This should be easy to replicate in firmware on an Arduino, right? Microcontroller Non-Solutions If we had to implement this in silicon, we’d build up twelve 9-bit counters, all driven by the same 2 MHz master clock, and cause them to reset when the right counts were reached. But what if you want to repair a 1970s organ that used them? You might be able to order expensive old-stock spares, but where’s the fun in that?Īlmost all of the TOGs took an input frequency derived from a 2 MHz crystal oscillator circuit and provided twelve or thirteen square waves of the right pitches by dividing this input frequency by factors from 239 to 478. Providing an accurate set of twelve reference pitches is the job of the top-octave generator (TOG) chip, a part which isn’t made anymore. Dividing a frequency by two lowers its perceived pitch by an octave which meant that, if you could accurately generate one pitch for each of the twelve tones in the scale, you could use flip-flops and divide down to cover the entire keyboard. In particular, these designs leverage the ability of a flip-flop to take an input frequency and divide it by two easily and cheaply. (At least for mass-market instruments: a real pipe organ in a big space is still a delight to hear in person.)īut for a brief period of time between the tonewheel and the VLSI eras, there was a decade of home organs that were designed with the readily available wonder technology of that era, discrete logic ICs. By the 1980s, all of this sound generation could be contained in a dedicated IC, ending the era of the giants. A Hammond is still not a small machine, but it was positively compact compared to the pipe organ. Then along came the Hammond organ, which from 1935 to the mid 1970s made sound by spinning metal disks with periodic cutouts in the presence of an electronic pickup. Pipe organs make sound by vibrating air in tremendously large tubes, one per pitch. Can you help repair his organ with a minimum amount of expenditure and hassle? All we need to do is produce twelve, or maybe thirteen, differently pitched square waves simultaneously. ![]() So we’re passing the buck on to you, dear Hackaday reader. ![]() I replied “I should be able to get that done with a single Arduino” and proceeded to prove myself entirely wrong in short order. He had found a complicated but promising circuit online, and was wondering if there was anything simpler. Case in point: wrote in with a busted 1970s organ in need of a new top-octave generator, and wondered if we could help. Be warned, the Poser Debut software might have issues with the serial number, but Smith Micro is very good at fixing it for you.One of the great joys of Hackaday are the truly oddball requests that we sometimes get over the tip line. You're supposed to get what is pictured on the box, 3 pieces of software (Poser Debut, Anime Studio and Manga Studio), and I do believe you're supposed to get both PC and Mac versions with serial numbers for all products. ![]() Be warned, the Poser Debut software might have issues with the serial number, but Smith Micro is v…
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