Step-by-step activities, like recipes: the materials, tools and skills each needs, the instructions, variations to try, and related resources: alt.ctrl activities, listed below by the products they build on, by spatial arrangement, and by design strategy. All are licensed CC BY-NC-SA 4.0.
For the alt.ctrl classes.
Play a ukulele with the chord shapes and melodic figures you know from the guitar's four highest strings: they sound a fourth higher, in a new key.
Build one battery-powered RP2040 base that takes Wii, USB, touch and analog controls apart and puts them back together as new instruments, with sound, a servo, LEDs and a small display.
Build a controller of stiff bamboo strips, placed for the thumbs, that press on piezoresistive fabric, so that each tine measures how far it is plucked, pressed or bent.
Tape strip, force and fabric sensors onto an electric guitar to find which parts of it can be reached while playing the strings, then glue down the ones that work.
Pull strings instead of pressing keys: a row of long-lever microswitches, each worked by its own string.
Many buttons close their contacts with conductive rubber, which is piezoresistive: read them as analog inputs and they report how hard they are pressed.
A keyboard and mouse adapter lets a console take a computer keyboard and mouse in place of its game controller.
Put a microcontroller with a USB host port between a game controller and the computer, pass everything through, then remap.
Drape conductive stretch fabric over an upturned bowl ringed with resistive and piezoresistive strips, and sense where the hands press, how hard, and how they strike and sweep.
Rebuild the Stylophone in conductive paper: a keyboard you play with your fingers, a paper pressure sensor for vibrato, one microcontroller, and a pizza box as the sounding board.
A wig with three strands, each sounding one note; braided together, they sound a chord. Made by Tess Buckley with Adrian Freed at the Stochastic Labs residency.
Two crocheted e-textile headpieces, one tuned to a minor key and one to major, that sound more as their wearers touch: a circuit closed through contact. Made by Tess Buckley with Adrian Freed at the Stochastic Labs residency.
Get a Gametrak's six tether readings and its footswitch into Max/MSP or Pd, and pass them on as OSC.
Make a Gametrak-style three-axis tether sensor from a string potentiometer and a joystick.
Play a theremin with Gametrak tethers: one hand's position sets the pitch, the other's pull the volume.
Hang a ball from a ceiling-mounted Gametrak: its weight balances the tether's pull, and its swing plays the sound.
Move sounds around a room with a Gametrak's tether and a sound spatialization system, and strike a virtual gong.
Tie a light cube between a floor and a ceiling Gametrak to sense its position and orientation, and play with how it twists.
Choose a Gametrak's range of motion with its tether length, and use it to follow conducting gestures.
Pin a Gametrak tether along an angled pole to make a plucked, stopped string, like a tea-chest or washtub bass.
Add conductive thread to a tether and a conductive fingerboard, and time touches with the footswitch input: a simulated trautonium.
Take Gametraks apart and remount their tether sensors in a row, to capture a koto player's pressing and pulling of the strings.
Rebuild a Gametrak into an Ondes Martenot-style ribbon controller: a finger ring on a loop of cord sets the pitch, and pressing the board sets the volume.
Swap the Gametrak's own circuit board for your own microcontroller, wired or wireless.
A round, upright harp of Gametrak tethers bound by a movable ring, for groups of players from young children to skilled musicians.
From the paper Musical Applications and Design Techniques for the Gametrak Tethered Spatial Position Controller (SMC 2009), and other Gametrak instruments. The Gametrak was based on golf swing tracking. It is no longer made, but can be found on eBay.
Activities that change where the parts of an instrument or controller sit, relative to the player and to the space around them. The Gametrak began with one arrangement: its "basic ergonomic design was influenced by gaming applications involving the swinging of clubs (golf), bats (baseball) bowling or skiing", with its sensors "housed in a weighted box that is normally placed on the ground" (SMC 2009). The Gametrak activities here rearrange it. Others place the sensors where the hands can reach them: the kalimba's tines, each long enough to put its free end within reach of the thumbs; the sensors tried on a guitar's body, to find which parts a player can work while playing the strings; the Tablo's ring of petals, split into two halves, one for each hand. They build on the structural view of instruments in The Fingerboard Instruments: Reframing Lutherie without Strings (McGill, 2010).