic environment for these little guys. Check it out in this video, and if you want more, here's an excerpt from a LEMUR paper, further describing the ModBots:

ModBots are miniature, modular instruments designed to affix to virtually any structure, thereby allow the composer musical control of anything from a battery of specially designed instruments to structural surfaces within preexisting architectural space. With an emphasis on simplicity, each ModBot design usually consists of only one electromechanical actuator (a rotary motor or linear solenoid) which responds to varying degrees of supply voltage regulated by a microcontroller. This single-actuator design philosophy demands that all mechanical movement within the instrument be subordinated to the physical capabilities of the lone motor or solenoid employed. While this may sound like a limitation, such use of mechanical design (as opposed to more “intelligent” electronic design) brings a reliability, mechanical consistency and modularity that would otherwise not be possible.

Each device can be fitted with a variety of mounting harnesses and is connected to the brain (box containing the microcontroller, control circuitry and power supply) via a single run of cable. Thus, the microcontroller administers the appropriate voltage to hit, shake, scrape, bow, spin or pluck sound from any sonorous object with the precision one would expect from digital control. HammerBots (the ModBot beater device) for example, can be fitted with any striking device to play loud or soft with a speed and consistency unavailable to human percussionists.

SpinnerBots apply friction to a circumference in much the same way rubbing one’s finger on the rim of a wine glass causes the glass to ‘sing’. Though usually fitted with round telephone bells, SpinnerBots can also make metal tubing “sing” with a rotary bowing action. RecoBots use a high-performance servo to scrape back an forth along an attached surface with precise control over the position and speed of the scraper. Most commonly, RecoBots scrape the sides of springs lightly stretched over a resonator. SistrumBots use a solenoids to pull a set of jingles back and forth and allow precise control of tambourine-like shaking sounds. VibroBots consist of eccentrically loaded motors which, when activated, shake at frequencies too fast to be rhythmic and too slow to be a pitch.

A general bowing device, the BowBot is a bow-wheel lowered to a surface by means of a centrifugal clutch which engages when the motor is driven. BowBots can be used to bow strings, sheets of metal or nearly anything that responds to constant friction. PluckBots agitate a surface in the same way that a bassist plays pizzicato. PluckBots are used to play steel tongues, wires and strings. Because of their small size, versatile mounting capability and minimal cabling required for installation, ModBots can be configured in limitless arrangements. In addition to use in custom instrument designs, ModBots have brought MIDI capability to such places as museum stairwells, steel hulled ships and the sculptural work of other artists. designers, they provide compelling new means of musical expression.