This design is based on the requirements of a 88 Note Velocity sensitive Fatar keyboard with MIDI Aftertouch. The keyboard is arranged as two matrices of 8x5 (40), for the Left Hand Bass range and 8x6 (48), for the Right hand Treble range, for a total of 88 (40 + 88) keys.


The 40 note 8x5 (40), for the Left Hand Bass range range is from A0 (MIDI Number 21) to C4 (MIDI Number 60), and the the 48 note 8x6 (48), for the Right Hand Treble range range is from C#4 (MIDI Number 61) to C8 (MIDI Number 108). The MIDI Channel is preset to MIDI Channel 1. However other values for the MIDI Channel and the note range can be pre-programmed into the firmware. The encoded switches are wired via IN4148 diodes. There are 2 switches and 2 diodes associated with each key. The switches are called the Break (BR) and Make (MK) switches. When a key is pressed the Break contacts close first and then the Make contacts close, as the key is further pressed. The difference in time between these two switch closures provides the time which is used to calculate the MIDI Note On velocity for each keypress. Also the MIDI Note Off velocity is calculated in a similar way when the key is released. This unit can be connected to new keyboards or it can be used with an older non-MIDI keyboard by using magnetic/reed switches, or Hall Effect devices, to isolate the old and new scanning circuits. This will allow the older keyboard synthesiser to continue to operate as normal while also providing a MIDI output.

This unit can work in standard MIDI mode and via the USB connection, at the same time. It defaults to standard MIDI Baud rate of 31250. By replacing the original firmware on Mega8u2/16U2, the Arduino will act as USB-MIDI device (Standard Midi Class), you do not need to install additional device drivers on Windows, MaxOSX, and Linux, as the firmware acts as a device of Standard Midi Class. It will automatically install on the system as an Audio USB Device.

Power Supply:

External power can come either from an AC-to-DC adapter or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack.

The board can operate on an external supply of 7 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts.


The MIDI/USB 88 Note Velocity Keyboard Encoder Unit consists of:
  • An assembled MIDI Arduino Board, including a suitable pre-programmed microcontroller,
  • The MIDI channel is preset to channel 1,
  • The start note of the bass pedal encoder is from MIDI note A0 (MIDI Note 21),
  • Other MIDI channel and start note values can be pre-programmed into the firmware on request,
  • A 2.1mm power socket, and associated LED,
  • A MIDI 5-pin DIN output socket and associated series resistors.
The MIDI/USB 88 Note Velocity Keyboard Encoder unit requires:
  • a 9v battery or equivalent DC power source or via the USB socket
  • 88 suitable key-switches or magnetic reed switches


The MIDI/USB 88 Note Velocity Keyboard Encoder Unit Resources:



PRICE:  €79.95

After clicking on the 'Add to Cart' button, just complete your order on the Paypal site, where you can select the required quantity. Also the appropriate shipping cost is calculated and added. However you may still cancel or adjust your order, at this point.