MIDI interface for tonewheel Hammond organs (B3 & C3 models)

These PCBs are designed to fit underneath the B3 or C3 Hammond organ keyboard. The mounting lines up with the existing assembly, so it can be mounted without any alteration or damage to the existing instrument. The boards plug into each other to form a chain of 3. They detect all keys pressed, including the pre-set keys that can be used for digital pre-sets in a sound module if desired.

This PCB provides full keyboard velocity sensing for each key, and produces an industry standard isolated MIDI string that can be connected to any MIDI device or sound module.

This is an entirely invisible and passive set of PCBs that sit under the keys. The mounting holes line up exactly with the existing chassis bolts. It does not effect the normal operation or feel of the Hammond, and does not require any mechanical or non-reversible modifications to the instrument other than disassembly, installation and re-assembly. Although a very time consuming installation, it also presents an excellent opportunity to undertake inspection, service, preventative maintenance, and a thorough cleaning of the Hammond organ. 

The key press and velocity detection is performed optically (non contact) by reflected infrared light off the underside of each key.