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studio ponnuki is a small creative studio hidden in the beautiful mountains of the kootenays

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geoffroy

Designer / Hacker / Maker

Loves green tea, meditation and noise

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melina

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naima

Drawing / Dirt Pudding / Maker

Loves green tea, meditation and noise

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May 17, 2010

3rd post mixer DYI ~ doepfer usb64

I am getting really close to a working mixer! The hardware is ready I simply need to build a project box in order to host the project.

As you know from previous posts, I built a prototype of the mixer with and Arduino Board ~ connecting to processing, hosted on a puredyne machine. This was all working fine and would have been good enough for my needs, but arduino send serial signlas over USB which isn’t understood by audio software. A driver needs to be built or a ‘host’ software needs to decode the serial and transmit midi. I could have used pureData or processing to be that host, but in the end it would only slow down the signals. So I needed to find a way to create midi usb device.

I found out that Doepfer (a German company that build Analogue Moduar synth (like the Dark energy that you can hear in few of my tracks) also sells DIY kits. One of their kit is called USB64 and it is a USB Midi controller card. In short you can build your own usb and/or midi controller with this card. But be warned it’s not for the beginner ~ it’s not an arduino type of DIY, you need some good thinking and some soldering skills.

The USB64 has,of course, 64 midi signals connections. These 64 connections are mapped on the bottom of the card in cluster of 10 pins, 2 of which are the 5volts and the ground. My first learning experience was to realized that all the singnals pins need to be connected to the ground or the 5 volts when not in use. So there was no shortcut to try out the card, I had to ground all these connection. With my really limited electronic knowledge I try to bundle wires all around the 10 connections with only massive failure. There was nothing to do ~ I would connect the card to the computer and there would be a constant stream of midi signals being sent to my computer – I had to resolve to soldering!

Ok I have’t solder in the last 20 years of my life – I am 31 – so last time was when I was 11. You can deduct from that my skill level. Luckily I had some spare boards around, one of them had some sort of bread board layout which helped a lot in the soldering of the board. I had to split the 8 cluster of 10 connection into 64 line of 3 connection (signal, 5v, ground). With a bit of thinkering and a load of led I ended up creating something that worked. I I knew how to draw schematic I would do it right now – but it’s also part of the fun of figuring out how to do it 😉 If you need more info I can send you better picture of what I did.

So long story short – I had to create a boar in between my doepfer USB64 and the sliders and hub – I also had to sue jumper to ground all the unused connection and when all that was in place I could connect to Mixxx. To my great surprise, Mixxx detected the card properly and I could simply run the midi detection wizard to assign all the knobs and fader to the software interface!

You can see it all in action in this video (filmed with my new camera ~ enjoy the better sound and video quality!). My next step being to create a project box – or the body of the mixer to be able to carry around – which will be another great experience in the world of the unknown of building my own usb audio mixer ! Stay tuned !