odibrom
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Don't forget the Cycfi pickup system...Pretty much all available pickups are either magnetic, or piezo saddles. Then there's the family of optical pickups. Light4Sound, LightWave, oPik, but none of these have made any notable market penetration (as far as I know).
The Fluence pickups being layered PCBs is quite a revolutionary change, no matter how similar or unique the rest of the pickup system may be to other active pickups.
I use guitars with synth pickups... and can change the tuning and type of guitar at the flick of the switch. The technology is out there, but guitarists are hung up on trying anything new.
I'd love to experiment with MIDI guitar if I hadn't to double the onboard and outboard hardware or carry a PC+audio interface everywhere I'd need to go... it quickly gets super expensive...