I've built my own strobe tuner.
Guitars, basses or synthesizers can be plugged into the tuner at the rear panel.
The input signal is amplified and compressed with analog circuitry. Further on it's fed into a
voltage to current converter that drives a LED which lightens the spinnig wheel.
The wheel is made out of paper at which i printed the strobe pattern.
An BLDC motor ripped from a cdrom is used to spin the wheel with the required rpm.
BLDC motors require three phase current which is generated by an ATMEGA8515 controller in my design.
The motor is used in synchronous mode without feedback which reduces complexity.
To attain high frequency resolution i used a phase accumulator oscillator that runs in the interrupt
routine of the ATMEGA controller.
Frequencies of equally tempered scale are stored in the Controller and have to be selected manually.
Automatic note selection would be desirable. Perhaps i will have time to implenent it into the system.