Arduino Forum

Using Arduino => Audio => Topic started by: druffns on Apr 19, 2019, 02:34 pm

Title: DAW Controller - old mixing console
Post by: druffns on Apr 19, 2019, 02:34 pm
Hi guys

first of all i want to say i am an absolute newbie in everything i have done in this project so there are for sure more efficient ways to do the stuff i made and probably there is some stuff that i totally made wrong :D. Code is a mess and there are a few problems but it works! Maybe there are people out there who want to do something similar, so i want to share the project.

i have used

1 x Arduino Nano
3 x CD74HC4067 Multiplexer
parts of the Old Mixing Console
a lot of cable and some LED

So i have made an „daw controller" out of an old defect analog mixer. At the momentan i have working 16 Faders, 16 Potis and 10 Pushbuttons. With these i can control the faders of DAW´s  and other stuff like play stop cut and with the potis i control Plug ins (tested on Studio One 4 and Reaper)… All over Midi.

The Faders are connected to the mux (and of course 5v and gnd) and the analogread is mapped to 0 - 127. Every Fader has its own number and at the beginning i was sending all midi over Channel 1. I then had the idea that maybe there is need for  more than 16 fadercontrollable Tracks. I then took a Pushbutton to Change a value of an int and when the value changed the 16 fader send the value over an higher midi channel and trigger the led so i can see where i am (0-16 or 17-32) .Now i have "32" working

The same, except for the change channel, goes for the rotary Potis

The buttons are connected to a Muxer and send the value 1 when pressed

The problems i encountered were that i had bought arduino nano which means no midi over usb, which isnt a big problem but you have to use some midi bridge like Hairless midiserial and loopMidi to get your Signal from the Arduino to a DAW
Another problem is, that the old mixing console has logarithmic audio faders and potis in it and for the arduino daw stuff you need linear. I came across a few workarounds which neither worked fine for me. Another Problem was that the potis i unsoldered have been very differently. Some „counted" up when turned right, some down

The „biggest problem" is that the potis and faders are logarithmic, maybe i will buy some linear stuff in the future but for now it works really well when you know how to handle it

Englisch is not my first language so the code is a mix between englisch and german, sorry for that

maybe this helps some people or someone is inspired

here is a short demonstration: youtube (

Title: Re: DAW Controller - old mixing console
Post by: MarkT on Apr 19, 2019, 11:08 pm
Interesting conversion - you'll find a lot of pots are log or reverse log in a console, although the main
faders tend to have modified laws for finer control than a standard log taper (ie more linear at the top).

There might be ways using diodes to do a rough log to linear conversion - the current through the pot
is fed to ground through a diode (suitably limited), and the voltage across the diode will be fairly linear
in the 0.5 to 0.7V range - might be possible to feed that back through the analog multiplexer so a single
linearizing circuit can be switched between pots in turn.
Title: Re: DAW Controller - old mixing console
Post by: druffns on Apr 20, 2019, 11:58 am
ah okay thanks. I never came across diodes when searching about the linear logarithmic topic.
I will do a bit research maybe this will do it. The way over diodes would be much cheaper than buying new faders or new pots i think.

Thanks for that MarkT !

Title: Re: DAW Controller - old mixing console
Post by: MarkT on Apr 21, 2019, 03:46 pm
There is an issue with the small voltages involved - you can however stack several diodes in series to
multiply this up.  3 1N4148's in series will give 1.5 to 2.5V range perhaps?

And the forward voltages change with temperature - this can be compensated for with a fixed
diode string in the same environment (so same temp).