Olin Lathrop wrote: > 'William Chops" Westfield ' > > I assume the two strobes are fired 180 degrees apart. > > > > I am not seeing how it behaves differently than a single LED operated > > at twice the target frequency... >=20 > I don't either, but they have two LEDs there that are driven from differe= nt > pins. Maybe the way the hardware is, it's easier to drive them separately= .. > More likely whoever did it wan't that thmart. Notice this wasn't a commer= cial > product. The schematic was poorly drawn and the board was clearly homemad= e. > Not thinking about one LED being able to do this fits right in. This is getting really tedious ... is it really necessary to denegrate a person who isn't even on this list, just because they don't do every projec= t up to your professional standards? Obviously, you know a lot about electrical engineering, but not much about making music in general, or playing the guitar in particular. I thought the design was very clever. First, note that it says quite clearl= y on the website that the PCB is itself intended to be used as a plectrum, to pick the string being tuned. As such, the two LEDs are held physically clos= e to the string being tuned (by the other hand). They'll illuminate two nearb= y spots on the string, which, because of the out-of-phase flashing, will generally appear to be moving in opposite directions whenever the string is out of tune, quite easy to see. Since the flashing isn't perfectly 180 degr= ees out of phase, the user (with experience) gets a clue as to whether the stri= ng is sharp or flat, from the pattern of the motion. When the movement stops, the string is in tune. I'm guessing that this makes the whole process very quick and precise, important in a peformance situation. -- Dave Tweed --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .