www.megadrum.info

*** UPDATE March 22, 2008 ***

MegaDrum MIDI Trigger - 32 triggers inputs - Full USB2 plug'n play - MIDI DIN connector (In and Out) - LCD screen - Keyboard - And much more ...


NEW VERSION : http://www.megadrum.info/forums/viewtopic.php?f=3&t=187


Hello,

I sell some kits containing a "All In One" PCB and all ICs :

- 1x All In One PCB
- 1x Programmed Atmega32-16PU
- 1x Programmed 18F2550 USB 2.0
- 4x MAX4558





Professional achievement :
- 140 mm x 70 mm with mounting holes
- Top Silk Screening
- Green Solder Mask


Fully USB plug'n play, works with all Windows like XP and Vista, Mac OS, Linux, ... (Fully USB2 compliant)
Inputs of this kit are protected against ±15kV electrostatic discharge (ESD) shocks (Fully IEC1000-4-2 compliant)


The price of the kit is 55 euros (about 80 USD).
This price include shipping (Registered Airmail) anywhere in the world.
The payment may be made by PayPal.


Here is the list of components to be purchased in addition to the kit and pinouts :




----------------------------------- NEW -----------------------------------

The new 2.7 version is available here : http://www.megadrum.info/forums/viewtopic.php?f=3&t=187


Very professional achievement :
- Double Layer
- Copper Thickness 70 um
- 145 mm x 70 mm with mounting holes
- Top Silk Screening
- Blue Solder Mask
- More features : USB connector on board, Optional external alim, pullup resistors, ...

The new kit is :

- 1x New All In One PCB v2.7 double layer
- 1x Programmed Atmega644-20PU (or Atmega32-16PU upon request) with bootloader
- 1x Programmed 18F2550 USB 2.0 (MIDI Device VISTA Ready)
- 4x MAX4558
- 4x 74HC4851
- 1x 6N138

----------------------------------------------------------------------------


Someone is interested ?

Please send me a PM (Private Message)


Regards,
Synthex

Nice PCB design! Do I understand right that with 74HC4851 or MAX4558 you don't need current limiting resistors?

I looked at the 74HC4581 datasheet and from "Application notes" it appears that current limiting resistors are still needed.

dmitri wrote:I looked at the 74HC4581 datasheet and from "Application notes" it appears that current limiting resistors are still needed.

74HC4581 ?

dmitri wrote:I looked at the 74HC4581 datasheet and from "Application notes" it appears that current limiting resistors are still needed.

With your 100 ohms resistor, current can reach 50 mA !
The 100 ohms resistor is for electrostatic discharge shocks (ESD).

100 ohms and 4.7 Kohms resistors (before the Atmega) limit the current.
And a piezo element can't produce much power

Obviously I meant ESD. So with 74HC4581 we don't need ESD protection resistors?

dmitri wrote:Obviously I meant ESD. So with 74HC4581 we don't need ESD protection resistors?

Yes !

From the 74HC4851 datasheet :

"ESD Protection Exceeds JESD 22 :
2000-V Human-Body Model (A114-A)
200-V Machine Model (A115-A)
1000-V Charged-Device Model (C101)"

dmitri wrote:Obviously I meant ESD. So with 74HC4581 we don't need ESD protection resistors?

And if you ask me for MAX4558 :

"ESD-Protected X, Y, Z and X_, Y_, Z_ Pins
±15kV (Human Body Model)
±12kV (IEC 1000-4-2, Air-Gap Discharge)
±8kV (IEC 1000-4-2, Contact Discharge) "

Excellent! It makes building MegaDrum even simpler!

dmitri wrote:Excellent! It makes building MegaDrum even simpler!

Of course !
Then, is someone interested ?