DIY USB host - MIDI DIN converter - USBpal released


+1 for a DIN midi input option if possible: the problem with the USB-midi converters available at the moment is that they have to go first in your chain. If there’s a way to merge the DIN input with the USB and send it to the DIN output then you’ll be onto a total winner. I’m aware not everyone needs this though- great project either way!



Feature creep is where something starts out with a set of goals and functionality but customers demand extra things it can turn into a very messy hard to use product as a result. It’s more a problem for the traditional waterfall project lifecycle.



I see. :slight_smile: Then I remind the primary idea of a target situation:



I’d definitely be interested in a ready built unit.



Looks great for those of us with din midi! :slight_smile:

However, I am reminded of all the beginners who believe they could use usb hubs to route usb midi. Having a copy of the din out on a usb out may attract more beginners, especially if that usb out is powered.

So when will you start manufacturing your own line of modules? :wink:



This is so needed. There’s so many nice little controllers and keyboards that are USB only and lots of nice MIDI controlled tiny synths. Would be great if it could be battery powered, or even powered off the 5v from the MIDI. Openmusiclabs had a midi powered synth once (Vampire?)



@t2k: changed to mini USB

MIDI IN: a solder point (3V3 - Rx - GND) will be provided

@audiohoarder: what situation do you think of if you consider din out on powered usb out?

@mongrol: it could be powered by a simple USB power bank, the gadget itself draws not much current, you only need power to supply the controllers/keyboards. MIDI-powered is not possible.

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I’m just struggling a bit with SYSEX messages. How can they be merged properly? SYSEX can be quite big.

Can anybody share his experience?



@Picard: Here are two instances that come to mind.

1: Someone needs to connect two USB only devices to each other. One is a midi keyboard, the other is some synthesizer with midi over USB only. Unfortunately, the market is tending in this direction, so this is very common among beginners with no DIN midi devices.

2:The same as the above, but the power for the device has to come over USB as well. This means that the only way to use the device properly is to hook it to a computer. This is where a powered USB midi port can save the day. This would be neat for Arduino users too.

USB power sounds great. Never underestimate how useful a USB battery pack is!

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Great that you’ll include a midi in!
I wonder since the the usb host input on the controller is min usb.
For connecting my KORG nanokeys or nanokontrol i’ll need a miniusb to miniusb cable. I’ve actually never seen such a cable. Wouldn’t it be more logical if it has a normal usb port you’ll find o most computers? And everybody already has those cables.



> I’m just struggling a bit with SYSEX messages. How can they be merged properly? SYSEX can be quite big. Can anybody share his experience?

You’ll have to block the other input during the SysEx message. You also want to think about how to handle MIDI clock. Kenton has some decent merging rules described in their manuals that might be of interest to you. See

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@shiftr The Mini USB port will be for power only. The USB host port will be a regular USB socket. There’s no such thing as a mini-to-mini cable; USB host ports are all supposed to be of the “big rectangular” kind. Well, until USB-C came along, that is…



Ah ok… that was a mis understanding i took from the picture then.
Aso what i love about the design is that it has all connections on one side. I actually already have the kenton usb host but because it has cables on front and backside it’s always a mess to use in a setup.



I’d be interested in a built one too



@audiohoarder: I see. Do you have some examples for usb-synths in mind? So this would need two powered usb hosts - one receiving and the other one transmitting midi messages, right? Let me think about it… And what would the Arduino people do with this?

@shiftr: as t2k said, the mini is 5V DC in only.
The design origin of the connectors on one side was to have only one panel for drilling&milling…

@t2k: thanks!



Another thing to have in mind: it would be great if you could add another pair of holes on the pcb to fix inside enclosures, having only two holes would make it somewhat flimsy particularly with the din midi sockets which exert quite some torque on the board.
At the very least consider a third hole which would be better than just two.
Just my two cents!

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Second that. Plugging MIDI in and out puts quite some strain o the PCB, it needs at least 3 (but 4 would be better) holes to be firmly mounted and not put too much strain on those 2 fastening holes.



@Picard: The Roland Boutique range can only be powered via AA batteries or USB, so a powered USB hub with MIDI would be better than using batteries when you don’t have it hooked to a computer.

Even some other synths like the Bass Station 2 allow for USB power and midi, so a powered USB connection like this would be cool for connecting a larger 61 key controller to it. Like the AKAI MPK series which is either USB midi/power or din midi with a barrel jack, but not both at the same time.

It is safe to say that there will be many more uses for this with a USB in and a USB out than I can personally think of! You may even be able to hook a CV pal to this with a USB out!

I third better mounting holes. If you are going to make a case, be sure to add those! :slight_smile:

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Cool thing!
Need one also.



The case I plan does not use any holes in the pcb (as you see above) - the two holes were actually just placeholders. Now I added 2 more in the back.

I’m wondering if there is somebody out there who would volunteer as a beta-tester? Preferably in Germany or Europe and with a certain number of USB MIDI controllers of different brands.