Post here about controller projects.
One thing I think I’ve discussed either here or elsewhere recently is my purchase of a 50cm “Softpot” or membrane potentiometer. There are designs for ribbon controllers online, in both MIDI and CV/Trigger/Gate form, and I’ll have fun playing with it. Has anybody here tried that?
They would be amazing if they “held” the last position that you touched rather than going null the moment you let go!
I can think of plenty of interesting things for these tho 
There are a number of different ways to treat the signal which would have the effect of holding the last note. I’d also suggest that a microcontroller can be very flexible there. You put out suitable triggers/gates, while holding the controller’s output DAC at the last level. Buttons on the controller strip can be used for sustain, soft, etc, to improve the controller’s musicality.
Throw in an attenuator knob and a modulation input and you’ve potentially got a pretty versatile instrument, without the need to tie up whole modules.
I’ve documented a couple instructables of controllers I’ve built for my modular and desktop synths at https://www.instructables.com/id/PacificCV-for-Modular-Synths/ (CV) and https://www.instructables.com/id/Oceania-Midi-Controller-for-Make-Noise-0-Coast-and/ (MIDI). I took advantage of the ATMEGA’s well-known built-in touch-sensitivity. Here’s a video of the CV version (turn down the volume-I forgot how horrible the lead I used was to listen to): https://www.youtube.com/watch?v=dE5faoOJr4k&feature=emb_logo
That also showcases a few of the other modules I’ve DIM’d.
Yeah, the way I got back into electronics was AVR (the same family of processors the ATMEGA line comes from, and the same family that features in Arduino boards.) I’m in the process of adapting a lovely Forth variant called Retro to AVR, but I have been hijacked by a resurgent fascination with analogue electronics. I’ve no idea whether anything will come of this, but the point is the journey. I’ve had a huge amount of fun with theremins, which are alarmingly easy to build. Wouldn’t it be fun to collaborate with a skilled thereminist on a synth project, exploring the potential of using sophisticated control instincts of the player to send control signals to the synthesizer. For instance a lot of people using a theremin for the first time instinctively adopt vibrato as a technique to seek the right note. But when the player is an expert this kind of playing (which involves a very delicate low frequency oscillation of the player’s right hand with respect to the pitch antenna) that nuance can be repurposed for control.
I’m probably not the first person to have this idea, so my ignorance of precedents is almost certainly due to the fact that I’m just riffing about something I haven’t researched enough. Sounds like fun, though.
Have you ever done the three-radio theremin? Sam has a video on it somewhere here…
I hadn’t heard of that approach to the Theremin. The design I use is Open Theremin, which piggybacks on an Arduino (so the sound is produced digitally, through wave tables which you can alter or even switch during play.)
Playing any theremin as a musical instrument is really difficult but it’s fun to use as a sound source and it has lots of potential as a hands-free controller.
I have been messing with making a DIY CV Joy stick
Based:https://sdiy.info/w/index.php?title=CGS_joystick_controller&mobileaction=toggle_view_desktop
Reddit Post:https://www.reddit.com/r/synthdiy/comments/fkh6vq/diy_cv_joystick/
It is working great Just need to finish it!
Thing of beauty! Do share your schematic when you can.
Thanks. It will basically be the same just with a TL074 In place of the TL072. But still might draw something up though.
Would appreciate it. I have a lovely joystick I want to use but am as yet unconvinced the schematics I’ve researched will work well which stops me from building as my build time is limited. You might also look at adding adjustable/switchable attenuation, inversion and amplification mods to your circuit to make it universally useful. (Or it might just ruin it so gaun yersel as we Scots say)
I have been looking at other joystick designs and see a CV input into some of them. Do you by any chance know what those would be doing?
I been prototyping the circuit added the range pot for the front panel and I am adding Leds so you can see the Negative voltage/postive voltage offset. Just need too add a buffer so it doesn’t drag the voltage output down.
By inversion do you mean the ability too the +V output to -V? it by a switch or something. Instead of using the offset to change the CV From +3V to -3V?
Joysticks are a nice way to control a synth. I have a Korg Wavestation EX which allows to mix 4 signal sources in a patch with a joystick. This makes for some nice evolving pads. And the movement can be recorded in midi so it can be replayed.
The CV inputs are generally like a control for the joystick, like vactrols on a pot allowing you to add in things like an lfo. Inversion, in short yes. Practically it’s having an output that outputs the inverse of the regular outputs.
I plan on having the offset and range on the panel so it adjustable. But I still trying too wrap my head around What -Voltage can be used for in Modular/CV. I have tried it and it doesn’t control pitch CV. Is it used for LFO CV or something similar?
I have the range pot a 50k that can go up too +8 volts fully maxed out. But I can only offset it too -3V.
I increased the offset pot too 100k and got a -V6.06.
I also added Blue/Red leds to indicate the amount of +V/-V its outputting with a buffer too not drag down the CV voltage and is working great.
I am looking into attenuation/amplification. But I don’t really see a use for a amplification circuit. When you can already adjust the range knob for up too +8 volts. Especially when its being used for CV on a 1 volt per octave oscillator.
So I think a passive attenuation might be the way too go.
A negative CV summed with a positive CV reduces that CV. So for instance on my Befaco Even VCO with the octave switch in the middle setting (which causes a CV of +5V internally to be added to the external CV), a negative external CV results in pitches below that octave.
Or an LFO that oscillates above and below 0V will vary the pitch above and below its starting point.
A joystick that puts out positive and negative CVs could be used to produce pitch bending both up and down.
Thanks that helps me understand the synthesizer related uses a little more. I just got too finalize a design and tweak the values and i’ll post the schematic.
Knob-O-Matic: it had to have a name of course …
I loved my Neutron and Model D from the start, but missed the possibility to change their settings the way I am used to doing with digital synths in a sequencer. So soon after buying them I build a midi2cv and a cv12 interface. Then of course I found I needed a controller to produce midi events which could be recorded by my sequencer and send to the midi2cv interfaces to control the analog gear. So I looked on the net and came across a midi controller made by Evan Kale ( most of his youtube videos are gone alas ). I got inspired by this and made my own version. It basically consists of an arduindo nano, 8 potentiometers, one rotary encoder a 2 x 20 LCD display, a midi-out connector (DIN style), a big square LED, a 4051 multiplexer and some code. So the Knob-O-Matic was born ( oh yes, pun intended ! ):
Oh yes, Zaphod B is the name I sometimes use when publising my music.
Its core is formed by an arduino nano that uses a CD4051 multiplexer to scan 8 potentiometers. Those are successively connected to the A0 input and their values are read.
.It will then translate the top 4 knob settings into midi note events for channels 1 … 4, and the bottom row knob settings to controller values (all on the same channel) and send them to the midi out port. The midi2cv interface can convert either note events or controller values to a CV voltage. The hex values are shown on the display.
While I was playing with the device and the Neutron I found that it I sometimes had to rotate a knob to the left to get some effect while my intuition would tell me to rotate the button to the right. So I added a menu system to the device controlled by a rotary encoder with push button which makes it possible to give the knobs a positive or negative ‘polarity’. So to either have an increasing value or ‘decreasing’ value (i.e. midi value = 127 - knob value) when turning the knob to the right.
The neat thing about making your own midi controller is exactly that. You use it for a while, come up with some idea about a new feature and just add it!
I printed the casing using pla on a prusa mk3 3d-printer.
The code, schematic and stl-files are available for anyone who wants to give this a go.
Do you know why Evan Kale removed the videos? I did his Bluetooth stereo mod as some starter projects and they are still working great. Kinda sad too see them removed.
No, I just found out today as I was searching for a reference.
