typical version with battery holder

This is the "brains" of MIDI keyboard. It is powered from 3 AA cells or external power source (3-5V). Keys must be groupped by 4, i.e. one pole of 4 keys in a row connected together, other poles of those keys go to their corresponding pin, so 5 wires go from the board for each group of 4 keys. Keyboard is connected using 50-pin IDC. See the simplified pinout of the board and detailed connection diagram. To use controllers, solder potentiometer (10-50kohm, linear taper) to appropriate leads: 1-taper, 2-low side, 3-high side according to simplified pinout. If any controller is not to be used, short wire must be soldered between leads 1 and 2 to prevent any unwanted MIDI messages generated by floating controller input. But best way is to specify at order that less than 3 controllers are planned.

Features:

• 37-keys range, or 36 if 2 keys for MIDI channel change (+/-) required. 40 keys also possible, but without transposition and channel change.
• unlimited transpose up/down, i.e. it wraps around when transposed over 0-127 MIDI note range. Pressing both transpose buttons simultaneously resets transposition to default note.
• MIDI channel change (up only, or up/down)
• pitchbend, modulation and volume controllers (potentiometers not included), or any other MIDI controllers on your request
• 1 jumper configures it to work in battery mode (enters power down after some time to save battery) or external power mode (works all the time at full speed).
• cable with pannel mount metal-cased DIN5 MIDI socket
• when used with direct PC GamePort connector it requires no power supply.
• dimensions: 95x40mm (3.7''x1.6'') without battery pack
• more marketing talk

How to order

The board is available for 50EUR including shipping worldwide. When placing order, you choose:

1. Keyboard range, i.e. what are the note numbers assigned to each key. They don't have to be continuous, and can also duplicate. Transposition moves all keys up and down. Default is countinuous from MIDI note 36.
2. Transposition step size in number of semitones. Default: 1 semitone.
3. How many (1, 2, 3 or none) controllers will be used, and what they should be. Default set: pitchbend, modulation and volume.
4. MIDI channels of each controller. They can be either associated with keyboard's channel, or use any other channel (not affected by channel change feature).
5. connector type: standard MIDI socket as shown above, or PC Game Port
6. legth of the cable on MIDI DIN socket
7. 3 potentiometers for controllers may be included for additional 5EUR.