Keys can also be assigned to start and stop “Riffs" that might be programmed as part of the preset.
Early versions had LEDs and photodiodes on a circuit board below a reflective drum membrane.
Later versions used capacitive technology to sense the deformation of the grounded graphic overlay.
Other inputs include a footswitch, a footpedal, and a memory card slot for backup.
Thunder has a sophisticated built-in user interface, employing an 80-character displaying menus that get selected from small hexagon touch keys below the display and data entry using the “Thunder” strip below that.