[sdiy] BPM clock generator?

[Matthew Smith]

Quoth Karl Ekdahl at 2009-02-01 17:13...
> I'm in need for a couple of digital BPM generators with Gate or Trig outputs, anyone knows where i can find schematics for one? I don't need anything fanct, just a LED interface with a "+" and "-" button to change BPM.
> 
> On a related note i'm also looking for simple digital oscillators where i can through a simple interface enter the exact frequency, any thoughts highly welcome!

Both jobs very much suited to a microcontroller.  If I were doing this, 
I'd rig something up with an ATTiny2313 but if you are looking for 
something more ready-to-go, Arduino would be my suggestion as the 
hardware is all there for you (excepting any level translations if your 
gear isn't using 0V,+5V.)

Either way, for something this simple, I would use a series of 3 (for 
the BPM generator) or 5 (for the DO) BCD encoded switches as the user 
interface - nothing else.

If the digital oscillator only needs to put out a square or pulse wave, 
both items could be the same - you could just have a switch to specify 
whether the input should be interpreted as Hz or BPM.

Software would just need to scan and sum the values of the BCD switches 
then toggle an output pin using a combination of hardware timers and 
software delays.

If you are not into programming microcontrollers, you may well be able 
to find projects with code that can either already do the job or at 
least be modified to so.  If you aren't a programmer, now is a good time 
to become one ;-)  (Ducks to avoid the flack from all the pure analogue 
guys ;-)

If you aren't in a hurry and are interested in pursuing this route, 
contact me off-list and I may be able to assist on the coding side.

Cheers

M

-- 
Matthew Smith
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