Strobe Tuner Webpage
Updated Feb 6, 2005
This is the simplest of the strobe tuners I am doing. This one, is in fact, a real strobe tuner. And you will probably notice that there are indeed no moving parts in this thing, so you may well ask how is it a strobe tuner.
If you look on page four of the schematic you will see the circuit for the phase accumulator that provides the reference frequency for the strobe. Phase accumulator is just a fancy way of saying counter. It is a special counter in that the counter will increment by the value that is place in the frequency register (U8, U11, U16). The output of the phase accumulator, or rather, the upper five bits, go to a decoder that will decode the 5 bits into one of 32 outputs. Each output will then select one of 32 LEDs that are arranged in a circle.
Now on page 5 is the analog input circuitry that interfaces between a microphone and the circuit that generate a constant current. The output of the constant current source is connected to all 32 LEDs. Now what happens is if there is enough current generated to light the leds, the one that will light is the one selected by the current value that is in the phase accumulator. If the frequency that is being generated by the phase accumulator matches the frequency of the input signal, you will see a pattern in the LEDs that will appear to stand still. If the frequencies differ by say 1Hz, you will see the pattern rotate in one direction 1 revolution per second.
Feb 6, 2005
Just to let you know that something is being done on this, I did do a bit of work on the PC board layout this weekend. I am hoping to finish this up by the end of the week. It is going to be a fairly good size printed circuit card, but it should be fairly quick to route as the circuit density is fairly low. I will keep you posted, if you happen to be watching this page...
Strobe Tuner II
Strobe tuner II is going to be different in that the circuit will be able to process the in coming signal and tell you how far out of tune it is. It will also be able to communicate with a host computer so that data can be logged. This is being designed mostly for use in tuning the VCO’s in my Synthesizers. There is more to come on this later. I want to get the first one working first, since many of the ideas in I are also going to be needed in II.