There is also a good explanation of what is happening here
It is quite cool, so I am planning to make a more permanent installation and add cv to the knobs, but I was wondering if you have ideas how to make it a little bit more ‘predictable’ or ‘musical’, so I can integrate it a little bit better with the rest of my modular…
I was thinking about making another knob for the overall velocity of the pattern and have a pitch and maybe a kind of trigger and a switch to make it play just a short expression?
What do you think?
Without going too deep down this rabbit hole of 8-bit music, I would suggest that you investigate the possibility of using a pitch table linked to a linear pitch potentiometer. By introducing an exponential pitch distribution into your chiptune equations you may, within the limits of the genre, be able to make the sound more musical.
That sounds interesting! I will see if I can do that!
I noticed that maybe what I want it to be more in sync with the rest of my KOSMO… So, maybe I need to add some kind of sync or clock…
Hell, I am not even sure what I want it to be XD! I think I wanted it to be a bit of background bleep-blob, like Sam uses sometimes to connect different parts of tracks, or just as interesting addition to the ‘main’ melodies. I think he uses the benjolin for that(?) Maybe I just need to try more and simply practice
If you want a lot of inputs, go for a different Arduino (or another board altogether.) Arduino Nano is cheap, ubiquitous and well supported. There are other, far more powerful boards that won’t break your pocket.
I looked over the code and it doesn’t look like it’s set up to take trigger or CV signals. (It doesn’t sound like that’s the idea either.) Maybe they were just using the Eurorack’s 5v bus line for power but they play it as demonstrated in this video or something.
In the original code there are no gates/triggers included, so you need to think about how to implement them (and also what they should do exactly). Then you can just use any free pin you want.
For CV I am planning to use this circuit (from mutable instruments):
Adding this as a reference for myself on how I want to add the gate/trigger. The manual button will also be connected to the GATE label and also send it to ground.
In this circuit the GATE voltage will vary from ca. 3.3 volt if the transistor is not conducting to a voltage near 0.5 Volts or maybe a bit lower if the transistor is conducting.
Adding an LED between the resistor and the GATE output will lower the high voltage by the voltage drop of the LED which can be several volts. So then your gate will not likely be functional anymore. It is wise I think to use a second transistor (any small signal NPN transistor will do, e.g. BC547, BC548, BC549 etc) for the LED and connect its base via a 100 kOhm resistor to the TRIG_JACK_1. The 10kOhm connected to the collector of that 2nd transistor I would then reduce to 1k or lower depending on how bright you want the LED to shine. Note that some LEDs have a forward voltage near 3 Volts, so then either hook them up to a higher voltage than the 3v3 OR find a LED with a lower forward voltage.
You can drive a modern LED quite hard. If you get really worried and you have another low value resistor, solder it in between the diode and the original low value resistor. But if your LED should die in action you can always replace it. No worries.
If you know the maximum current the LED can take, then you can calculate the resistor value quite easily. Assuming the transistor is an ideal switch and has not voltage drop: R = (5 V - forward_voltage_of_led) / forward_current
Obviously the transistor must be able to conduct the current you choose. But given that modern LEDs give off quite a lot of light ( often more than you want ), 5 to 10 mA should be enough. So e.g. a LED with a 2.5 Volt forward voltage at 10 mA would need (5 - 2.5) / 10e-3 = 500 Ohm. Given that the transistor is not an ideal switch and will cause a small voltage drop the current will be a bit lower. Mind you, if the transistor is only switched on by a trigger pulse, then the LED will be relatively more off than on so the transistor will not get warm at all, nor the resistor.
I am looking for a mistake in my circuit, because one of the potentiometers does not go up linearly, but even goes a bit down towards the end (when I turn it clockwise)… I measured a few things and then noticed that I always have 5k resistance between my 5V and ground! I removed almost all of the components from my little stripboard looking for a short and then I noticed that it is from the LM7805! It has some internal resistors, apparently 5k, between its output and the ground pin! I can see it in the datasheet! Should have looked there from the beginning, now I feel stupid again! xD
Still need to find the reason for the strange potentiometer.
Did you get this to work? I stripboarded a glitch master together this weekend and it did not work. Writing some test code showed that the project assigned the serial pins to an LED. Reassigning that pin fixed the conflict. It also showed that one of the switches was shorted. It works now!
