I would like to advise that I have devised a key contact system that uses Hall Effect sensors.
This system eliminates the hysteresis effect common with the use of magnetic reed switches and very basic Hall Effect sensing. This system gives 100% reliable keying, with no ‘contact bounce’.
Main features:
1. Easy to fit.
2. Very precise measurement of key position.
3. Can send key-on, key-off and velocity data.
4. Multiple ‘on’ point sensing, providing ‘second touch’ output.
5. Direct MIDI output on Channels 1-16.
6. Very little wiring. Only 15 wires to encoder plus one 5V DC power cable to first PCB.
Description.
System works utilising Hall Effect sensors
One PCB per octave, top octave has 13 sensors.
Other numbers of keys are possible.
PCB is 30mm wide, which make it easy to fit on any kind of keyboard.
System can ‘sense’ movement in either direction, decreasing or increasing distance of key surface to sensors. Circuit board can be mounted in almost any place on keyboard
Small neodymium magnets 3mm diameter and 1.5mm high are mounted on keys using epoxy glue, super glue or similar. Movement of keys is converted to digital format, with resolution of approx. 0.04mm.
No ‘drilling’ of holes is required for magnet fixing. It is enough to maintain similar distance between sensors and magnets.
Each printed board (octave) is connected to the encoder with one twisted pair cable. Digital data is converted to MIDI messages. Adjustment of firing point, measurement velocity is possible
Because adjustment of contact is only done digitally it is very easy for complete keyboard or for each key to be ‘adjusted’.
As system can have multiple ‘On’ points and it can detect ‘velocity’ and send ‘second touch’ data.
Tests have shown that in the case of keys with sheet metal frame (covered with plastic, such as found on many commercial keyboards) the magnets will hold their position with their own magnetism.
This new system is about to be fitted on two types of manuals, wood core and metal frame.
I will shortly post further details and photos of a complete keyboards fitted with this system.
tomasznowak690@gmail.cominfo@pipeorganlogic.com