From: tod@nntp-server.caltech.edu (Tod Edward Kurt) Subject: Homemade Piezo drum triggers / MIDI percussion controller Date: 26 Jul 91 23:16:39 GMT Hello All, I'm building me a little box (using the MC68HC11 microcontroller) that takes percussion hits and translates them to MIDI messages --basically, building myself an Octapad sort of a thing. I've got everything worked out, except the actual triggers themselves. I'm going to use practice pads with peizo elements mounted on them, but I was wondering if anyone has done this already, and has suggestions/schematics/ ideas they would like to share with me. The A/D inputs of the controller need to be from 0-5v. What are good (cheap) piezo elements to use? What kind of reverse voltage / overvoltage protection should I use? (a few diodes I imagine) Where is a good place to get the piezo's cheap? Any help would be appreciated. Oh, and if any one is interested, the toy has these features: -- 8 drum inputs, featuring full 0-127 velocity resolution -- up to 8 on/off footpedal inputs that might: - modify results of the drum inputs (eg. for open/closed hihat) - change mappings - send program change commands, etc. -- 16 char x 2 line LCD display showing MIDI chan / note num that're transmitted -- fully mappable / saveable presets for different drum setups -- small (1 RU, or perhaps belt-clippable) -- battery powered (with a long operating time) -- low chip count ( 1 chip, the microcontroller) So, besides the peizo queistions, what else would you MIDI-people like in such a device? I'm making this for me, but if others like it, cool. I think the project will be simple enough that, if all goes well with the prototype, I might try to publish it in Electronic Musician (if they would stop being so shallow and publish construction articles again) -Tod E. Kurt tod@yvonne.caltech.edu -or-- tod@moriarty.caltech.edu From: Mike.Rivers@f440.n109.z1.FidoNet.Org (Mike Rivers) Subject: Homemade Piezo drum triggers / MIDI percussion controller Date: 2 Aug 91 03:07:50 GMT I've read messages on BBS's from people who have made similar triggers using piezo transducers from Radio Shack. They attach them directly to the pads with glue or double-sticky tape. They're sold to work as beepers, but work fine the other way. The stock numbers for the three sizes are: 273-091 273-073 273-064 Price is between $1.50 and $2.50, depending on the size. The smaller ones come in a plastic case which you'll probably have to remove. Get a couple of each and experiment to see which one works best. * Origin: ENIAC * read John 3 * 301/460-9134 == (1:109/440.0) From: news@pacvax.UUCP (USENET News System) Subject: Re: Midi drum triggers Date: 20 Nov 91 14:49:16 GMT I recently came upon some instructions & am about to make some MIDI drum pads of my own. I've told that all one needs is a $1.50 piezo ceramic transducer from Radio Shack. Mount it on a piece of plywood, cover with a rubber mat, and feed the transducer output into a MIDI drum kit "brain" like a Simmons SDS-9. You may need to put a 100k Ohm pot on the line to trim the voltage spike. I haven't tried any of this yet, If anyone has done it before, or has any advice I'd love to hear it. If people are interested, I can post the results of my experiment. Dave Fagan Pacer Software, Inc. daf@pacvax.uunet.uu.net From: system@cyberden.uucp (Xorcist) Subject: Re: Building Drum Triggers Date: 18 Dec 91 23:30:44 GMT I once was going to do this... my advice... just buy some old Simmons trigger pads. The black octagon types with 1/4" plug outputs... by the time you spend all your time and money making a trigger, you'll be sorry. As a used simmons pad of this type goes for about $25, you should be able to do a lot better this way. Also, those pads can really take a beating. Other then that, use Radio Shack piezo speaker elements and silicon them to the back of some relatively thin plywood. (a simmons pad). I took a radio shack plastic drum set (their 'top o' the line' plastic nightmare set), and spliced the outputs into a yamaha DD-5 drum machine. It worked great! Only problem was that the pads were cheap and they started getting on my nerves... so I bought 4 XLR type simmons pads and a stand for around $150. Now I just need to get a trigger to midi converter ala PM-16 as the DD-5 only has 4 inputs and I'm going to need more for other drums on the stage... _____________________________________415_472_5527__ | / |\ | H E \ Y B E R |/ E N system@cyberden.uucp (Xorcist) From: mxmora@unix.sri.com (Matthew Xavier Mora) Subject: Re: MIDI drum kit questions Date: 15 Jan 92 19:31:05 GMT I made my own triggers using Radio Shack Part Number 273-091. This is a Peizo Speaker. Just connect a cord to the two leads with a phone jack on the other end and plug it into the D4. Works like a charm. Gelb music has a Gilbralter Drum practice pad set for $210.00. I 'm going to get the set and slip the triggers under the rubber pads. It comes with 4 pads and one for the kick pedal. ---------------------------------------------------------------------------- |Matthew Mora Matt_Mora@QM.sri.com | |SRI International mxmora@unix.sri.com | ---------------------------------------------------------------------------- From: glen@tegra.COM (Glen Osterhout) Subject: Re: MIDI drum kit questions Date: 16 Jan 92 22:18:09 GMT I tried to do exactly the same thing you are suggesting. It isn't quite that simple though: if you put the piezo elements directly under the thick rubber pads of the Gibralter you will find that you have a very small useful area of drum pad to work with. If you hit the pad even an inch or so away from where the piezo element is positioned, the trigger intensity is much lower than if you hit directly over it. The probable solution (which I haven't acually tried yet!) is to put a disk of some stiff-but-light material under the rubber pad and mount the trigger under that. You should also put a layer of springy foam (antistatic foam works well for this) between the steel mounting plate and the piezo element so the element can vibrate more freely. By the way, you should first remove the Radio Shack piezo element from the plastic case it comes in. Unfortunately, all those layers are too thick too allow the rubber pads to be fit back onto the steel plate; black duct tape can be used to hold thing together but maybe someone can suggest a more esthetically acceptable solution. Original Gibralter practice pad assembly: Rubber-> |||||||||||||||||||||||||||||||||||||||||||||||||||||||| |||||||||||||||||||||||||||||||||||||||||||||||||||||||| Steel plate-> ======================================================== ( ) / / / / / / / / / / / / Modified assembly: Rubber-> |||||||||||||||||||||||||||||||||||||||||||||||||||||||| |||||||||||||||||||||||||||||||||||||||||||||||||||||||| Stiff disk-> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Piezo element-> ~~~~~~~~ Springy foam-> ******************************************************** Steel plate-> ======================================================== ( ) / / / / / / / / / / / / /*++************************************************************************** * Glen Osterhout Tegra-Varityper, Inc. Billerica, Massachusetts * email to: glen@tegra.com **--*************************************************************************/ From daver!mips!dale!alighton@Sun.COM Fri Jan 17 13:06:37 1992 To: fins@dosnfs-pc.Corp.Sun.COM Subject: Re: MIDI drum kit questions I have a roland Octapad and wanted to build some triggers for the extra inputs. I bought the radio shack piezo buzzers and built some pads that have worked real well. I'm sure they would work equally well with the D4. For the Toms and snare, I bought Remo practice pads. They are made of gray plastic, have a regular drum head on them and a pseudo tensioning ring. They are about 2" thick and are filled with soft foam rubber. I mounted the peizo buzzer to the underside of a .06 thick circular aluminum plate with a slightly smaller diameter than the inside of the practice pad, and then cut away most of the foam rubber in the drum pad so that the plate rests on a foam shelf around its perimeter. The foam looks like a foam ring, with a cross section like this: ______________________________________________________ | |____________________________________________| | | | | | | | | | -------------------------------------------------------- With the aluminum plate cradled in the foam ring, there is very little chance that hits on adjacent pads can trigger the sensor. I then fill the gap between the plate and the underside of the drum head with a sheet of foam rubber (I used the pads that are for muting drums, wet suit material would work GREAT, so would your basic mouse pad). Drill a hole for the cable to come out, assemble the whole thing, and it works GREAT and doesn't look bad either. They sell these pads in 6", 8", and 10" diameters. They come with a mount on the underside, so they are easy to mount. The stick response is very much like a real drum, and is a little adjustable for your liking. Total cost to build one is between 27 and 35 dollars, depending which diameter pad you buy. For Cymbals, I used Dog frisbees (made of rawhide)! I tried plastic frisbees but they don't hold up. I mounted one of the sensors to the underside of the frisbee using silicone rubber (use the stuff made for electronics, the other has acetic acid that will destroy electronics!!) , even used the housing the buzzer came in to secure it there. They look kind of silly but work GREAT!!!! Total cost per cymbal is less than $10.00. For the bass drum, I bought a regular pedal, but made it so the beater was beating down against a horizontal surface instead of against a vertical surface. I encapsulated a peizo buzzer in a rubber/steel motor mount from somekind of car, and made a wood block to hold it where the beater on the pedal can hit it. Total cost was about 80 bucks including the Premier bass drum pedal. Any kind of bass drum pedal will work as long as the beater attaches to the pivot shaft with a separate clamp from the chain or belt that drives the shaft from the pedal. If it has an integral clamp for both the beater and the drive attachment, it means you have to find a way to hold the sensor vertically in front of the beater like a bass drum head, making matters far more complicated. I built a space frame to hold all this shit out of PVC irrigation tubing (use schedule 40, 1inch or larger). The entire frame cost less than 35 buck, and uses hose clamps and mounts made from PVC elbows with epoxied in bolts to hold the drum pads/cymbals. I admit, it sounds hokey. But the whole thing works great and was WAY cheaper than buying all this stuff. It seems to be taking the beating and holding up just fine. Al Lighton Titan Linkabit From: supplies@sklib.usask.ca Subject: RE: Homemade Drum Pads... Date: 26 Mar 92 16:08:57 GMT Try using a piece of styrofoam packing (from some small piece of gear) then lay your transducer in it. then cut a piece of plywood to fit inside the foam and over top of the transducer. I fit two inside one piece of foam and it works great. I have transducers on all my drums but I wanted a few extra triggers. It does what I need, It doesn't look slick but since it sits on top of my bass drum behind my toms, nobody sees it and it works well. I'm using the Alesis D4 module. The analog trigger inputs are great. From: JSIMON@TRINITY.EDU (Jonathon Simon) Subject: Re: Homemade Drum Pads... First, if you are paying 90-150 bucks for a drum pad that's too much. LP Spikes and Duaz are very good pads that list for $89 - you should be able to pick them up for about $55 mail order (or at your local music store with a little bargaining) - drums are generally discounted a little more than synths and guitars. Some snare pads which have a seperate rim sensing feature cost more. I don't like what I've seen from Roland in the past, although the may recently have come up with something I haven't seen. If its between Roland and making your own, I'd say - do it - and save. Secondly, if your trying to achieve the sensitivity and dynamics of real drums, piezos don't cut it. On the other hand, if all you want is a kick on 1 & 3, snare on 2 and 4, dance/pop kind of thing, piezos taped to a 10 dollar practice pad might do just fine. Piezos are 2nd generation pad technology (1st generation pads only did on/off triggering - at least piezos can sense dynamics, although, not as well as the newer pads). The newest (3rd) generation of pads are made of a force sensing material. This force sensitive material not only gives the dynamic soft to hard response of a well tweeked piezo activated pad, it also can transmit a sustain signal for the length of time the stick maintains contact with the pad. You no longer have a variable voltage on/off trigger. Now you have control over the duration of the note. With most percussion sounds, note durations are over in less than a second, but the ability to alter that duration by a 1/4 or 1/8 a second (assuming your keyboard or drum brain can deal with percussion this way) gives the drum part more real sounding quality. From: "Kevan L. Moore" Newsgroups: rec.music.makers.synth Subject: HOW TO BUILD TRIGGERS for ALESIS D4 Date: 15 Jun 1995 19:19:32 GMT I'm sure these triggers could also be used for anything that could convert analog voltage (pulses) to midi. PAiA sells a little brain kit that does exactly that. But the D4 already has 12 trigger inputs (i know) and can re-route them to any midi number, (i'm guessing). I hope the author of this will forgive me for posting this but he posted it to an open group, so i assume he's ok with it. i've sent this to a few people on a few lists. i appreciate his work and hope that many people will benefit from his pioneering design. How to Make Triggers for the D4 Drum Machine ============================================ By Mike Dalton (miked@plaza.ds.adp.com) FIrst, there is no *one* correct method to do this. I will describe the general method I used and then you can try this along with *your* own variations. The following information will allow you to make very inexpensive drum pads that play nicely, and can be used as input triggers to an Alesis D4 drum sounds rack module. THe key here is very simple. If you want to get the essential info and start playin' around with this idea. then do the following: ---------------------------------------------------- Part 1: The down and dirty "proof of concept" 1. Go to Radio Shack and buy 1 or more Piezo buzzers. Note that there are *many* to choose from. THe one that I use is the one that costs $1.49 each (as of 10/94). THey are about the size of a U.S. quarter (you know, 25 cents..quarter) and they have two (not three) wires, a red and a black one. They are also enclosed in a black (incredibly rugged) plastic case. Buy two or three of these to experiment with. 2. Select one of these to be your first experiment-ee. Remove the plastic case. *HOW* you remove the plastic case is up to you. It can be a real pain. *REMEMBER* you do *NOT* want to damage or bend the side of the black plactic case without the hole. The side *with* the hole can literally be broken off a bit at a time by the following: hold the whole thing firmly and taking a small pair of needle nose pliers, bend the plastic case by grabbing around the small whole. Eventually you'll break enough away to allow you to see into the little black case. THat brass-colored flat thing in the bottom is the buzzer. Continure breaking the case away until all you have left is the flat brass colored buzzer with its wires attached to the white-colored backside. Note. If in the process of extracting the little buzzer from the black case you pull a wire off, simply resolder it. 3. Now remember, this is the "down and dirty" set of instructions, so... Attach a 1/4" phone plug to this thing, with the red lead to the "tip" and the black wire to the "ring" on the 1/4" plug. (Note: you'd probably be well advised to lengthen the wires a bit first) 4. Plug the whole dangling affair in to a D4 trigger jack and follow the D4's trigger set-up instructions. 5. Tap the small little brass-colored side of the plugged-into-the-D4 buzzer, and lo and behold, DRUM SOUNDS! Okay, enough, now you have proven your inventivness,maybe you are not Thomas A. Edison but the "thrill of it all" has happened. OBVIOUSLY this will work, but even more OBVIOUSLY you still need to build a drum pad assembly into which you will bury this wonderful trigger 'thang'. SO, the next set of instructions will describe what *I* have done thus far. You will *most likely* come up with a better "recipe" (please email it to me so *I* can benefit too!). Part 2: How I made *my* triggers -------------------------------- I went to several local hardware and plumbing supply houses and picked up a bunch of C_H_E_A_P stuff. My theory was that something small and round a few inches deep and wide has probably already been manufactured. I picked up a 5" endcap and a 5" knock out plate for (you guessed it) 5" sewer pipes. Then I did this: ___________________________________________ |___________________________________________| <- 5" circular cut from linoleum <@@@@@@layer of silicon caulking@@@@@@@> --------------------------------- <- 4" circular thin metal disc <@@@@@@layer of 5 minute epoxy @@@@@@> ########### <- piezo buzzer w/out case | | | | ==\ <%%%%layer of thin foam rubber%%%%> /== ===\____________________________________/=== <- 5" Knock-out plate | | | | | | || | | || || | | || || | | || || | ----(black)------------- || --(red)--------__/\________ <- RCA Jack || || ||========================================|| ^ | 5" diameter sewer PVC endcap "Dalton's Drum Trigger Cross Section" I experimented with differant things in the areas of glues to hold all the pieces, and silicon, hard rubber, soft rubbers, foam rubber, etc. in the above "recipe". Differant things gave differant bounce and velocity curves. Once I had a recipe that worked for my needs, I Epoxy-glued several of these triggers to drummers "cage" constructed from 1.25" PVC plumbing pipe and glued with PVC glue. I followed the D4 Manuals instructions for the elemination of false triggering and mounted a piezo buzzer/trigger to the "cage" itself and fed it into the D4. This procedure to eleminate false triggering along with the manuals recommended adjustments to each pad completely eleminated false triggering. This was a bit of fun to do. Now I can lay down a "boom-chop" rhythm trak to work the rest ofa song out to, and when its finished I can go back, erase the referance track, and lay down the whole drum kit "live-playing" with these triggers. Cooool! Lastly, I bought a Remo practice pad and put a trigger-epoxied-to- a-thin-metal-plate (as shown above) in a slit made in the middle of the foam under the head (take apart a Remo practice pad & you'll "get it". I mounted a jack, wired the trigger, and viola! I have a separate snare trigger in addition to the cage. Closing Thoughts: This was actually a great project. I think the Remo idea is as good as any, but home-made triggers open up alot of inexpensive options to the MIDI-fied musician. I realized that these little buzzer things are sensitive enough to play with your fingertips. You guessed it. My next project is to build a complete trigger-pad-set that is "finger playable" Your mileage may vary...enjoy! --------------------- (end of mike dalton's post)----- keep in mind: all this does is make an analog pulse. you need an intelligent unit of some sort (paia kit or alesis D4) to convert this analog pulse to midi. if anyone has any success with this, please let me know. i've been meaning to try this for months but have been getting everything EXCEPT a d4. thanks again to mike dalton for his design and his willingness to share it with the original list. kevan l moore ************************************************ DRUM TRIGGER PAD ASSEMBLIES (VARIOUS TECHNIQUES) ************************************************ From: jgreen@bogey.pd (John Green) Date: 31 Oct 1994 19:38:32 GMT This is a description of my experience constructing a drum trigger following instructions I got from some kind people here. 1. Went to Radio Shack and bought 2 piezo speaker elements ($1.99 each). 2. Connected the two wires to a 1/4 inch cable. 3. Plugged the cable into my D4. 4. Placed a mouse pad on the piezo. It worked perfectly. I could play any of the 500 sounds, send MIDI data out from the D4 and record it. No adjustment of the Trigger attributes on the D4 required. Velocity sensitive. Now I'm going to build a Octa-Pad of sorts with 8 of these mounted on a board, somehow isolated from each other. I'm also going to experiment with different thicknesses of pad, etc. Mail if you want more info. ------------------------------------------------------------------------------ Note: the remaining entries on this page were collected together in an archive and appear to have been garbled at some point. I've tried to reconstruct it from two separate sources. Apologies for any remaining glitches. If anyone has a copy of this material intact, please let me know. ------------------------------------------------------------------------------ From: alighton@dale.cts.com Date: Wed Aug 12 08:47:11 1992 I have a roland Octapad and wanted to build some triggers for the extra inputs. I bought the radio shack piezo buzzers and built some pads that have worked real well. I'm sure they would work equally well with the D4. For the Toms and snare, I bought Remo practice pads. They are made of grayplastic, have a regular drum head on them and a pseudo tensioning ring. They are about 2" thick and are filled with soft foam rubber. I mounted the piezo buzzer to the underside of a .06 thick circular aluminum plate with a slightly smaller diameter than the inside of the practice pad, and then cut away most ofthe foam rubber in the drum pad so that the plate rests on a foam shelf around its perimeter. The foam looks like a foam ring, with a cross section like this: ~Sorry Diagram Missing!~ With the aluminum plate cradled in the foam ring, there is very little chance that hits on adjacent pads can trigger the sensor. I then fill the gap between the plate and the underside of the drum head with a sheet of foam rubber (I used the pads that are for muting drums, wet suit material would work GREAT, so would your basic mouse pad). Drill a hole for the cable to come out, assemble the whole thing, and it works GREAT and doesn't look bad either. They sell these pads in 6", 8", and 10" diameters. They come with a mount on the underside, so they are easy to mount. The stick response is very much like a real drum, and is a little adjustable for your liking. Total cost to build one is between 27 and 35 dollars, depending which diameter pad you buy. For Cymbals, I used Dog frisbees (made of rawhide)! I tried plastic frisbees but they don't hold up. I mounted one of the sensors to the underside of the frisbee using silicone rubber (use the stuff made for electronics, the other has acetic acid that will destroy electronics). For the bass drum, I bought a regular pedal, but made it so the beater was beating down against a horizontal surface instead of against a vertical surface. I encapsulated a piezo buzzer in a rubber/steel motor mount from some kind of car, and made a wood block to hold it where the beater on the pedal can hit it. Total cost was about 80 bucks including the Premier bass drum pedal. Any kind of bass drum pedal will work as long as the beater attaches to the pivot shaft with a separate clamp from the chain or belt that drives the shaft from the pedal. If it has an integral clamp for both the beater and the drive attachment, it means you have to find a way to hold the sensor vertically in front of the beater like a bass drum head, making matters far more complicated. I built a space frame to hold all this shit out of PVC irrigation tubing (use schedule 40, 1inch or larger). The entire frame cost less than 35 bucks, and uses hose clamps and mounts made from PVC elbows with epoxied in bolts to hold the drum pads/cymbals. I admit, it sounds hokey. But the whole thing works great and was WAY cheaper than buying all this stuff. It seems to be taking the beating and holding up just fine. here is some more: I am using an Octapad I, not the later units. There is all kinds of sensitivity adjustments, they generally need to be set fairly sensitive. The key to no false triggering from adjacent hits is mechanical isolation. Thas why the metal plate is suspended in a foam cradle. The key to increasing the sensitivity of the piezo thing is to have it in intimate contact with a larger metal plate. The metal plate will conduct vibrations from a considerable distance to the crystal. You ARE removing the piezo thing from the housing, aren't you? You HAVE to atleast remove the bottom cover of the housing (which is the back side of thelittle circuit card, DON'T break it!!) and flip the sensor upside down in the housing, and pot it flush with 5 minute epoxy. You MUST have vibration thru a solid medium transmitted directly to the little brass plate that the sensor is mounted on, and the more "solid" the medium is the better. For instance, 5 minute epoxy works better than 24 hour epoxy becuase it is more brittle and has a lower damping constant. Except for on the "cymbals" (dog frisbees), I always remove the entire piezo assy from the black plastic housing and glue the wholeshabang to an aluminum plate. WAY increases the sensivity. The way false triggering from adjacent pads is achieved inside the octapad is thru some active sensing circuitry. A couple extra piezo sensors are attachedto the metal frame of the octapad. When you hit a pad, it only transmits the difference signals between the hit pad and the frame sensors. I guess that assumes that vibrations on an adjacent pad and the fram would be approximately the same, so no signal would be transmitted from the adjacent pad. But the hit pad would have a way larger amplitude hit, so a trigger would occur. The Alesis D4 actually has variable parameters for controlling the sensitivities of the difference signals. If you are using a bass drum pedal, take a toilet paper tube, cut it in half so it is only about 2 inches long or so. Tape up the bottom hole. Attach more rugged wires to the very fine leads on the piezo buzzer. Fill the tupe halfway with epoxy. Drop in the sensor, make sure the wire joint is down in the tube somewhat. Continue filling the tube almost to the top. 5 minute epoxy willprobably be too exothermic for this, you better use 30 minute epoxy. Let the whole thing cure. Build a block of wood that will hold this tube of epoxy. I suggest wiring a 1/4" phono jack and mounting it to the piece of wood. I used a Stratocaster jack plate for this. Design the block of wood so that the bass drum clamp can clamp on to the piece of wood in such a position that the bass drum beater will beat on the end of the tube of epoxy. This will be easier if you have a bass drum pedal that allows the beater to be rotated on the pivot shaft relative to the pedal, so that the pedal is not beating against a vertical bass drum. Al Lighton ------------------------------------------------------------------------------ From: js0998%future@uunet.UU.NET (Cam Spillman) Date: Fri Aug 14 11:05:44 1992 I built mine using quarter-sized flat piezo buzzers. I made a trigger pad substrate of 1/4" particle board, then put a layer of closed-cell foam (like mouse pads or wetsuit mat'l) about 1/4" thick, then rubber strike-surface I got from a friend who works in a belt-rubber factory, about 1/4" thick also. I made a hole in the closed-cell layer as big as the trigger and mounted it with rubber cement about halfway in. These seem to work well, and false-triggering is kept to a minimum by isolating the piezo from both the strike surface and the base surface. So if I hit other pads on the stand it doesn't propagate vibrations thru to the other units, and when I hit the strike surface I have some dampening in the foam layer to keep it from overloading. This may not be the only way to do it, but it was the way that worked given information I got from Electronic Musician mag, circa 1989 (?) and the materials I had on hand. For what it's worth, I made a really funky hi-hat assembly with one pad mounted on a hi-hat stand, one pad sandwiched between foam underneath the pedal. The top pad is *open* and the bottom trigger is *close*. Oddly enough, it seems to work OK and doesn't overly offend my drummer friends (they are a little shocked but appreciate the insipid simplicity of the design). Good Luck! Cam ------------------------------------------------------------------------------ And now for some of my own experiences: I used several different kinds of buzzers. The best ones were model number 23-073. Cheap ($1.49) and simple to break out of the plastic case. Avoid all three wire piezos. The third wire is connected to a separte element, which is used to provide a feedback signal for your basic oscillator/speaker circuit. This third element was definately the cause of the false triggers in my origional setup - using two wire piezos cured the problem. I glued the triggers to aluminum plates (found in the trash) using epoxy - this trick really improved the signal level and overall response (thanx Al!). For a bass drum, I made a right angle out of wood and purchased a bass drum pedal (39$, used) I covered the metal plate with some foam, put some softer foam behind it and screwed it to the wood. The original wood piece was too resonant and caused some false triggers, so I nailed a second piece of wood to the back of the first, which increased the mass enough to stop the vibrations. The other triggers are currently resting on top of blocks of foam on a table. Next step is to build a PVC rig to hold them. I need better stuff for the impact surfaces, as the foam I have is not bouncy enough, but I have located a big warehouse distributor, and I'm sure it will be no problem. So I now have a 12-note Octapad instead of an 8-note. Makes life much happier. hope this helps. cliffw ------------------------------------------------------------------------------ From negatvnein@aol.com Tue Dec 19 10:28:10 1995 From: negatvnein@aol.com (NegatvNein) Subject: Re: Drum Triggers for Sound Module? Newsgroups: rec.music.makers.synth Date: 15 Dec 1995 22:05:30 -0500 Organization: America Online, Inc. (1-800-827-6364) Reply-To: negatvnein@aol.com (NegatvNein) Path: cs.ruu.nl!sun4nl!EU.net!newsfeed.internetmci.com!howland.reston.ans.net!news-e1a.megaweb.com!newstf01.news.aol.com!newsbf02.news.aol.com!not-for-mail Lines: 7 Sender: root@newsbf02.news.aol.com Message-ID: <4atd1q$644@newsbf02.news.aol.com> References: <30D05600.102F11D5@compulink.co.uk> NNTP-Posting-Host: newsbf02.mail.aol.com PAiA makes a kit for a force to CV trigger pad that is to be used with midi, it only costs about $30 per module, and PAiA has a midi control card that can take up to 8 velocity sensitive inputs, that is only $80, quite a good deal, i use them with old drumming practice pads, they look very professional, those i believe are fairly inexpensive, you simply unscrew the top ring, place the trigger under the head, or under the foam under the head with the cable running out, and replace it, it works very well