Circuitbenders Forum
Circuitbenders Forum => Circuitbending discussion => Drum machines => Topic started by: gmeredith on January 23, 2008, 03:28:56 AM
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Hi everybody!
I just recently bought a set of Casio DP-1 drum pads - the yellow dual hexagonal ones in a rectangle frame. I'm going to get more of these and build up a really kitsch electronic drum kit, to use with my Roland PM-16 Drum MIDI interface controller and Dr660 drum machine.
I presume that the casio pads are actually not real piezo sensor type pads that output a velocity pulse, but only a switch type mechanism that closes a contact. Has anyone converted one of these in the manner of which I describe, for some advice? I'm going to put flat piezo sensor discs in each pad, but until I get the pads (still on delivery) I was wondering what they look like inside, and how I would mount the sensors.
Cheers, Graham
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You are probably right about the possibility of switches in those. The drum pads on my MT-500 sound the same whether I just barely touch them or smack them hard.
Sorry, I don't know about how to replace the switches with piezzos.
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Yeah, i pretty much figure they're just switches. I basically know how to install the piezo sensors, I was just hoping that someone had already done this, so as to give me a clue on the best positioning, and what cutting/mounting they had to do. My pads arrive next week, so until then, I can only speculate.
Cheers, Graham
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Probably just switches.
How much did you pay?
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$25 brand new in box old stock for 2 pad units (each unit having 2 pads in it). I thought that was pretty ok.
I found a small post somewhere in a google search last week of a guy who said he put some sensors in his so he could use them with his alesis DM5 drum brain or something like that. Can't seem to find the post anymore, otherwise I'd ask him what he did...
Cheers, Graham
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Well, I just got my pads in the mail, woo hooo!
I've now installed the piezo sensors in them - a really easy job!! Now they can be plugged into any standard drum brain unit such as a Roland TD series, Alesis DM5 or Yamaha units and play them just like standard electronic drum pads!
They are amazingly responsive and versatile. They are just the right size to sit on your lap and play them with your hands like bongos. They also come with standard drum stand mounting clamps. The hexagonal rubber pads are a really good size - not too large, but not so small that you keep missing them when you use sticks. The rubber feels really good, too - great stick bounce and low surface noise.
If anyone wants to try the same mod, here is the piezo sensor I used:
http://www.jaycar.com.au/productView.asp?ID=AB3440&CATID=15&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=291
They're only a couple of dollars each, and when you remove the sensor disk itself from its plastic casing its only about 1mm thick. You can then slip 1 of these in between the 2 rubber pad layers of each pad. Fasten them with a small strip of gaffa tape - that's all it takes! Now you just solder the existing wires in the cable to each sensor disk terminals, put them back together and start pounding away!!
Cheers, Graham
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Hi Graham.
I just got my pair of casio dp-1s. I am going to install the piezos like you posted but had a question. when you sodder the piezo to the connectors do you still route the signal out of the DP-1 through the original 1/8 cable to a drum machine? are both pads triggered through the one cable? I am not sure how both pads would be assignable to different sounds in the back of a drum brain.
thank you
matt
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Hey, sorry for not noticing your question for this long!
Yes, both pads are used through the original 1/8" cable. You then simply make a 1>into 2 Y-dadpter cable using a 1/8" stereo mini jack socket to split it into 2 separate leads, with 1/4" mono plugs on each end, which then plug into your drum brain module.
Having said that, some drum brain modules have STEREO input jacks for triggereng pads with more than 1 sensor - I think some of the Alesis ones do. In this case, simply buy a stereo 1/8" to stereo 1/4" adapter for the end of your casio cable. You can then assign a different sound to each pad.
Cheers, graham
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Hi, all!
Sorry for the late hit on an old thread. I found this thread while investigating the possibility of using my DP-1s to program my RZ-1 instead of the awful hard plastic "pads" on the RZ-1. This led me to buy an Alesis Trigger IO and additional pads to max out the inputs on the drum brain. I have a total of 13 DP-1 units. I plan to keep the best 10 of them for my drum kit, and possibly modify them as Graham did his.
I want to use a combination of stereo adapters and cords to split the DP-1 triggers between the Trigger IO and three old Casio "Super Drums" keyboards. Here are the adapters I've chosen (ten of each):
1/8" -> 1/4" TRS plug adapter to fit DP-1 plug to brain head (MPJA part #11307 AD)
1/8" TRS jack -> (2x) 1/8" TRS plug Y-adapter to split triggers (MPJA part #11426 AC)
12 ft. 1/8" TRS jack -> 1/8" TRS plug extension cord for flexible gear placement (MPJA part #11291 CB)
My question is, if I convert the pads to piezo, will they still be able to trigger the older Casio keyboard drums?
The full drum kit will include:
10 Casio DP-1s
Casio RZ-1
Casio MT-540
Casio MT-500
Casio MT-220
Casio MT-205
Alesis Trigger IO
Alesis MMT-8 sequencer
MOTU Micro Lite MIDI interface
Fostex MR-8 recorder
Behringer UB1202 mixer
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Oops, wrong thread.
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Graham, do you remember the manufacturer's name and part number for the piezo transducers you used? I'm thinking about trying these from a US distributor, but I'm not sure they'll work:
http://www.mouser.com/Search/ProductDetail.aspx?R=AT-3045-TF-LW110-Rvirtualkey66500000virtualkey665-AT3045TFLW110R (http://www.mouser.com/Search/ProductDetail.aspx?R=AT-3045-TF-LW110-Rvirtualkey66500000virtualkey665-AT3045TFLW110R)
Thoughts or suggestions?
Thanks,
Jim
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Sorry for not replying...a new baby is keeping me away from the computer lately!!
Yes, that transducer is like the one I used and should work fine.
Regarding use of the pads as trigger and also for the super drums keyboards, you could possibly use them for both if you put in the piezo sensor UNDERNEATH the rubber sheets instead of between them, and run a completely separate cable and plug from them rather than disconnect the casio's original cable - that way they will still work as switches using the originals (for the super drums) and also as triggers using the extra cables.
Cheers, Graham
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Graham, do you remember the manufacturer's name and part number for the piezo transducers you used?
When I built pads I just used whatever piezo transducers Maplin had. IIRC they were about 60p each, and about 40mm across.
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I ended up using the ones from Mouser, and they work great! I'm waiting for more solder to arrive so I can mod the other twelve units.
I think Graham is right about putting the transducers under both rubber pads vs. between them. The plastic housing allows too much crosstalk. This can be mitigated somewhat with Trigger IO settings, but that tends to mess with the dynamic range. Putting them directly against the wooden base should help reduce crosstalk between pads.
To answer my earlier question: you cannot use the modified pads with the old school Casio keyboards they were made for. Both pads trigger the same sound for some reason. Moreover, the small pads built into the keyboard's console won't work when the modded DP-1s are plugged in. That doesn't matter because I have some SS-1 sound sticks to use with the older keyboards.
Note that I did not disconnect the original switch connections, so I guess I have the switches and transducers wired in parallel now. I'm not exactly sure how to disconnect them.
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Yes, that's where you will need to have 2 completely separate cables if you want to run both the old setup and the trigger setup. It should be pretty simple to do; just take an unmodified pad set that already operates the super drums keyboard and don't change its wiring - leave it. Then install the piezo sensors under both rubber mats as per mentioned, and run a separate cable in through the casing for them parallel to the original cable. if you got clever you could even then replace both of those individual cables with a single 4-core cable and wire them like the 2 separate ones for neatness if that mattered.
Cheers, Graham
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I think I would run both setups through a DPDT switch and out the same cable if I decided to go the dual-trigger route. It doesn't matter much that they don't work with the old keyboards, as I still have the SS-1 drumsticks for that.
Would I get more sensitivity if I disconnect the original switches, or does that not have anything to do with it?
Thanks,
Jim
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You don't have to disconnect them if you use the dpdt switch setup, so that at any time either the piezos are operating OR the pad switches are operating, but not both (eg running in parallel connection simultaneously). Actually your switch idea is a very simple and elegant way of doing it - it would function as a "mode" switch.
Make sure the switch does the switching to piezo mode so that it doesn't include the resistors in the piezo line, otherwise you won't get as sensitive output from the piezos.
Cheers, Graham
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Graham,
To clarify, are you saying that having the switches and transducers hard-wired in parallel does affect the sensitivity?
Thanks,
Jim
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Well, after thinking about it a bit more carefully, it shouldn't interfere with the piezo output, so long as you parallel connect the piezo's +ve wire AFTER the resistor on the switch line wire, not before, so that the output of the piezo doesn't have to go through the resistor to go out of the cable. It then shouldn't diminish the output. And then you won't need a DPDT switch to change modes - just plug it in and start using it.
HOWEVER, connecting the piezos to the super drums wiring in parallel MAY interfere with the pads when used for the original function for super drums keyboards; because here, you are wanting to use the rubber mats as mechanical switches, and you have a piezo element bridging that rubber switch permanently already. Piezos have very high resistances and I should think that they would probably not interefere too much with the keyboard drum signal that is being switched by the rubber pads, but try it out in super drums mode to see. If you get erattic firing of your super drum sounds then you may have to put in the dpdt switch to stop the piezos interfereing with them.
cheers,
Graham
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I don't see any resistors inside the unit. I wired the transducers directly to the output cables by soldering their leads to the same joints where the cable wires are soldered to the board. If the original trigger switches go through a resistor somewhere, then they are definitely on the opposite end of the resistor from the transducers.
I didn't have any solder when I did this, so I attached the transducers by melting the solder that was already on the board. There wasn't enough solder on the joints for both wires (transducer and cable), and one of transducer leads subsequently broke away from the solder joint. The solder I ordered finally arrived yesterday, so I'm going to re-attach it and place the transducers under both rubber pads. I'm hoping the wooden base will dampen the vibration and reduce crosstalk between pads.
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Well, what do you know? The newer units have resistors soldered to the cord leads. The older ones don't. I'm going to test my new layout on the older one that I'm reworking. If all goes well, I'll just remove the resistors from the newer ones.
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Well there you go, I didn't know that either! You won't need to worry then on your old set. And you know what I'm talking about now regarding the new set. I don't know why they put the resistors in the newer ones - maybe they had false triggering issues with the older pads or something. Hope you get them working the way you want. I've just got to mounting all of mine (8 units) onto a mega drum rack frame with an old Roland drum pad for the snare, and the casios for the others/cymbals, running into a Roland PM16 drum interface unit, driving a boss DR660 drum machine for sounds. Really rocks!!!
Cheers, Graham