May 4, 2010
News - July Caption Contest
about 2 years ago
Fred Stark : The (Soldering) Iron Man.
about 2 years ago
I will add - this was extremely useful for understanding the functioning of the opamp circuit on this board - it has almost the exact same circuit as used on the BOB (about ¾ of the way down the page)
OK - I also got this to work as a rudimentary SPL (decibel) meter. I used a picaxe chip 18M2.Code below :
readadc B.4, b1
if b1 > 140 then
;sertxd (“b1 is ”, #b1, CR, LF)
You may have to play around with that 140 number depending on if your kids are singing in the background or not LOL
The VCC for the BOB needs to be the same VCC for the picaxe chip (I used 3.3V) and the ground for the picaxe and the BOB needs to be tied together. For some reason connecting the gnd for the picaxe and the ground to my scope made a mess of the signal - I think my picaxe gnd has a lot of junk flowing into it.
Hook the Aud connector to the picaxe pin B.4 in the example above.
I also hooked an led (w/ resistor of course) to C.6.
If you program your picaxe from the Programming Editor then stand near this and clap or make a loud noise you will see the led flash and in my case since I had lights on my usb connection I see the usb lights flash too AND in the Programming Editor the debug window will open showing u the ADC value, from 140 up to 255. The commented out sertxd line is if you want to see a serial message instead of the debug window.
My next attempt will be to triangulate on a loud sound to determine direction using 3 of these, luckily I got 4 of these as #4 was DOA.
Anyways, this does work, at least for me, altho it was very helpful having a scope to see the signal because on the Aud out if you hook up a multimeter you will NOT see anything other than a fixed voltage that does not change. The real analog signal this puts out needs a scope or similar to see.
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