Boxing up the Loneoceans' midi2 controller

[Mads Barnkob]

Long ago I bought one of Gao/Loneoceans' midi2 controllers: http://loneoceans.com/labs/sales/midi2/

I finally dug it out from the pile of kits-to-build-when-I-get-time(tm) and found a suitable aluminium box to house it in.

It has two outputs for optical transmitters, so I wanted to put one of each kind in for each channel, so it will have both a blue IF plastic fiber transmitter (IF-E97) as well as the ST Fiber transmitters (OPF1414T). I will make a separate PCB for these 4 to be mounted in the side of the box.

For the front I wanted to make a simple etched PCB for text, markings etc. It was easy and fast to make in ExpressPCB.

So far I got to etch the front and prepare all the potentiometers and switches with wires

[Mads Barnkob]

All potentiometers, switches and push buttons have been mounted in the lid with front plate on. I had the front plate mounted on the lid with the 6 screws when I did all the holes through both front plate and lid at the same time, to ensure perfect alignment, but I fooled myself. As the lid was not mounted on the box, the 6 lid screws was not in center and I will properly break a few of the corners when mounting the lid, since the screws come in off center

If anyone else ever build one of these, be sure to notice that the connection points for PW, Frequency and SW are mirrored (channel 1/2), but the optical output connections are not mirrored, so it is easy to mix up the turn direction of the potentiometers and that midi/fixed switch works opposite.

Next job to be done is making a small PCB for the 4 optical transmitters, a small front plate and drill the holes for those and the MIDI connector in the case.

[futurist]

Looks quite nice so far! Are you planning to coat PCB to prevent copper oxidation?

I'm also thinking about purchasing his controller, looking forward to see live test

[oneKone]

That's turning out mint! The front plate looks clean as. I'm looking forward to see the end result

[Mads Barnkob]

I thought about coating it, but the clean copper is just too shiny, so you have to see it at the right angle against the light to read the text, so I will left it oxidise and brown up by itself, I tried baking soda so speed the process, but that did not really give anything, most likely because the baking powder that I had was != baking soda 

I finished up the optical board and plate for that, unfortunately the box was too thick-walled for the two ST Fiber transmitters to hold the plate in place, so it need some bigger holes and two screws.

Then I searched the house for a 9V battery, found none and went to bed. Ill find a 9V battery and will either rig up a small DRSSTC or make a simulator, properly the latter since being very noisy with a DRSSTC after daughter is put to bed is a no-go.

[Mads Barnkob]

I checked out the fixed mode with my oscilloscope and it was dead on 10 - 360 uS on-time for the maximum setting on the SMD potentiometer and also the freqeuncy from 100 to 300 Hz was perfect, nothing to point fingers at there.

I played 4 MIDI tracks and its a little varying on how much on-time is needed to play all the notes, I played mostly 2-4 notes at a time here and I think the on-time was around 100 uS for a 300 kHz coil. The primary coil, IGBT heat sink and secondary coil was warm to the touch after a 1 minute play time

Recorded with a 5Dmk3 and a H2n zoom external microphone, no sound clipping!

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