Jazzmarazz wrote:

How is your optocoupler wired up?

Like this:

Even if the optocoupler wasn't wired correctly, wouldn't midi out still work?

Thinking about this a little bit more, I suspect the 6n138 is having problems (among other things). Again, it doesn't make sense to me that midi out doesn't work either, but maybe there's more than one issue at play.

If I understand correctly, I should NOT be able to program the arduino when it's in any mode other than programmer (with all leds on). However, I am able to program it regardless of which mode I'm in. If I understand the code and schematic correctly, the 6n138 vcc is tied to arduino I/O pin 4 so we can control the power on the fly. I suspect that the opto is not getting power correctly. I will attempt to connect 6n138's vcc directly to the arduino's vcc and see if I get any better results from that.

Other than that, I am at a bit of a loss here. Help me Jazzmarazz, you're my only hope!

Hmm. Which arduino are you using? It might help to recompile the code for your particular board and reprogram it.

I'm using an Arduino Pro Micro. I did have to modify the code a bit because the pro micro doesn't have I/O's 11, 12, and 13 but instead it has 16, 14, 15 where they should be (compared to a pro mini). I'm sure that those led's are working though, because the startup sequence works correctly and I can cycle through the led's with no problem.

Did the opto circuit look okay to you?

Thanks a ton for your help btw. I really appreciate it!

Is the pro micro the 5v version or the 3.3v version?

Also, what is the purpose of Pin 7 of the 6n138? Half time I see it floating.

Last edited by Jazzmarazz (Jul 27, 2015 9:32 pm)

The pro micro is the 5v version.

Pin 7 is the base of the second transistor in the opto. I don't understand fully, but it makes the rise/fall time of the opto smaller. Adding the resistor there is suggested by Nitro2k01. http://blog.gg8.se/wordpress/2009/07/26 … -glitches/

So I built another one using a breadboard and an Arduino Max 2560 and I get the same results - nothing. I'm wondering if My midi gear isn't cut out for an arduinoboy? Has anyone successfully used a rockband keytar with an arduinoboy?

At this point I'd even be willing to ship it to someone who has known good midi gear to test for me.

Hey catskill did you work this out mate? I am also struggling to get midi in working when everything does. Cheers!

Blockhead wrote:

Hey catskill did you work this out mate? I am also struggling to get midi in working when everything does. Cheers!

I did. Basically go over the midi in circuit a million times to make sure it's wired correctly. Your opto may also be dead, so grabbing an extra may not be a bad idea. Also make dang sure your gb link cable is connected correctly!

I eventually made a diy kit out of these frustrations: http://catskull.net/shop/arduinoboy At $16, it might be worth saving you hours of frustration.