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DIY Stompboxes => Digital & DSP => Topic started by: Steviebabes on February 11, 2019, 03:56:58 PM

Title: Midi CC to PC switching interface
Post by: Steviebabes on February 11, 2019, 03:56:58 PM
Hi,

Has any one built or considered building a CC to PC converter?

I've got a Boss GT 100 and it can only send PC changes when you select a patch.
My Blackstar Series One Amp happily receives PC changes.

The Boss can send CC messages from within a patch  and what I'd like to do though is change amp channels from within a patch.

It can be done with a Midi Solutions Event Processor (http://midisolutions.com/prodevp.htm)

It would be quite nice to do it as DIY box on something like an Ardurino :)

Can anyone point me in the right direction??

Thanks in advance
Title: Re: Midi CC to PC switching interface
Post by: ElectricDruid on February 11, 2019, 06:08:31 PM
That should be simple to do with an Arduino. You'd need a MIDI shield of some sort (haven't looked, but there must be plenty of those). There's certainly library functions that do most of the MIDI nitty-gritty for you. After that, it'd be a question of keeping track of what's coming in, spotting the message(s) you're interested in, and sending the other one(s) instead.

Eminently do-able. Go for it.

HTH,
Tom
Title: Re: Midi CC to PC switching interface
Post by: Ben N on February 12, 2019, 03:46:10 AM
... You'd need a MIDI shield of some sort (haven't looked, but there must be plenty of those).
Easy enough to roll your own, too. Coupla 5-pin jacks, optocouplers, and resistors, and a bit of perfboard, and wahla.
Title: Re: Midi CC to PC switching interface
Post by: potul on February 12, 2019, 08:40:58 AM
It's a perfect project for a small arduino. You don't even need any shield, just some resistors and an optocoupler will do the trick.
There are a couple of MIDI libraries ready to be used that you can grab.
You can take my MIDI Switcher project as a starting point, and change the relay control for a MIDI OUT function. The hardware is even there (both MIDI OUT and IN), although I only used MIDI IN in the software

https://www.diystompboxes.com/smfforum/index.php?topic=112424.0 (https://www.diystompboxes.com/smfforum/index.php?topic=112424.0)

I can help with the software changes, drop me a message if you want me to help.

Mat
Title: Re: Midi CC to PC switching interface
Post by: ElectricDruid on February 12, 2019, 03:29:19 PM
... You'd need a MIDI shield of some sort (haven't looked, but there must be plenty of those).
Easy enough to roll your own, too. Coupla 5-pin jacks, optocouplers, and resistors, and a bit of perfboard, and wahla.

It is indeed. The general IN/OUT/THRU schematic looks like this:

https://electricdruid.net/wp-content/uploads/2016/04/MIDISchematic-3.jpg (https://electricdruid.net/wp-content/uploads/2016/04/MIDISchematic-3.jpg)

Title: Re: Midi CC to PC switching interface
Post by: Steviebabes on February 12, 2019, 05:54:28 PM
Hi Guys,

Thanks in advance for the offers of help  - I've ordered some bits and will be back in touch when they arrive :)

I'm a bit confused, will I need the opto - isolators or can the Midi sockets connect straight on to the board?

Steve
Title: Re: Midi CC to PC switching interface
Post by: ElectricDruid on February 13, 2019, 08:47:00 AM
In order to meet the MIDI spec, the IN needs an optoisolator. Since all MIDI Inputs are opto-isolated, there's no need for outs or thrus to have optos.

In fact, you can wire a MIDI OUT from a processor with just a plug and a couple of resistors. It can be fantastically simple. The IN circuit is always more complicated.

HTH,
Tom
Title: Re: Midi CC to PC switching interface
Post by: potul on February 13, 2019, 10:32:21 AM
Hi Guys,

Thanks in advance for the offers of help  - I've ordered some bits and will be back in touch when they arrive :)

I'm a bit confused, will I need the opto - isolators or can the Midi sockets connect straight on to the board?

Steve

You need it for MIDI IN. Take a look at my project, you have a midi in and out already there using a 6n138 opto. With this and 4 resistors you have both midi in and out setup.

(http://i471.photobucket.com/albums/rr74/mateu_ros/midiswitch.jpg)