userfriendly's MegaDrum build

[userfriendly]

Alright, this first post doesn't contain much. Sorry for that. I plan to document my progress (or lack thereof) in this thread.

So friday the little package I was awaiting so impatiently finally arrived. Some time next week I'm going to my dad's (who has all the tools needed for the build) and start building this thing.

My MegaDrum parts so far:

• MegaDrum Kit 3 (with white-on-blue display)
• 19" rack casing 1U black
• 17 TRS input jacks
• 4 nickel pushbuttons
• 1 Heavy duty On/Off switch

I'm going to use only USB, so no MIDI I/O needed.

[Thud]

Congratulations.

Please keep us posted of your progress. Like to see it when you've got photos.

Thud

[userfriendly]

Right. First update.

My first mistake: I got myself a casing made of steel, not aluminium. Hey. Beginner's mistake, right? Right? So, as a result my dad was cursing a wee bit while drilling the holes for the input jacks today. And made sure I'm going to get me an aluminium front plate before the thing goes into the casing.

The soldering part went rather easy, although I do suspect that I screwed up one or two joints there. Going to test the whole thing with a multimeter before I fire it up. Wasn't quite sure about one of the resistors (R lcd), but a quick use of the search function here revealed that each type of display needs a certain resistor, in my case it was the white on blue display, requiring the 100 ohm thingie that I first thought was redundant (the PDF listed 2 of them, the kit came with 3). Other than that, assembling the PCB was a breeze, thanks to Synthex's good work.

My Jobeky hihat & controller arrived yesterday, so hihat is going to be the first thing I'll test once I confirmed that my MegaDrum unit itself is working alright.

Going to finish the job on Sunday (or so I hope) - will make some pictures then, too.

Well, that's it for now... good night & good luck.

[userfriendly]

So I finished the build, sort of - I now have it hooked up to a Windows machine, and the LCD hooked up to the PCB.

Now something strange is happening: Windows does detect it correctly as USB Audio device - for a couple seconds. Then the device disappears from the device manager again. Only to reappear a couple seconds later. Disappears again. Appears again. And so on. The LCD shows the vu meter screen and nothing else.

Any hints what could be wrong with it?

[dmitri]

http://www.megadrum.info/forums/viewtopic.php?f=3&t=268

[userfriendly]

My apologies. It's unclear to me how this thread you linked to is related to this problem. Do I have to solder a resistor between VCC & Pin 26 of that IC?

I plug it in, the logo shows for a bit, then the LCD goes to show the VU meters. That part seems okay, no? It's just Windows that keeps repeatedly detecting and, err... undetecting the device.

[userfriendly]

the first time until it becomes "undetected" is a bit longer than the subsequent interval of detect / not detected. could this have to do with a capacitor?

[dmitri]

My apologies. It's unclear to me how this thread you linked to is related to this problem. Do I have to solder a resistor between VCC & Pin 26 of that IC?

You have a USB instability. PIC182550 handles USB hence I pointed you to this thread. If you use Synthex's USB firmware you can try to pull pin 26 of PIC18F2550 to Vcc over a resistor. If it doesn't help, you will have to use my USB firmware and pull pin 26 of PIC18F2550 to the ground over a resistor. Just as I advised in the above mentioned thread.

I plug it in, the logo shows for a bit, then the LCD goes to show the VU meters. That part seems okay, no?

This is how it should be.

[userfriendly]

If you use Synthex's USB firmware you can try to pull pin 26 of PIC18F2550 to Vcc over a resistor.

Thanks very much. All clear now.

This is how it should be.

Thanks again.

[userfriendly]

Yup. That sure did it. Now it stays detected.

Off to connecting the inputs...