Questions about MegaDrum

[sumpm1]

Hello. I ran across the MegaDrum project a couple of days ago and have since read the entire forum and seen the progress that is being made on this project. I must commend Dmitri and Synthex for contributing to such a great project.

I built a diy edrum set 6 years ago and bought an Alesis D4 sound module to control it. I intended on hooking the D4 to my soundcard for use with a software sampler. I always thought that $150 minimum was kind of steep when you intend to connect triggers to computer anyways. Since then I have bought a house, and an acoustic set. So my edrum set is retired and dusty, but I would like to resurrect them for a friend. Plus, the MegaDrum is too good to pass up!! So I will sell the Alesis and build a MegaDrum. I have a few questions though.

1. I have minimal electronics experience, will I likely be able to assemble the MegaDrum?
2. I saw schematics for the "digital board" and the "analog board." These are not 2 different MegaDrum versions correct? Is the "analog board" simply the board that connects to all of the physical trigger inputs?
3. I would like to build a minimal MegaDrum. I need maybe 16 inputs, NO LCD, NO Keyboard, NO Midi IO; Just usb for computer use. Is this possible to build? Would it require new schematics, or just follow same schematics omitting unecessaries?
4. I saw the new "plug and play" MegaDrum (thanks Synthex). Would this version still require some kind of programming of the chips?


Thanks

[Synthex]

I must commend Dmitri and Synthex for contributing to such a great project.

Thank you very much !
And thanks to Dmitri for creating this project !

1. I have minimal electronics experience, will I likely be able to assemble the MegaDrum?

If you know how to solder electronic components, it should not be a problem.

2. I saw schematics for the "digital board" and the "analog board." These are not 2 different MegaDrum versions correct? Is the "analog board" simply the board that connects to all of the physical trigger inputs?

The "digital board" is the brain module.
The "analog board" is connected to the different pads and sends informations to "digital board".
There are currently two version of MegaDrum : MegaDrum8 and MegaDrum32.

3. I would like to build a minimal MegaDrum. I need maybe 16 inputs, NO LCD, NO Keyboard, NO Midi IO; Just usb for computer use. Is this possible to build? Would it require new schematics, or just follow same schematics omitting unecessaries?

You can just omit components that are not needed.

4. I saw the new "plug and play" MegaDrum (thanks Synthex). Would this version still require some kind of programming of the chips?

You need to program the chip 18F2550 ("plug and play" version).
You must program the two components (Atmega and 18F2550) with two different cables. They are provided with schematics.

Good luck !!

[dmitri]

1. I have minimal electronics experience, will I likely be able to assemble the MegaDrum?

Ask yourself these questions: Can I hold a solder iron steadily? Can I read and, to some extent, understand schematics (e.g. that all Vcc's are actually connected together)? Can I spend some time on this?
If all the answers are 'yes', than you certainly can build MegaDrum!
If you cannot understand schematics you can still build it yourself if are able to find some place to have a PCB made for you so that you just solder all the bits in places.
Or, if you have a friend with those skills, maybe he/she?! will be willing to make it for you?:)

2. I saw schematics for the "digital board" and the "analog board." These are not 2 different MegaDrum versions correct? Is the "analog board" simply the board that connects to all of the physical trigger inputs?

You are correct.

3. I would like to build a minimal MegaDrum. I need maybe 16 inputs, NO LCD, NO Keyboard, NO Midi IO; Just usb for computer use. Is this possible to build? Would it require new schematics, or just follow same schematics omitting unecessaries?

You follow the schematics and just omit the LCD, the keyboard and and the 6n138 (and all around it).
In fact, estregan from this forum did just exactly this and you can ask him about his experience.

4. I saw the new "plug and play" MegaDrum (thanks Synthex). Would this version still require some kind of programming of the chips?

Synthex's MIDI USB board is now actually a recommended way of connecting to a computer. Both Atmega32 and PIC18F2550 will need to be programmed. And both of them can be programmed with simple LPT/COM cables with only passive components (resistors) required.
Although I designed MegaDrum to be very capable, from the beginning I meant MegaDrum to be simple and inexpensive to build. So, think about it, and if, after all, you decide to build it I wish you good luck!

[sumpm1]

Thanks for the quick replies guys. That was kind of crazy though. I posted, left for work, and when I returned, the forum looked different!

[Goldie]

Same here, i dont know much about electronics, soldered couple of guitar cables before, but i've learned lot in 10 days, you need time for that. you have 2 options:

1. Print finished PCB layout, make pcb-s, buy parts and assemble, and dont learn thing. Maybe you dont need to learn anything, and just wanna start playing

2. This is one i choose. Take some old piece of electronics and experiment. Try to unsolder something, try to recognise parts, drill some holes in it. Most of those small chips have standard spacing of 2,54 mm between pins. Try to solder it back. If you can, you can solder everything on megadrum. Analyse schematics and see what goes where and what it does. Once you've learned you'll be able to adapt design to suit your needs. I removed LCD, keyboard, usb, just MIDI IN/OUT left. Price for parts now is down to 31$ .

Start here:

http://www.kpsec.freeuk.com/components/resist.htm - basic knowledge of components. If you think you know this stuff, then I can't help you, ask someone better.

Download this software, you'll need it:

http://www.diptrace.com/download.php - DipTrace 1.40. All programs and all libraries. Full-featured 30-day trial.

And ask questions.

[zip1]

Goldie does have some very good suggestions here. I do have some experience dating back
to the 80's with experimenting with electronic's stuff. I have that same page printed and in a notebook,
and several other's for reference since I never memorized those codes.

Soldering of components is very important and you do need to practice that. Even if you attend advance
schooling for electronic. One of the courses is soldering, one of the first thing you do is de solder
components from board, then re solder them back to the same board.

I would suggest not doing Integrated Circuits at first but practice with the resistors and capacitors type
components first. If you do IC's do small one with low pin count like 6 or 8 pins. Anything larger requires
something besides a soldering iron to get them off.

Most of the chips used in this project are CMOS type chips. These types of chips can be ruined by static charges.
So any of the cmos devices like the processors of the 4051 should be in sockets. The chips should be inserted
last and you should at least touch the board before inserting them.