JonDent - Exploring Electronic Music

Saturday, 1 April 2017

Buchla 200 - Friday night patch

Just having fun with the 200.
That 296 filter is wonderful.

#buchla296 #programmable #spectral #processor #modularsynth #vintage

A post shared by jono (@dj_jondent) on Mar 31, 2017 at 4:43am PDT

Micro Granny - Basl Instruments

Thanks Andrew for bringing this over

#bastl #microgranny #mg #sampler # Synth #granular #synthesizer

A post shared by jono (@dj_jondent) on Mar 31, 2017 at 3:17am PDT

Its a monophonic granular sampler. It reads wav samples from microSD card and applies granular algorithms to them. You can also adjust start, end, sample rate (tuned or free run), crush and envelope (attack release).

It's all 8-bit.
Uses a microcontroller / Arduino platform.

Korg PS 3200

The lovely Sounds of the Korg Ps 3200

Andrew brought his Future Retro Zillion sequencer yesterday
so we decided to test it out on the Korg.

#korgps3200 #virusinstaller #synthesizer #modular #korg #vintage

A post shared by jono (@dj_jondent) on Mar 31, 2017 at 2:56am PDT

Wednesday, 29 March 2017

Buchla Preset card - DIY mixer for 208 easel

One of the best things about the Buchla Music Easel is its program card.
It's really not just for presets ... esp the original card invented by Don Buchla back in the 1970s.

I'm guessing he may have wanted us users to experiment with electronic circuits.
Why else would Don have placed a mini "breadboard" with +/- 15V rails on the program card?

The Buchla SILI-CON CELLO from 1978 is a good example of his use of breadboard circuits in a fully
functioning system. It's a shame the current BEMI program cards have removed this homage to the age of DIY electronics.

This is my latest use of the card: a DIY mixer.
(The 10U system doesn't have a dedicated mixer).

The circuit is very simple.
Just one dual op-amp (TL072)

It's a basic unity gain inverting configuration. In the first half the 4 inputs are mixed into the inverting input of a op-amp. Since the output signal from this op-amp is inverted, the 2nd op-amp re-inverts it.

Power goes to pins 4 & 8. The unmarked resistor on the right is 1K

Thanks to Ken Stone for the original circuit. and Justin from MetroModular for his advice.
Ken's schematics show the possibility for using this as a CV mixer & attenuverter.

Breadboarding the circuit. Just two inputs on the left without pots.
It works on +/-12V above and +/-15V below.

Might try building a mixer using the OPA2134.
It's pinout is the same as the TL072.

Saturday, 25 March 2017

Momentary push buttons - Turning a LED on with a button - arduino

Momentary push buttons

These are really common in arduino projects

It's a basically 2 switches

The vertical leads are internally connected prior to pressing the button.

Pressing the button will close those switches at the top & bottom of the switch.

The circuit below, doesn't use any coding. The arduino board is simply a power supply.

Code 1

This is a basic code using pulldown resistors and a switch.

It's a complicated way of turning a LED on.

The idea is to use software, rather than hardware to turn the switch on.

Black is ground.

Red is +5V

When the button is not pressed, the pin 2 is connected to ground (via the resistor).

Pin 2 thus reads LOW

When the button is pressed, Pin 2 is connected to +5V, and thus reads a HIGH.

Here is the code:

//----------------..........................................

/*
Button

Turns on and off a light emitting diode(LED) connected to digital pin 13,
when pressing a pushbutton attached to pin 2.

The circuit:
- LED attached from pin 13 to ground
- pushbutton attached to pin 2 from +5V
- 10K resistor attached to pin 2 from ground

- Note: on most Arduinos there is already an LED on the board
    attached to pin 13.

created 2005
by DojoDave <http://www.0j0.org>
modified 30 Aug 2011
by Tom Igoe

This example code is in the public domain.

http://www.arduino.cc/en/Tutorial/Button
*/

// constants won't change. They're used here to set pin numbers:
const int buttonPin = 2;     // the number of the pushbutton pin
const int ledPin = 13;      // the number of the LED pin

// variables will change:
int buttonState = 0;         // variable for reading the pushbutton status

void setup() {
// initialize the LED pin as an output:
pinMode(ledPin, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}

void loop() {
// read the state of the pushbutton value:
buttonState = digitalRead(buttonPin);

// check if the pushbutton is pressed. If it is, the buttonState is HIGH:
if (buttonState == HIGH) {
    // turn LED on:
    digitalWrite(ledPin, HIGH);
} else {
    // turn LED off:
    digitalWrite(ledPin, LOW);
}
}

// -----------

Basic program # 2

Slightly different way to do the same thing.

The pushbutton is part of the pulldown resistor detection system

pin 9 reads either a HIGH or LOW signal.

Its the input

When the button is not pressed, pin 9 is connected to 5V through the resistor... Thus HIGH.

Digital pins are instructed to stay LOW and don't put out 5V to light the LEDs.

When the button is pressed, the opposite occurs.

Here is the code

// ---------------------------------------------------------

int buttonstate = 0;

void setup()
{
pinMode(9, INPUT);
pinMode(13, OUTPUT);
pinMode(6, OUTPUT);
}

void loop()
{
buttonstate = digitalRead(9);
if (buttonstate == HIGH) {
    // when not pressed the pull up resistor is on
    digitalWrite(13, LOW);
    digitalWrite(6, LOW);
} else {
    // helpful single-line comment here
    digitalWrite(13, HIGH);
    digitalWrite(6, HIGH);
}
delay(10); // Delay a little bit to improve simulation performance
}

// -------------------------------------------------------