Resistor & diode questions.

[WizardOfWoo]

Legend thank you.

I just realised you are the same guy who made the 3 zone cymbal I have been eyeing up too. So thank you for that idea as well! (mercifully no real questions on that front).

[ignotus]

Hi, as promised, here's an all-in-one PCB by Dmitri that's a few years more recent than the other one by Synthex, including a component list. Hope it's of use.

[WizardOfWoo]

Wonderful thankyou!

If you don't mind me asking. I saw you mention making a really neat cymbal choke with a guitar wire on a vrdums thread.

Is that really as simple as just wiring it to the 2nd input like it was a piezo? No resistors and whatnot?

Unfortunately most the vdrums links i follow for details are dead now.

[ignotus]

If all you want is to add a choke function (i.e. single zone + choke cymbal), yes, a guitar string or any conductive surface will work without any additional components. You set the second zone to 'switch' and find the threshold value where it gets activated by just touching it. I used that for years until I made the 3-zone cymbals.

[WizardOfWoo]

I want to make at least a Hat and a Ride with your 3 zone method. (are they still holding up well after all this time?)

But for most the regular crash and splash's I'm looking more for compact and simple.

That method of single zone with a choke will do nicely thank you.


Looking at that board. It has extra eprom memory? and then more inputs & multiplexers?

Oh and an off switch.

Glad I held off ordering parts

Is the 56 inputs still supported on the AT644? I seem to remember reading something about it no longer being so? But now I'm questioning if I made it up because I can't find it again.

[ignotus]

Yeah, it has extra eeprom, hadn't noticed that.

It's a pcb for 56 inputs. You can just leave out the multiplexers for the inputs you don't need/want. I think the atmega644 is limited to 48 inputs in current firmwares, so at least one multiplexer can be left out.

I made 5 cymbals and one of them (ride) has started acting up (sometimes refuses to register hits), though it should be easy to fix - I think it just has a faulty connection somewhere. Otherwise they're all still working. The vinyl has started to crack in places but it's just decorative so it doesn't really matter. The best design change I made was to bolt them together and not glue them, so they can be repaired and theoretically be maintained to last a very long time.

[WizardOfWoo]

Yeh I was really impressed with the design. Very little to go wrong unlike some of the convoluted floating bell's and stuff I've seen others trying. (or trying to isolate and dial out crosstalk from multiple triggers....nope).

Also, I was thinking about LED lit buttons for the front. Can they just piggyback off the keyboard pins/wires? Or will I need to splice in 3-5v from somewhere else? (and if so can you please recommend where)

Sorry if these are dumb questions, I'm just worried about drawing too much power from something that isn't built to take it.

[ignotus]

Yeah you can use a 5v source from anywhere on the board, there are many places to get it from and it doesn't really matter. I used a couple of backlit buttons and no problems there. If you scroll down you can see it here.

[WizardOfWoo]

Ok thank you so much for your help.

Your module looks really nice. Same sort of buttons I had in mind.

[WizardOfWoo]

Sorry to bother you again; can I just confirm if this PCB uses the same pinout scheme as Dimitri's current kits?

i.e (40 being top left on the PCB.pdf)

40-39 Pedal power/low
38-37 Pedal high/kick
36-35 Hat/edge
34-33 Snare/rim
32-31 Ride
30-29 Crash
28- 22 Tom1-4
20- 17 Aux 1-2
16-15 Ground x2
14-48 Aux 3 onwards

Also, am I right in thinking I can just omit the high impedance hat input if I only intend to use a DIY Hall sensor? (i.e. it's just for special Roland/Yam/whatever?)