Though mostly associated with country music, there's a pretty good chance that you've heard the sweet singing tones of a lap steel guitar in whatever modern genre floats your boat. OK, maybe not techno or electronica, but certainly blues, rock, jazz and folk music. Rather than gently stroke the six to ten high action strings of an electric lap steel with a glass or metal bar though, Dean Miller opted to recreate the sound using four servos controlled by a modified foot pedal array and an Arduino running some custom code. The result is pretty astounding.
Miller (aka gr4yhound) took around two months to develop and build the Tele Servo Bender in his spare time. He first tested his idea for a servo-activated detune using a simple setup of a spare neck bolted onto a piece of ply, the Arduino, an analog servo and a breadboard, before starting work on routing the cavities in a Telecaster-shaped body. He bought a cheap bridge and bored through the screws of the saddles to allow the A, D, G and B strings to pass through.
An aluminum mounting plate for the analog servos was cut using a homemade CNC, and the cavities containing the guitar pots and switches, and the one housing the servos, shielded to help reduce noise interference. The servos were lined up with the appropriate string, which runs over a 3D-printed pulling horn to control the speed and distance of the bend.
Miller stripped out the circuitry of a keyboard sustain pedal and installed a magnet and a continuous ratiometric hall effect sensor for smooth bend control. There's one pedal for each string. He says the easiest part of the build was the creation of the code for the microcontroller, which he's made available for anyone who wants to build their own Servo Bender.
As you can see and hear in the video below, the DIY project is so convincing that you can almost feel the jaws of lap steel players dropping as Miller runs through a few tasty licks.
Source: Dean Miller