I have the tiny PC board  and things are almost working.
I am still waiting on a few chips.

I had a bit of trouble with the Atmel ZBasic
computer board. I am not sure what happened but
I sent it back to the manufacturer and they are
checking it out. They promised to repair or replace.

http://www.zbasic.net/

It stopped over writing the program that was in it.
It still worked but I could not modify the program
that is in there now. Perhaps something to do with
disabling the real time clock but the jury is still
out on that. I was told that was possible and I did it
but it could have had some unintended consequences on
the over write software.

There is no real need to disable the real time clock
as the time critical stuff is done by this
module and one or two others. One of which is the ignition
system. This modules just reads a mag sensors on the flywheel
teeth and counts them in a fixed time period. It notifies
the computer when it has a valid number for RPM and the
computer reads it and restarts it to count teeth again.
It happens every .6 seconds. In theory it is accurate
to one RPM but of course there may be least significant
bit jitter common in digital counters. In other words
it could be 7489 or 7488 RPM.

Video coax cable is used to connect the mag sensor near
the flywheel to the board to cut down on possible
interference from the CD ignition system.

BTW Pedro, this system will be ideal for your four rotor
as it is entirely modular. 1,2,3 or 4 rotors it does
not care. Just add CD ignition modules and one of these
RPM counters and you will have a complete engine control
computer with all engine parameters sent out for
real time display and recorded on a cheap net book
computer. The same net book computer can be used
to program the system.

The software is programmed in BASIC so any child
can learn to program it. It will be entirely
open source so anybody can upload and download
programs on here.

Over all cost will be half of what most systems
cost.

The ignition system is coming along as well.
More about that latter.

Paul Lamar