My MEGADRUM32-SMD pictures

[Aaron]

Aaron, you have trimer for contrast, right? If so i think ill use one too. Cheaper and you wont tune it every day. Maybe make little hole for small screwdriver.

yes!, thats what your suppose to use.

you dont need a hole you only set it once.

[TriggerThis]

Great work !

I'de like to know wich voltage regulator you used ?

Since I'm not interested in the USB connectivity I need an alternate power source. A 9 or 12 volts plug-in is easy enough to find for around 5$, so I was going to use a LM7805 to get the 5 volts to the boards. I was wondering if it is what you are using, I never seen a surface-mount LM7805 so I cant really say just by looking at the photos.

Also, would you be willing to share your version of the PCB ? (sorry, but I had to ask)

[Aaron]

the reg is a "Recom R-785.0-0.5"
its a miniture switch mode power supply.

you can replace it with a 7805 wich is cheaper.

i will provide the board drawing to anyone interested, but i have found
that there are not many hobyists that can assemble SMD, plus its double sided.

[elrules]

aaron, what is that polyfuse for protecting 5v hihat controller??? Is that piece on the dmitri schematics? When I have seen it on your photo I felt scare cause I have a VH-11 controller that cost me 300 euros so I don't want to toast it.

Please, give me a light on this

[Aaron]

aaron, what is that polyfuse for protecting 5v hihat controller??? Is that piece on the dmitri schematics? When I have seen it on your photo I felt scare cause I have a VH-11 controller that cost me 300 euros so I don't want to toast it.

Please, give me a light on this

its a self resetting fuse to protect the megadrum from short ect..

no its not on the schematics, we have made a few changes.

like adding the regutator, caps on the inputs and bat54s diodes.

[TriggerThis]

its a self resetting fuse to protect the megadrum from short ect..

no its not on the schematics, we have made a few changes.

like adding the regutator, caps on the inputs and bat54s diodes.

You added capacitors in series with the 100 ohms resistors on the inputs -- thats what it looks like on the photo. Why ?

[Kartman]

The capacitors go from the mux side of the 100R input resistors to ground. This is to offer some ESD and EMI protection. The schottky diodes are not rated for ESD, so they needed some protection. The capacitor value was guessed at 100pF as the 100R/100pF combination will knock the edge of most ESD transients. As to whether the 100pF affects the intended operation of the board, I don't know. Maybe Dimitri can comment on this.

The board will probably comply with CE industrial emissions but I didn't go overboard for compliance as it was just a quick lash-up.

[dmitri]

The capacitors go from the mux side of the 100R input resistors to ground. This is to offer some ESD and EMI protection. The schottky diodes are not rated for ESD, so they needed some protection. The capacitor value was guessed at 100pF as the 100R/100pF combination will knock the edge of most ESD transients. As to whether the 100pF affects the intended operation of the board, I don't know. Maybe Dimitri can comment on this.

100pF is too low value to effect input signal from piezos/switches so it should not effect MegaDrum functionality. I may add these capacitors to schematics as an option to better comply with ESD/EMI.