PCB for Drum Trigger
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Does anyone out there want to make a PCB for the 4066 drum trigger circuit? I'm teaching a workshop for high schools to build these and we could use a PCB. I could pay for the PCB.

-Tom
Posted by Tzim on March 24, 2009 at 16:38:32 Pacific Time

Alesis SR 16
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So I have an Alesis SR-16 Drum Module and I was wondering if it could be turned to the same use. I cracked it open and it seems to have 2x the number of piezo elements as the module in the article. I understand the article pretty well. The only problem I have is that the board circuits that are trigger the drum sounds look considerably different than the ones in the Zoom. Is there any way you can suggest what the best way to soldering on to these circuits would be? I have images. Thanks.

Posted by r05c03 on March 10, 2009 at 08:03:52 Pacific Time

Alesis SR 16
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You're doing great. Use fine sand paper to rub off the carbon (black) of the drum finger traces (where the switch touches the circuit board) until you see shiny copper, then solder #30 solid wire (used for wire wrap) to each trace.

You don't need the Pad Bank and and Function buttons the Zoom drum machine has. Just used these channels of the 4066 for additional drum pads. The Alesis has 12 drums so you will need 3 4066 circuits.
Posted by Tzim on March 24, 2009 at 16:36:07 Pacific Time

Alesis SR 16
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**** UPDATE ****

I just looked at my schematic designed for the ZOOM drum machine which takes advantage of the fact that the trigger circuit has a common ground. The Alesis and other drum machines might not have a common ground so let me give you a general solution that should work for all drum machines.

The 4066 has 4 switches. Here are the pins for each switch

Switch A pin 1 and 2
Switch B pin 3 and 4
Switch C pin 8 and 9
Switch D pin 10 and 11

Find the two traces for each drum switch that when shorted together with a wire causes the drum to sound. Wire each pair of traces to a switch in the 4066, i.e. connect switch A (pin 1 and 2) to your first drum switch pair of traces, switch B (pin 3 and 4) to your second drum switch pair of traces, etc.

-Tom

Posted by Tzim on March 10, 2009 at 13:03:52 Pacific Time

Alesis SR 16
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Okay, So I have been looking at the SR-16 and comparing it to the MRT38, If I understand you right, I need to connect TWO wires to the TWO traces for each pad (the traces being identified by triggering by shorting them). This is in contrast to soldering ONE wire to each "dot" for each pad on the Zoom. And I think I see the trace which you refer, though I have not tried to trigger them yet (I need to find the power adaptor (I know I have it somewhere, but the SR-16 does not use batterie). I can clearly see that there are two sets of pads for each drum button.

Also, you mention soldering wires to the Pad Bank and Function buttons. Not being familiar with the exact function of these buttons on the Zoom, I can only guess which pads use the SR-16 (I actually do not know much about how the SR-16 works as I have not used it much, favoring another drum machine for studio work). I imagine that the Drum Set button is roughly analogous to the Pad Bank, but I clueless as to the Function button.

I believe that I will need 3 4066 chips for the 12 drum buttons and I will need 3 "drum tubes" one for each piezo element. Is that right?

Lastly, I have attached two links of to photos of the board. Please note that the circuit board is inverted in the photo relative how it would be siting if it was in the frame and being used. You can clear see the pair of pad for each drum button

https://dl.getdropbox.com/u/381767/Alesis%20PCB%202.jpg

https://dl.getdropbox.com/u/381767/Alesis%20PCB%203.jpg

That is all I have for now. As soon as I find the damned power adaptor I will make some more progress. Thanks for your help.

Posted by r05c03 on March 19, 2009 at 11:48:26 Pacific Time

Alesis SR 16
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Hi there,
Are you still working on the project? how far have you come with that? I have uploaded the photos on the link. http://photobucket.com/diyjesus_edrum

there is also another jpg describing the multiplexing chart. Let me know if you have figured out the same?
Posted by diyjesus on June 20, 2009 at 09:12:44 Pacific Time

Alesis SR 16
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Thanks. I will give it a go soon and get back with you...

Ian

Posted by r05c03 on March 16, 2009 at 08:28:24 Pacific Time

Alesis SR 16
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I haven't opened up an Alesis but I know it has rubber switches which push onto a circuit board. Carefully open the box and find the traces where the black rubber contact of the switch touches the circuit board. It should look like two sets of traces (lines). To test that you have the correct points, with the drum plugged in touch the two lines together with a bare wire. You should hear the drum sound for that button. Do this for all the buttons. Then turn off the power and solder a pair wires to each set of traces. Each pair of wires goest to a switch in the 4066 chip.

The 4066 has four switches. Each 4066 switch replaces the function of the rubber button.

Write again if you have any problem.
Posted by Tzim on March 10, 2009 at 12:53:23 Pacific Time

Alesis SR 16
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Hi guys, I have been working on Alesis-SR16 to convert it into a midi drum controller using external triggers. This article has ofcourse helped me a lot. SR-16 differs slightly from the zoom machine as it doesnt senses a switch grounded in order to trigger. Instead it works on a matrix principle quite similar to keyboards. the 12 pads are actually connected to a 6x2 matrix using flipflops if you know what i mean. I have built circuit using 2x4066 to just control 8 of the pads. If anyone has come that far i have a few questions;
1-When i add caps and resistors as shown in these schematics, the piezos do not activate 4066 switches at all so i have left them out.
2-There is a bit of latency between hitting the piezo and the sound coming out. Theres no latency in the actual drum machine itself when you use the onboard pads. Surely a 4066 switch wont be introducing that particularly as there is no cap in there. Did you experience any latency with zoom?
If anyone has worked on SR-16 please let me know how you got on.

Posted by diyjesus on June 18, 2009 at 03:32:35 Pacific Time

Alesis SR 16
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schemtis & souce code,thank you!
Posted by phapple on February 07, 2010 at 11:53:50 Pacific Time

Alesis SR 16
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Hi
Don't know if anywone can help me but I have an Alesis SR16 that has a burnt out capacitor (C5)on the power input.
Can anyone tell me what its value is..it is so fried it is unreadable.
I know this is a bit off the topic but if someone had their SR16 open they might be able to read the value.
cheers and thanks
rooeq
Posted by rooeq on June 20, 2009 at 19:37:30 Pacific Time

Alesis SR 16
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Hi Rooeq,
If its the bottom one of the 3 big blue caps at the power input then its 1000uf 16v. on mine its called C57 for somereason. its under C2 & C3.
BTW while playing around with the sr-16 my LCD screen fell off :p. yes it just 'fell off'. seems like it was just resting on the contacts. has anyone had that before. having trouble trying to place it back on to work.
Posted by diyjesus on June 22, 2009 at 03:53:32 Pacific Time

Alesis SR 16
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The resistor and capacitor are to stretch out the pulse from the string/aluminum tape switch so the drum machine scanner will see the switch closure.

Sounds like you replaced the switch with the piezo and you are relying on the voltage generated by the piezo to turn on the 4066 CMOS switch.

You really need some signal conditioning on the piezo signal before applying it to the 4066 because the piezo signal may be too small or large, will not discharge fast enough, or be too long or short of a pulse.

So put a resistor across the piezo to discharge it, and apply the signal to a comparator, then put the output of the comparator to the 4066. I assume the pulse will be too short, as it was for the ZOOM drum machine, so you can use the R C circuit I used between the comparator output and 4066 control line input. [A schematic would be a lot simpler than all these words.]

-Tom
Posted by Teazer on June 18, 2009 at 07:58:17 Pacific Time

This seems like such a cool idea!
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I'd absolutely LOVE to make one of these. The only problem? There's no instructions short of some basic circuit designs. Maybe I'm missing something here, but instructions usually include more than a diagram that not only presupposes you have a robust understanding of electrical engineering, but also that, in looking at these circuit designs, you will automatically understand the materials needed and how they are assembled. This is not the first project I've seen on Make of this nature.

Please Make, can you start actually giving us some idea of how to make stuff? All I've found here is a tantalizing illustration of my lack of electrical understanding. If I need to go to Radio Shack and get a Circuitry for Dummies book, so be it, but can you at least give me some idea of what I'm supposed to learn? I'm a software engineer of 13 years and I have no idea what to make of these.

Or is this simply a "if you buy the magazine we explain in detail" teaser? I'll BUY the stupid thing if it actually offers step-by-steps!
Posted by Zen_Kai on October 31, 2008 at 10:21:33 Pacific Time

This seems like such a cool idea!
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I'm glad you like the idea. The magazine has a limited amount of space so it's hard to teach basic electric wiring, soldering and schematic reading. But your point is a good one. Here is a great video on soldering technique http://www.youtube.com/watch?v=I_NU2ruzyc4&feature;=related
Posted by Teazer on December 09, 2008 at 13:53:22 Pacific Time

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