This is an incomplete experiment, but I wanted to test the principles from Arduino Top Octave Generator and Arduino Top Octave Generator – Counter Experiments in practice a little more.
You may recall the basic idea here is to generate 12 tones using an Arduino and then use binary counters to divide them by 2 several times to get lower octave equivalent tones. The Arduino is generating tones all the time, so all any keyboard has to do is connect the appropriate tone to an output.
This takes two counters and shows three octaves for three different keys working, but it is using a very primitive output stage. So in this case, the warning below is very relevant more than ever – as I’m not an electronics person, I don’t know what this will do to your Arduino or amplification…
Warning! I strongly recommend using old or second hand equipment for your experiments. I am not responsible for any damage to expensive instruments!
These are the key Arduino tutorials for the main concepts used in this project:
If you are new to Arduino, see the Getting Started pages.
Parts list
- Arduino Uno
- 2x SN74HC393N binary counter (more optional)
- 9x button switches (more optional)
- 9x 10kΩ resistors (more optional – one per switch)
- Amplification or output device
- Breadboards and jumper wires
The Circuit
This diagram shows the theoretical circuit we’re aiming for. I’ve only built a three-octave, three-notes-per-octave version using two 74HC393s and 9 switches (and resistors). I have no idea if the full thing would work, but the basic principles are sound.
I’ve move the resistors from the first breadboard over to each switch. Together they form a passive mixer. It works for my 9 switches, I have no idea if it would work for 48!
Code
There is no additional code required. This is all still running off the Arduino Top Octave Generator.
Closing Thoughts
I’m still interested in knowing if it would be possible to build a full four-octave keyboard off the back of these principles. I’m sure it is, but my electronics knowledge is not sufficient to know what to do to ensure the Arduino IO pins don’t have too much current drawn, that the counters are within their specification and that the output mixer stage is suitable for plugging into audio equipment.
If anyone is feeling brave, and actually knows what they are doing, and gives it a go, do let me know!
Kevin
Simple DIY Electronic Music Projects 