Last night, I printed my own MIDI controller. The secret ingredient was Overlay Designer, a new software feature for the Sensel Morph (sensel.com; $299). Morph, as the name implies, is a highly customizable touchpad and a terrific platform for DIY projects. It’s beautifully designed from brushed aluminum, about 6.75 inches tall, 9.5 inches wide, and a quarter-inch thick. The top surface holds some 20,000 pressure sensors that Sensel says can detect 32,000 levels of force. That’s responsive enough to handle everything from paintbrushes to drumsticks.
To keep you oriented, the Morph offers silicone rubber overlays ($35 each) with control layouts ranging from computer keys to drum pads (see Figure 1). Each overlay has a unique arrangement of embedded magnets that snap it into place and reconfigure the base to send new types of data. (You can also use Morph without an overlay.) Like an iPad, the Morph detects multiple fingers at once. LEDs glow gently to show where you’re touching.
The Morph transmits over USB or Bluetooth and includes a rechargeable battery. It can’t play iOS softsynths over USB unless you use a powered Lightning adapter or USB hub, so the wireless option is handy. An optional Developer’s Cable ($19) breaks out the USB port to four pins you can connect to an Arduino or Raspberry Pi.
I’ve been messing with Morph since Roger Linn lent me his system last summer, but it really clicked for me when Sensel released Overlay Designer and a transparent skin called the Innovator’s Overlay. To create my custom MIDI controller, I drew buttons and sliders in a graphics program, printed the page, and slid the paper under the overlay (see Figure 2). I then exported the page as an image file, loaded the image into the SenselApp editor as a background, drew control zones on top, and downloaded the control map to the Morph (see Figure 3). Interestingly, Roger built a prototype of the LinnStrument using a similar approach, as you can see in his 2010 video: youtu.be/AoAOx97G8ew.
Developing controllers on paper makes it easy to refine them. Some of the buttons on my initial layout were too close to the edge, causing double triggering. So I nudged the graphics inward, printed another page, and raised the trigger threshold in the editor. Next, I made a variation with drum pads instead of keys. (The Morph memory holds only one map per overlay, but downloading a new map from the editor takes seconds.)
The editor also generates STL files so you can create tactile controls on a 3D printer. (The Innovator’s Overlay has a recessed area on top to hold them.) Sensel has tips on materials and printing services on its site. For my paper layouts, I set my artboard to 238mm x 140mm, with 5mm inner margins on the sides, 12mm on top, and 10mm on the bottom.
I’ve only scratched the rubbery surface here. Check out Tim Thompson’s amazing audiovisual instrument built from four Morphs at youtu.be/3_s2P7gMRm0.