diy - DIY & Electronics

>>535
I'm not. But if you are, I would be totally interested in following your progress and soykaf.

Whacha doin', lainon? Do you have any specific ideas yet?

Well I only know how to play edrums, so I just want to make my own samples. And maybe play with leds like this dude.

Once I made an erhu using steel wires, a steel frame, and a part of a broken sax attached to the amplifier box. It sounded like METAL WEEPS OF DEMONS. I failed music that grade.

<- Here is the crappy contact microphone I made.

It is a piezo disk soldered to a 1/8" female jack socket.

A contact mic only picks up the vibrations travelling through solid objects, not the vibrations in the air. Connect the jack to a battery powered amp and speaker or even directly to an active PC speaker. Blu-Tack it to a surface and play around with it.

Total cost was around £3, so there is no excuse not to try this project. You can build this even if you don't have the tools to do soldering but the connections won't be as strong, you just need two bits of wire, a piezo disk and the jack, strip the wire and twist it to connect it up.

My next planned project is a set of Schmitt-trigger oscillators. Just need the chip, couple of capacitors and resistors, 9V battery, potentiometer and breadboard. I will keep you posted on progress.

I'm currently trying to program a bassline synthesizer for electronic music production. My idea is to generate data in the Fourier space and then take the reverse transform of it in order to get an audio sample.

I'm also thinking of implementing user defined envelopes (functions that control the volume or other parameter of the sample as a function of time), perhaps something hand drawn for maximum freedom.

>>543
any recordings?
I wanna hear it in action

>>545
tilde.city/~sasha/201503171946.flac - xbox controller motor sounds
tilde.city/~sasha/201503172028.flac - re-recording of subwoofer playing out some Richard Chartier

There is clipping. I am not sorry about it.

>>546
nice, thanks
The sound is much more clear than I expected it to be, although I would have used the piezo from computer motherboard and would use lower resistance wires, this is really good project for some cheap buck, thanks once again

Work in progress:

http://tilde.city/~sasha/derp.mp3

audio ripped from an episode of Lain + some crap beats I stole off the internet, all cut up and warped in audacity

Today I built an oscillator.

It sounds like this http://tilde.city/~sasha/oscillator.mp4

Soon I will build more oscillators and feed them into each other (I can put 6 on this chip)

Let me know if you're interested and I'll write it up for the zine.

>>584
Please do!
Myself and many others would love to read through it and recreate the steps

>>535
I'm building a synthesizer that uses direct digital synthesis (inverse FFT) for the waveforms with digitally controlled analog filters.

Progress http://tilde.city/~sasha/oscillator2.mp4

>>584
What IC is that?

>>593
not that anon, but you can do the same thing with 555

>>593
It's a 40106 Hex Inverting Schmitt Trigger. 6 logical NOT gates on a chip.

Pin 7 and 14 are power.

We take the output from one NOT gate pin 2 and feed it to its own input pin 1 through a resistor, with a capacitor between pin 1 and ground. The NOT gate flips about and we get a square wave.

>>594
That's what I thought. I was wondering why what he used had so many pins.

>>595
Neat. The capacitor makes the wave uniform?

>>598
There are three things at play:

1. This is a logic chip, so pin 2 is either 'on' or 'off', with on always being the same voltage. So we either get high voltage or nothing sent to the audio output. This gives the output a square waveform.

2. The "Schmitt Trigger": The threshold to trigger the gate to flip to 'on' (a low voltage at pin 1) and the threshold to flip back to off (a high voltage at pin 2) are different on this chip. So when pin 2 is 'off' the voltage supplied to pin 1 has to decay quite a bit before pin 2 will switch 'on' again. Once it's on the voltage has to ramp up quite a bit to switch pin 2 'off'. So the output has two relatively stable states and oscillates between the two.

3. The capacitor takes a little time to fill up with charge received via the resistor from pin 2 before it discharges. If you liked you could work out the exact time with some equation using the resistor and capacitor values. Since I'm using a potentiometer (variable resistor with a knob) I can change the frequency of the oscillations.

>>594
555 is also a good chip for an oscillator. You set up a couple of capacitors and resistors to control the timing in a similar way and you get a high-low oscillation output at pin 3.

>>590
I really want to build a few of the things from that site. My dream is to build a 'noise box' of my own design with a few oscillators and a some tone and distortion controls. Gotta get my 'minimum viable product' complete first though.

The Hackaday "Logic Noise" articles about abusing TTL logic chips for synth use are also good.
They have moved on from the basic 4069 osc and are now making amplifiers and filters from it!

If you guy are looking for a cool easy project, you could always build a 3 radio theremin.

https://www.youtube.com/watch?v=PSYPUhPGavQ

But I must warn you that this machine is a untameable noisy ambient texture generator. Made one for a girl once… She liked it.

>>544
I had an idea for a similar synth.
basically you distribute diracs and such in the frequency spectrum, and with some functions or such you control their behavior/parameters.
A reverse transform would generate a signal.
For example you could create a sine, and manipulate its frequency and amplitude in the form of some function.
Or distribute diracs in such a fashion that they create a square-wave, and manipulate some of its harmonics.
I imagine you could do some cool soykaf with that, and if its well done have some nice visualization of what is going on.