MIDI Pedal Wizard

MIDI Pedal Wizard is a tool that allows you to use MIDI pedal controllers to play notes and chords on MIDI hardware or virtual instruments. It's for the solo guitarist that wants to add bass, piano, organ or synthesizer parts to his performance. Or the keyboardist whose two hands are already occupied and wants to play a third part. Or the sax player that wants to provide his own accompaniment. Any combination of MIDI footswitch controllers which send control change messages (controller value 0 for off, and 127 for on) may be utilized. The power of MIDI Pedal Wizard lies in the ability to assign note sequences to MIDI controllers. The foot controller is used to step through the note sequence with each tap of the controller playing a note or chord. Thus a single controller may be used to play a walking bass line, a chord sequence, or whatever you need behind your main instrument. An integrated note sequence editor lets you build and modify your note sequences using its virtual piano keyboard or alternatively an external MIDI keyboard controller.
Requires:

1) A footswitch controller that sends MIDI control change messages. It may be either latching or momentary type but must send value 127 for "on" and 0 for "off." It could be a sustain pedal connected to a keyboard, a drum trigger pedal connected to a pad controller, or a dedicated device. Bluetooth devices such as iRig Blueboard and Positive Grid BT-4 may be also used in conjunction with their dedicated apps which translate bluetooth signals into MIDI messages.

and 2) A virtual instrument app which receives MIDI note messages -OR- a hardware MIDI keyboard/sound module connected to the iOS device via a MIDI interface or USB cable + camera connection kit.