Schematic is avaiable HERE.

Despite the lingering reality that most of us don't have what it takes to make it to the upper reaches of the Hit Parade, there remain many who still harbour a secret desire to make music. What better...

this is a project based largely on the put up or shut up mentality, for quite some time I've been getting annoyed at seeing youtube videos of people pissing about with these "synths" which are basically boxes of 555 timers with a million knobs that make stupid noises that you couldn't ever actually use in music so I thought I would make my own little synth that would get repeatable sounds and be useful in music and what better type of synth? a droner type - basically cause I love bagpipes - I like drones anyway the circuit itself is quite a simple one basically because I only designed it during the week, all it is really is 3 triangle wave generators configured to operate in the audio range going into a mixer op-amp configuration with the odd filter here and there to soften the waveforms I've used LM358 op-amps cause they are the cheapest, I'm not too sure if others would work in the same way though they probably will. why call it the devils triangle - well it has 3 oscillators one of which can oscillate a slightly high pitch range (for melody) it also sounds demonic so the name fit Hope you enjoy EDIT: I replaced the level knobs with on/off switches - it makes it so much more versatile being able to silent certain drones EDIT: I added a little schematic on how the switches should be wired as it was causing a bit of confusion. the one I made - with a really shit paint job

DIY Arduino String Synth With Analogue Filter ***Updates at bottom of page - Easy to read Schematics etc**** Just like the Arduino Drum Machine, this is another build based on the amazing work of Jan Ostman, who is generous enough to share the code over on his website; ***Old website*** https://janostman.wordpress.com/how-to-build-your-very-own-string-synth/ ***New Website*** http://synthworks.eu/arduino-string-synthesizer/ The suggested $3 dollar donation is quite simply amazing value for money, so if you use this, don't forget to tip! On top of Jan's work, I've added a 12db filter with resonance (based on this design) to add a bit more sound sculpting to the synth. Filters are a massive part of synthesis to me (mainly because I can't play but can quite happily turn knob) and an analogue filter really adds to the warmth 'wobble' of the synth. The filter has a separate on/off switch and bypass switch. Looking back it would've been better to build that into one switch, and also to move the output further to the right. Ahhh the power of hindsight. I wanted the synth to look very Minimoog-ish or Prophet 5-ish, which I think I achieved, but building the case was by far and away the hardest part of the build (due to my own inexperience/stupidity). Total build time was spread over 3 months and probably took about 20 hours (most of that time was spent staring at nothing trying to think what to do next). If I were to make it again I think I could get it down to about ten hours, if luck was on my side. Here's a quick video of it in action; Parts The total cost of parts came to about €60, with most of that going on the MIDITECH midi keyboard. I used a cheap Chinese Arduino Nano clone to keep the cost down (around €2), then a few pots and resistors etc again from China. Also high quality plywood from Modulor for €2.90 (I think it was 6.5cmx250x500). The perspex was also from Modulor. Obviously if you don't already own wood stain and glue etc your cost will be significantly higher. For the panels I used my banggood laser engraver, which I think adds massively to the look of the synth. If you don't have one of these you could use a label printer. Electronics Jan's website documents the build process pretty well, so go check there for schematics etc. I did manage to draw up the wiring diagram which may save somebody a bit of time when hooking up the keys (find it somewhere below). I started by taking apart the MIDITECH and unplugging the ribbon cables; You won't need this part any longer so remove it to save some space; I soldered the Arduino Nano to some perfboard to make it easier to handle (and to screw down to the chassis later on). Then using some ribbon cables I began to figure out how to connect the keyboards out's with the Arduino's In's. Eventually I figured out what went where and soldered it all down and covered the connectors with heat-shrink. You'll probably save a bit of time if you use this; That's the majority of the synth finished! From the nano's output I added a bypass switch and then the 12db filter. I forgot to take any pictures of that though until it was already attached - sorry! But it all fitted onto another small perf-board; The Case I started by cutting some cheap board and securing the key-bed onto it. This gave me an idea of the final size of the synth to which I based my design around. I kept the bottom plastic of the MIDITECH (always capitals!) keyboard because it would secure down easier (using it's screw holes) and also because it would probably be a pain to try and re-construct it any other way. I also added some 'feet' at this point. Feet... With bottom panel size known, I sketched out the rest of the case... The side panels; All the parts have been cut here (the other bit of perspex with the dials on was temporary just to make sure it was still working); Notice the pencil with my name written on it. That's mine it is. Then using my old friend Ponal Wood glue I started sticking everything together (including fingers, clothes and everything else); Then it was time to design the front panel and the laser engrave it onto perspex. The smell was awful (and toxic)... I stayed in the room long enough to feel faint. I did sleep well that night though. Running a test on card; Burn! After it was engraved I filled it in with white acrylic paint; With the panels and case completed it was time to stain the wood. I used a mahogany brown stain, using two or three coats. The trick here is not to use to0 much and to keep it moving when it's been applied, otherwise you'll get an uneven finish. Once this had dried it was time to add the varnish. Like with the stain, I find it's best to use only a tiny amount and spread it out as much as possible to get the best finish (you can always add another layer later). With this synth I found one layer to be enough; Once this has dried you can now put it all together. For extra security I also used some hot glue to do this (and it's not fallen apart yet) I added screws to secure the perspex panel but can't find a picture of that. But I'm sure you can imagine what it looks like. Conclusion Overall I'm pretty happy with how it turned out, with only a few gaps in the wood caused by my rubbish cutting/maths skills. Should I make it again I'd move the output over to the far-right as I've noticed it's possible to knock the cable when going mad on the filter (you should only touch a synthesisers knobs as if they are really hot, otherwise you're not a real synthesist). I've been learning C for a while, but it's a massive mountain to climb. From here though I've bought the following book; When I eventually get around to reading it, it should give me a better idea of what's going on in the code, then I'd like to attempt a version 2 using maybe an Arduino Due and add some more controls. Thanks! ****UPDATE**** SIMPLIFIED SCHEMATICS Below is a simplified schematic for the string synth... Sorry it's not the best quality I'll try and take a better picture later, but hopefully this should be of help those of you new to schematics that want to try and build this synth. The connections where it says 'goes to keyboard', you can see elsewhere in this blog for another detailed diagram of where and how these can be wired up to the keys. As for the potentiometers, I *think* I've drawn them the correct way (if you make this and the pots are working the opposite as you'd expect, swap around the ground and 5v connections on each pot). If the drawing is incorrect, let me know and I'll re-do it. Even if this version is wrong, nothing will break & it'll still work OK (just the pots will work in reverse). You can see where the pots 5volt and ground connections need to go in the diagram, I didn't join them in the picture because the wires would start overlapping and become confusing. It's pretty obvious what to do though. Also drawn is the audio out headphone socket, with the positive voltage/audio signal coming from the output D11, which then goes through the resister/capacitor (which acts as a filter to reduce some of the noise from the Arduino). The other side of the audio goes to the ground signal. If you don't know how to wire up a audio jack, maybe google 'audio jack pin-out' or 'audio socket wiring diagram'. If you plan on adding the analogue filter, you'd leave off the audio jack and have the previously mention positive wire go into the input of the filter. You'll have to learn to read the schematic for that I'm afraid, as I couldn't really simplify it without it becoming more complicated than a normal schematic. Give me a shout if you get stuck though. Good luck! P.S I'll draw a simplified schematic for the Arduino drum machine soon. ****UPDATE PART 2****** Below is a wiring diagram to add a bypass switch to the filter; ...And if you were struggling to figure out how to wire up the Pots for the filter, I've drawn out a simple picture showing how (I've had to do this whilst away traveling, so it's partly drawn from memory but I'm pretty certain it's correct)... Obviously the drawing only shows how the pots are wired and not the full schematic. Go look at the proper schematic for the rest of the plans, but this will give you a good idea of how to wire up the pots. Powering the filter from a 9v Battery will give it it a bit more 'oomph', so if you'd like to do that, the below illustration will give you an idea. Further, should you want an LED indicator showing if the filter is switched on or not, see the chequered box; I only had SPDT switches available when I built the synth, so that's why there's separate switches for both the on/off & bypass, but you could easily just use one 2PDT to save space. You could even add an audio in jack at the start of the filter to process other audio. Good luck! ***UPDATE Arduino Drum Machine**** Simplified Schematic Ok, so this 'simplified' schematic might not actually make things any simpler! But some people have asked for it, so maybe it'll help clear somethings up a little bit - especially how to wire up the audio output and pots/switches. This was drawn from memory so I hope it's correct - give me a shout if not and I'll update (the pots might work in reverse, but they'll still work). I'd also urge you to look at the schematic on Jan Ostman's website for more help; https://janostman.wordpress.com/the-o2-source-code/ Thanks!

Make your own clock module for your modular synthesizer!

Moog Light Synth V2: This synth is a pulse width modulated oscillator, routed through a light-controlled resonant low pass filter. The "growling" oscillator tonality is supplied via a PWM and an awesome high-resonance low pass filter. The oscillator is controlled via 2…

Electronics Projects For Hobbyists Makers And Hackers With Stripboard Layouts

Make your own clock module for your modular synthesizer!

This is a super simple and easily customizable little synthesizer. This is my first time using the Arduino and also with acrylic, both I found very fun to work with though. This is also my first Instructables so hopefully I have explained this well enough. Step 1: Part and tools For the innards: Arduino Uno

More Circuit, PCB layout! This just shares PCB Power Amplifier, Tone Control Speaker Protector, etc. You can see all about PCB Desig...

This was kind of a rush thing I did today because I have a few projects awaiting various IC's which I can't publish yet but I haven't posted anything this week so I thought I would lash up a LED Ring Oscillator - I'm sure you've seen these things on the net in various guises, mine has increasing value resistors which basically makes the oscillator more predictable in the way it rotates and which LED starts first which was quite important for this as it's going to be part of a LED/LDR circuit you'll notice that the schematic I've done isn't in my usual notebook format but instead I used a program from the CD off the front of a magazine called circuit wizard - it's okay for testing little circuits like this so I thought I would just upload the schematic I drew in that anyway as usual the stripboard has been built up and it works - the rate is voltage controlled so the less voltage you feed into it the slowed the LEDs will light up - my favorite voltage is about 3.3v which is cool for uController projects that already have that voltage available - I've tested mine upto 16 volts but I couldn't go any further due to the capacitors I was using.

Gristleizer famous audio effects unit Throbbing Gristle DIY stripboard layout and explanation build your own.

Un SUB oscillator avec -1 ou -2 octave. Pot select octave Led indicatrice Jack in Jack out L’arrière Schéma et stripboard : Source : Carmelo Azzarello Merci aussi à Jos Bouten pour l’aj…

Double Delay Effect: SUPER simple double delay effect! My goal was to build the most compact, zaniest delay possible using only a handful of components. The result is an enclosure-less, easily-modifieable noise machine with a suprisingly massive sound. UPDATE: Details…

Frequency Divider Circuit using 555 Timer and CD4017

Hack the original 1978 arcade audio chip for classic and novel sound FX

I've been doing some DSP on the Arduino Since signal processing is so computationally intensive, we tend to associate it with powerful processors, like the mighty ARM of the DUE. However, it is entirely possible to do useful signal processing tasks - such as running digital filters, or even performing Fourier Transforms - on humble little processors like the ATmega328 on the Arduino. These past few days I've been doing just that. The application is within music - specifically, on my new modular synthesizer. But don't look away just because you might not be interested in music, for underlying this is an entirely general application of real-time programming. My synthesizer already had (as you might have seen) a couple of envelope generators, capable of producing exponential 'attack' and 'release' envelopes at the edges (or at the beginning) of a gate pulse. However, I wanted a more traditional 'ADSR' envelope generator with the capability to generate independent control of three time constants: attach, release and 'decay', as well as to manage the amplitude of a 'sustain' phase. This type of circuit needs two core elements: a first-order circuit with three controllable time constants logic to switch between the three exponential decay phases and manage the 'sustain' phase. Ordinary ADSR circuits charge or discharge a capacitor at three different rates; an analog solution involving a simple, first-order differential equation (albeit with changing coefficients). The exponential voltage required in any phase is the voltage on the capacitor of a trivial RC filter. It struck me that - given the requirement for the logic around the analog filter, the entire system might be better implemented by a micro-controller, replacing the analog 'filter' with its digital equivalent. I certainly don't claim any novelty in this thought - indeed, it was reading about Tom Wiltshire's excellent Digital Envelope Generator which motivated me to give it a try. But the experiences of doing some more work back in PIC-land last week (more of that in a later post) reminded my just how dry and tedious that place can be, so I set about trying it on the homely little Arduino. Neither do I claim any novelty about the idea of doing it on an Arduino - somebody/several bodies must have done it on this platform before (indeed, I got a first version running using ADSR() from Mozzi, but I didn't like that for several reasons, most important of which was management of the sustain phase). Anyway, whatever the reasons, I wanted to have a bash for myself. Let's take a look at my code first. Here's the core first-order difference equation which - in any of the phases of operation - produces the required exponential envelope... 'envelope' is the main variable, which is updated every pass through the program to its next value, ready to be output to the DAC in the 'Set_DAC_4921()' subroutine. 'alpha' is actually the location of the single pole of the digital filter (remember - this is a first order digital filter) and it determines the 'time constant' of the exponential decay. 'drive' is a constant, driving the step response of the filter in this phase. The factor (1-alpha) is required to correct the overall gain of the filter to unity at zero frequency. If you don't understand the math behind this stuff don't worry - you can read about it in a book if you like - or you can just be content to use the results. I've written the difference equation in the comment above in something close to 'conventional' notation, for those who do understand these things. That was the first of the two 'core elements' - the digital filter implementing the exponential response. The second part is the logic. Here's a snapshot of part of that logic... To be precise, it is the part of the logic which tests if the envelope is at the end of the attack phase. If it is the end, new values of 'drive' and 'alpha', relevant for the next phase - the decay phase - are loaded. Enough dry talk of the inside of the code - if you want to see it all, you can download it from this github repository. I had to give it a name and I followed the rather childish practice of choosing names which pick up on the involvement of the Arduino: 'ADSRduino'. Sorry. Instead of talking, let's see some action. You probably weren't impressed with the rather quantized image at the top of the post. What you didn't know was that entire envelope was less than 10ms long (shown in order to demonstrate that this system is appropriately fast - in fact, the sample rate [that's to say, the rate at which the difference equation is operated] is around 3.3kHz). Here's a longer event (around 400ms long) along with the gate pulse from my keyboard which triggered it. It leaves time for envelope to move through the quantization steps of the DAC more slowly, making for a smoother trace. Here's the same thing, annotated to make it clear what all this is about: You can see that the attack phase starts when the note is gated and rises up to full value (actually 5V) then falls down in the decay phase to the sustain level. The note is sustained until the gate is released (unless it already has been released), after which the release phase begins. The time constants for attack, decay and release - and the level for sustain, are adjustable via user potentiometers. To illustrate the point, here's another setting (with fast attack and lower sustain and, as it happens, I pressed down the key for longer, so the gate pulse and associated sustain phase is longer): All of this is actually running on useful hardware. It started as a prototype on an Arduino UNO and then migrated onto a physically smaller NANO, which is seen here... You can see both the original trimpots used for the ADSR controls and the new potentiometers on a front panel (made from double-sided copper-clad board, painted black to make it look fancy) - as well as sockets for the gate input and the output. There's also a switch to select a looping mode, in which the system can automatically re-trigger itself. You can also just see (at the right-hand end of the breadboard) the little MCP4921 12-bit DAC used to output the envelope voltage. The circuitry above was moved onto a piece of stripboard: and assembled, using the bracket bent up from sheet steel, into a complete 'Eurorack' module: You can find a schematic for the whole system here It now does great service in the considerably extended modular synthesizer: where it sits next to another Arduino-based module, running as a voltage-controlled digital wavetable oscillator, built upon resources from the Mozzi library. Of course, as I mentioned at the top of this post, you can take the signal processing ideas on the Arduino further than first-order. I've been playing with a biquad structure on the Arduino within the loop() function... (in which all the elements have their usual meaning). I found that it is easy to achieve a sample rate of 2 kHz which - although it isn't useful for audio frequency work - does make for some very useful filtering for signal detection etc. If you need to detect or monitor AF signals, the Fast Fourier and Hartley Transforms work very well at sample rates of tens of kHz - but that's a rather different kettle of fish. Don't overlook the little ATmega328 when you're playing with a time-varying signal that takes you to the edge of a DSP application. You can run some genuine digital filtering algorithms (including floating point math to manage poles right up close to the unit circle) and have fun in the process. ...-.- de m0xpd

Build a multifunction sound synthesizer using a surprisingly fun audio chip.

He aqui elf iltro mas facil que he podido escontrar.esta extraido de el dise ño de el WSG de Ray wilson y suena realmente caustico.

SubaQuatic Bass Machine Oscilador triple de frecuencias bajas de onda sinusoide circuito original de Constanza Piña y Daniel Llermaly 2010 SubaQuatic Bass Machine es un dispositivo generador de son…

A multi channel audio mixer circuit based on LM3900 quad opamap IC. The audio mixer circuit has four channels, two mic and two line inputs

After SITS oscillator, let’s try making combining some oscillators into one sound output. There’s many ways for us to build a lo-fi instruments from cheap electronics part that we can e…

Korg Mini-Pops DIY Drum Machine This is a really cool build; It a recreation of the Korg Mini-Pops drum machine, an instrument which has been on a ton of records the most famous of which might be Jean Michelle Jarre’s ‘Oxegen’ album, hence this clone being called the ’O2’. The brilliant Jan Ostman built this using only an Arduino nano and a few barebone parts. Jan is giving away the full details on his website and is only asking for a $3 donation in return. Bargain! https://janostman.wordpress.com/the-o2-source-code/ ***Update*** If the linked website is no longer working, use the Internet Archive to visit a cached version of the site (copy and paste the address and choose a date from around when this pages was posted: around Dec 2016). ***MIDI update*** From the forums of Look Mum No Computer, somebody has posted the code but with the MIDI update; https://www.mediafire.com/file/5hwyuvykzn8kszg/O2minipops2midiout.ino/file (Read the forum for more info and schematic). ***More Advanced Model Update*** If you'd like to build a more advanced version, head over to the NoiseyMaker website for more info and a nice detailed guide. This version builds on the original & adds some advanced features like a display and even pitch control of the samples. Also the drum patterns have been updated to be a bit more 4/4 time 'electronic-style', rather than than some of the 3/4 time waltz in the original code (you could always copy & paste these over to the old code if you wished). .... I started by building my first version using a cheap Maplin plastic enclosure, but I thought it was worth spending a little more time on it so I got the table saw out. Because the table saw has a maximum cutting width of 7cm, I based the case around this limitation. The switches mute the individual drum hits. The pots select the pattern and its tempo. V3. ***UPDATE Arduino Drum Machine**** Simplified Schematic Ok, so this 'simplified' schematic might not actually make things any simpler! But some people have asked for it, so maybe it'll help clear somethings up a little bit - especially how to wire up the audio output and pots/switches. This was drawn from memory so I hope it's correct - give me a shout if not and I'll update (the pots might work in reverse, but they'll still work). I'd also urge you to look at the schematic on Jan Ostman's website for more help; https://janostman.wordpress.com/the-o2-source-code/ Thanks!

A very special synthesized drum voice inspire by very rare Vox Percussion King B829 from around 1967. A long description of the build, schematic and demo! Original device was used by Grandmaster Flash and Kraftwerk.

As a companion to my simple op-amp AR envelope circuit, here’s a discrete version. It has the same basic functionality – gated input, variable attack and release times – but is made with transistor…

This electronic organ circuit is very simple to construct and is basically an emitter-coupled oscillator composed of T2 and T3. An squarewave voltage can

Wouldn't it be cool, to be able to mix in different sub-octaves of a frequency, similar to an organ or my old Korg poly800, without using up...