Few-wire signal transfer

[lorylaci]

I was thinking about the following:
If the analog signals would be multiplexed in the drumpads then there would be enoguh three wire to transmit all signals to the drum brain, where there would be no need of demultiplexing. I have the following theoretical solution:
1. wire - ground
2. wire - clock: giving main clok frequency F and giving big impulses for every 32rd amplitude max
3. wire - signal
The electronic in the drum pad would do the following: multiplex the signal to the clock main signal,for the channel programmed with a siwtch, channel would be separted by counting from the clok imppulse n time.
The supply would be derivated from the clok wire, (like phantom powering in audio lines) with resistor+inductor+ cond to ground.

I'm currently working on the expanding of my home-made drum rack (with all wires taken inside rack cilinders). I have few space for more cable, and these lot of cables giving me a headache. I don't know if this theoretical method is even clear for you guys, and I don't know yet that it can be done (I'm currently wokring on designing schematic and later simulations).
Thee wire could be easily layed out in rrack, thick wires could be used, stanadrd stereo jack connenctor 8or even XLR) can be used (so current standards can be applied).

If anybody interested, please tell. With proper rack design this could bring Megadrum to a more complete "product"

[Ken Forgettable]

Have you looked at the frequencies of the haed / rim PZTs?

As the rim (shell) PZT is mounted vertically on the shell then the frequency is at least twice that of the
horizontal head PZT. This means it is possible to distinguish the head from the rim just by frequency - so
both channels can go down the same signal wire...

There is room for a third control signal there too (aka hihat DC contol) with a bit of tinkering.

.... you could have a four piece kit with hi-hat and three cymbals without any multiplexers if you asked
for it ...

I was thinking more along the lines of phantom powering - like 5v at the tip man.

[lorylaci]

Here is my idea for schematic attached.
It can be further impruved, the scpecial clock signal enabels sincronising of all transmitters in all drum modules. The simple counter IC makes the channels, and switches the signal to the channel with a fet. With a rotary switch or whateever you can choose the channel.
Powering will be made from clock wire with a resistor in series and a capacitor just like phantom powering. (not much current would be needed)
With this there would be no need for multiplexing in drum brain, the whole singel wire can be AD converted and with the clock signal can be separated. And a three wire system would be enough. Three wires could be easily taken inside rack cilinders, and st. jacks can be used as connectors, all of them connected parallel. (even two wire can be used, as rack for ground connecting).
I have a rack design, from components easily accessable in my country (and maybe in foreign countries). My design would really make use for big sets, where even the built in cables of an MDS12 is not enough, and where lots of cables is really a mess.
I was even thinking about wireless solutions.

[Ken Forgettable]

... I was even thinking about wireless solutions.

I think reliable wireless would be too expensive - what about two wire differential signaling like the CAN bus?

Anyway what about doing a test with this, record the output using a sound card (1vpp) and lets take a look...