The "Hello World!" of Experimental Music Instruments
The first program every programmer learns consists in writing enough code to make their code show the sentence "Hello World!" on a screen.
Working with experimental music instruments, we propose the use of a VCO (voltage controlled oscillator) to program our Hello World!. This will allow us to hear our first tone and check if all is working fine.
You can use our official "VCO distorted"
board and solder each component. Also you can build the circuit using a breadboard. In both cases you will need the schematic:
Note: A circuit diagram (also known as an electrical diagram or electronic schematic) is a pictorial representation of an electrical circuit. It shows the different components of the circuit as simplified and standard pictograms, and the power and signal connections (buses) between the devices. Arrangement of the components and interconnections on the diagram does not usually correspond to their physical locations in the finished device.
The main component is a NE555 timer. When you use this timer in aestable mode you can get a digital waveform and we can control its frequency with a potentiometer. R5, R3 and C2 fix the NE555 timer to a range of frequencies. You can change this range connecting components with different values. The frequency can be calculated with the formula:
frequency = 1/(0.693 x C x (R5 + 2 x R3))
On the left of the diagram you can see the pin headers for the potentiometer that we are going to use to control the frequency. See how pin header no. 3 is connected to NE555 pin no 5 that is the voltage control pin.
On the right you can see more pin headers:
- The one on the top is for output. Pin 1 is connected to +5 volts, pin 2 is the output signal, pins 3 and 4 are connected to ground.
- The one that is below is for input. Pin 1 is connected to +5 volts, 2 is isolated, 3 and 4 are connected to ground.
Betweeen NE555 pin 3 and the output pinh headers you can see a button. When you push the button you are connecting NE555 pin 3 to the output pin header and you will hear a sound.
Photos:
"VCO Board"
"VCO Board mounted"
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