Gastric's MegaDrum build

[kimouette]

Gastric, you can erase everything we said since yesterday when I asked for the extra rim piezo advantages...

I have copied everything in my "A to E drum conversion" thread. You're right I shouldn't have asked these questions here!!

Delete everything! And thanks again for your patience!!!!!

[gastric]

Quick update as I've had a few people ask me about my build.

* I struggled with printing the board as has been well documented
* I did finally build the board, soldered everything on, but could not program the ICs
* As best I can tell the board has some issues though I have no idea what and stopped the project at that time as I only had a really cheap pocket multimeter that was suspect with it's readings as they would swing wildly likely due to the fact it is 100% auto-ranging
* I recently purchased a more robust multimeter to further my adventure
* But with the holidays and other unrelated projects on my To Do list this has been back burner'ed for a while, possibly until after the New Years

For any non-electronics people considering this project my overall recommendation would be to simply buy the V2.7 board and programmed ICs from Synthex. You can source the remainder of the electronic components elsewhere if needed, like Mouser.com

I haven't priced out the raw components for making a V2.5 board and programming cables but it's probably at least $25 worth of raw components between a copper clad board, acid, cable ends, etc. More if you have to buy a pack of printer paper which is probably $10 minimum. In contrast Synthex will sell you a V2.7 and both ICs shipped for $43 Euros, which is about $54 US. So for a mere $29 more you get a professionally built board (masked, the works) and save yourself a lot of effort.

By no means am I saying it's impossible to build a V2.5 board. And it may be educational, which it has been for me. But speaking purely from a time/effort and likely cost aspect buying the board and programmed ICs is probably worth it. Japi started his MegaDrum around the same time as me and I've seen him go through a ton of struggles along the way as well. I think he's nearing the finish line and as a fresh V2.5 user he'd likely be an excellent source of information as well.

And is what I'll be doing if I can't easily get my V2.5 working once I resume the project.

[japi]

I'm 99.9999999999999999999% sure that your problems to program de ICs are related with shorts in the pcb traces. I've found at least five in my build (i have documented one of them, very important, a short between vcc and ground). Those traces are so thin that a little movement when doing the transfer could lead to a little bigger trace that shorts with another that shouldn't.

Hope you can sort them out. We will be waiting further comments on your build. Good luck!

[Xmattz]

I confirm that using synthex 2.7 kit is really easy. I ve never soldered in my life, but it took about 3 hours to have the PCB ready and working. No chip to update, just plugged the usb and voila !

Good luck guys !

[gastric]

Fast forward to 2000, I purchased a V2.8 kit, spent a mere handful of hours soldering, and VIOLA! A seemingly working MegaDrum! WOOOO! I still have to test that all of the inputs and functions work, but the LCD displays, I get VU meters when testing the HH and Kick, the MIDI LED lights, the front panel buttons work, and the PC sees USB Audio Device.



Things left to tackle:

* Mount it all in the chassis (need to figure out how to mount board as standoffs aren't matched, mount LCD, and LED)
* Solder MIDI DIN connectors and connect to V2.8 board
* Get LCD to have backlight (I soldered no resistor yet, so I'm assuming it simply needs to be bridged for 5V which is what the LCD needs for power)
* Solder front panel on/off switch by interrupting USB VCC. I chose a LED on/off so hopefully it doesn't such power and screw something up
* Fully test all inputs
* Fully configure all triggers

Once everything is proven to work successfully I'll get to work on upgrading my crash cymbals to 2-zone so I have a working choke (and edge hit if my VST supports it).

I have to say, I wish I would have simply purchased a kit to begin with. I literally spent at least 20+ hours dinking with the V2.5, plus the associated costs, VS a mere handful to fully complete the v@.8 kit. Hopefully one of you will purchase my failed V2.5 kit so I can recoup some of my expense there.

[japi]

Congratulations!
Keep us posted!

[mojamusic]

Wow, great job. I'm inspired to get my project done (after almost a year).

[jman 31]

Man, I can't believe you took the easy way out! Congrats on getting the v2.8 going.

You should be able to make some standoffs pretty simply if you don't mind drilling some holes in the bottom of you case. Hardware stores usually have nylon bushings that run anywhere from say 1/2" to 2" long. You could use those as standoffs and then run a through bolt all the way from the bottom of the case, through the nylon bushing and then through the board holes. Or get some of these. Same principle sort of.

[gastric]

It's only "easy" because I spent 20+ hours on the V2.5 kit first.

In all seriousness, it's all about the board. Synthex's boards are solder masked so ONLY the pad you're soldering is exposed. With the V2.5 there's exposed copper everywhere which makes it easier for a sloppy unskilled solderer to make a mess. Not to mention the difficulty troubleshooting board issues on such a compact, tiny, chock-full-O-components PCB.

I'm certainly not knocking the V2.5 But I personally will recommend the kits to anyone that asks. You still have to do a lot of reading, understanding, soldering, and chassis construction as it is.

I should have everything soldered and attached to the chassis in the next week or so, then I'll get to work on testing and configuring all my triggers with it which I'm sure will be another adventure.

[gastric]

Everything's in the chassis and working. I still need to:

* Connect MIDI DIN
* Connect front power switch
* Attach rack ears and mount in the rack
* Potentially install a resistor to the LCD, it's extremely bright. Currently just a wire to bridge the LCD backlight connections on the board. It's a 5V LCD so I'm assuming that's fine.
* Last, but not least, fix my HOT pads.

Issues I encountered with the chassis installation.

* Difficult to cut perfect edges around the LCD. May look into some automotive trim or something to snap onto the edge.
* Mis-measured 1/4" jack holes so they were a little too close. I had to mix-n-match some jacks, and stick the MIDI DIN in the middle, and still have one unused hole.
* Just epoxied the USB jack to the chassis and cut an access hole, same with the front LED. Seems solid.
* Accidentally mounted the board to the TOP of the chassis instead of the bottom. Classic 11pm mistake. Not that it matters, but gravity could loosen wires plugged into the board over time.