17 Oct
2008
17 Oct
'08
12:49 p.m.
Sorry for the very random subject, but I figured I'd need all the help I can
get.
I've read about this for a _little_ while (time constraints..arghhh) on the
WWW, and I've posted on www.edrum.info too. In case anyone here has
better/fast/helpful suggestions/advice/shizznit, I'm sort of cross-posting:
I just want one trigger, which I'll use for the kick drum. As such, I'm
interested to know if there are premade boards for the MIDI conversion.
Basically all I need is something which can take the vibrations and convert
them to electrical signals (piezo), and then fed to something else that will
convert that electrical signal to a MIDI-ON message, after which I can plug
it into the MIDI input of an audio interface or use a MIDI-USB adapter to
plug in to a USB port.
And regarding MIDI, if I want to take into consideration dynamics, and let
the piezo trigger MIDI messages with varying attack information, how would
it be done? So depending on the voltage generated, it'd be a MIDI-ON but the
final message to the computer (audio interface) would be a "MIDI-ON &&
ATTACK == 75" sort of logic. Sorry for the noobish description, have just
started to dabble into (audio/midi) electronics.
I understand the concept and design roughly and I can move on by reading the
construction manual (refering to edrum's DIY guide), but at the moment I'm
looking for a quick way to build a trigger as I need it asap (and no $$ for
a real trigger kit/module).
17 Oct
17 Oct
1:09 p.m.
New subject: [LAD] [OT] DIY Trigger - Piezo to MIDI to PC
"Ray Rashif" <schivmeister(a)gmail.com> writes:
And regarding MIDI, if I want to take into
consideration dynamics, and let
the piezo trigger MIDI messages with varying attack information, how would
it be done? So depending on the voltage generated, it'd be a MIDI-ON but the
final message to the computer (audio interface) would be a "MIDI-ON &&
ATTACK == 75" sort of logic. Sorry for the noobish description, have just
started to dabble into (audio/midi) electronics.
I know a way to implement this. I've read it somewhere in
Internet. piezo output is limited using zener diode (you want to do this
anyway because next electronic components may get burned out). Then you
can measure width of the impuse. Wider the impulse is, more "attack" you
have. In midi terms drum attack becomes midi note on velocity parameter.
I understand the concept and design roughly and I can move on by reading the
construction manual (refering to edrum's DIY guide), but at the moment I'm
looking for a quick way to build a trigger as I need it asap (and no $$ for
a real trigger kit/module).
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Nedko Arnaudov <GnuPG KeyID: DE1716B0>
4:29 p.m.
New subject: [LAD] [OT] DIY Trigger - Piezo to MIDI to PC
Oh wow, every single one of you starting from Nedko have just saved me hours
of research! Thanks so much guys, extra points to Andy for his walkthrough
with bonus code, Folderol for citing the exact reference material and Josh
for landing the correct device (eroktronix) =P
Yes, it's obvious yet I didn't contemplate the piezo-DI-soundcard route. I
feel so stupid now, but thanks to the prompt response here I have something
to work on right away. Initially, and also the reason why I was so lost with
this is because, I wanted to bypass a full-fledged microcontroller eg.
Arduino (since I'm only dealing with one channel) but still have MIDI via a
very simple breadboard _before_ reaching the computer. Credit this to my
lack of understanding.
Yes, I'm sticking the piezo onto the skin/head internally. As for the beater
hitting directly, I don't know if that's harmful but it's worth a try.
I'm
positioning it behind the skin opposing the surface area where the beater
hits, instead of placing it "off-axis" somewhere else nearer to the rim
(common when triggering externally). In any case, I've got to get the signal
up and running before I can actually toy around.
I like the threshold-detector-software suggestion, but as mentioned, it'll
be a safer bet going with Arduino as most of the electronics are taken care
of.
This list is awesome.
5:40 p.m.
New subject: [LAD] [OT] DIY Trigger - Piezo to MIDI to PC
Ray Rashif wrote:
Oh wow, every single one of you starting from Nedko
have just saved me
hours of research! Thanks so much guys, extra points to Andy for his
walkthrough with bonus code, Folderol for citing the exact reference
material and Josh for landing the correct device (eroktronix) =P
Glad what I posted
what helpful.
I actually posted the wrong C code - the right files are attached to
this email.
Would be good to know how you get on with this as I'm thinking of making
a midi'ed bass drum beater at some point.
andy
device="/dev/ttyUSB0";
mapping="Tom Toms";
pads=4;
kits: (
{ name="GM Kit";
sounds=(
(35,"Acoustic Bass Drum"),
(36,"Bass Drum 1"),
(37,"Side Stick"),
(38,"Acoustic Snare"),
(39,"Hand Clap"),
(40,"Electric Snare"),
(41,"Low Floor Tom"),
(42,"Closed Hi-Hat"),
(43,"High Floor Tom"),
(44,"Pedal Hi-Hat"),
(45,"Low Tom"),
(46,"Open Hi-Hat"),
(47,"Low-Mid Tom"),
(48,"Hi-Mid Tom"),
(49,"Crash Cymbal 1"),
(50,"High Tom"),
(51,"Ride Cymbal 1"),
(52,"Chinese Cymbal"),
(53,"Ride Bell"),
(54,"Tambourine"),
(55,"Splash Cymbal"),
(56,"Cowbell"),
(57,"Crash Cymbal 2"),
(58,"Vibraslap"),
(59,"Ride Cymbal 2"),
(60,"Hi Bongo"),
(61,"Low Bongo"),
(62,"Mute Hi Conga"),
(63,"Open Hi Conga"),
(64,"Low Conga"),
(65,"High Timbale"),
(66,"Low Timbale"),
(67,"High Agogo"),
(68,"Low Agogo"),
(69,"Cabasa"),
(70,"Maracas"),
(71,"Short Whistle"),
(72,"Long Whistle"),
(73,"Short Guiro"),
(74,"Long Guiro"),
(75,"Claves"),
(76,"Hi Wood Block"),
(77,"Low Wood Block"),
(78,"Mute Cuica"),
(79,"Open Cuica"),
(80,"Mute Triangle"),
(81,"Open Triangle")
);
},
{
name="A Minor Pentatonic";
sounds=(
(45,"A2"),
(48,"C3"),
(50,"D3"),
(52,"E3"),
(55,"G3"),
(57,"A3")
);
}
);
channels: (
{ name="GM Kit 1"; kit="GM Kit"; midichannel=10; },
{ name="A Minor Pent 1"; kit="A Minor Pentatonic"; midichannel=1;}
);
mappings: (
{ name="Tom Toms";
hotkey="t";
pads: (
{pad=0; channel="GM Kit 1"; sound="Low Floor Tom"; },
{pad=1; channel="GM Kit 1"; sound="Low Tom";},
{pad=2; channel="GM Kit 1"; sound="Low-Mid Tom";},
{pad=3; channel="GM Kit 1"; sound="High Tom";}
); },
{ name="Congas and claves";
hotkey="c";
pads: (
{ pad=0; channel="GM Kit 1"; sound="Low Conga"; },
{ pad=1; channel="GM Kit 1"; sound="Open Hi Conga"; },
{ pad=2; channel="GM Kit 1"; sound="Mute Hi Conga"; },
{ pad=3; channel="GM Kit 1"; sound="Claves"; }
); },
{ name="Acoustic Kit";
hotkey="a";
pads: (
{pad=0; channel="GM Kit 1"; sound="Acoustic Bass Drum"; },
{pad=1; channel="GM Kit 1"; sound="Acoustic Snare"; },
{pad=2; channel="GM Kit 1"; sound="Closed Hi-Hat"; },
{pad=3; channel="GM Kit 1"; sound="Pedal Hi-Hat"; }
); },
{ name="Bass, Bongo and Maracas";
hotkey="b";
pads: (
{pad=0; channel="GM Kit 1"; sound="Bass Drum 1"; },
{pad=1; channel="GM Kit 1"; sound="Low Bongo"; },
{pad=2; channel="GM Kit 1"; sound="Hi Bongo"; },
{pad=3; channel="GM Kit 1"; sound="Maracas"; }
); },
{ name="Tuned";
hotkey="n";
pads: (
{pad=0; channel="A Minor Pent 1"; sound="A2"; },
{pad=1; channel="A Minor Pent 1"; sound="C3"; },
{pad=2; channel="A Minor Pent 1"; sound="D3"; },
{pad=3; channel="A Minor Pent 1"; sound="E3"; }
);
}
);
1:19 p.m.
Ray Rashif wrote:
Sorry for the very random subject, but I figured
I'd need all the help
I can get.
I've read about this for a _little_ while (time constraints..arghhh)
on the WWW, and I've posted on www.edrum.info <http://www.edrum.info>
too. In case anyone here has better/fast/helpful
suggestions/advice/shizznit, I'm sort of cross-posting:
I just want one trigger, which I'll use for the kick drum. As such,
I'm interested to know if there are premade boards for the MIDI
conversion. Basically all I need is something which can take the
vibrations and convert them to electrical signals (piezo), and then
fed to something else that will convert that electrical signal to a
MIDI-ON message, after which I can plug it into the MIDI input of an
audio interface or use a MIDI-USB adapter to plug in to a USB port.
And regarding MIDI, if I want to take into consideration dynamics, and
let the piezo trigger MIDI messages with varying attack information,
how would it be done? So depending on the voltage generated, it'd be a
MIDI-ON but the final message to the computer (audio interface) would
be a "MIDI-ON && ATTACK == 75" sort of logic. Sorry for the noobish
description, have just started to dabble into (audio/midi) electronics.
I understand the concept and design roughly and I can move on by
reading the construction manual (refering to edrum's DIY guide), but
at the moment I'm looking for a quick way to build a trigger as I need
it asap (and no $$ for a real trigger kit/module).
Are you thinking of attaching the piezo to a real bass drum with kicker
(don't know if that's the right name), or forgetting about the drum and
having the kicker strike the piezo directly (which is what I'd do)?
There was a project in one of the linux magazines recently (Linux format
I think) to make a simple set of drum pads using an arduino board (
www.arduino.cc ), some piezos and a loudspeaker. I managed to adapt this
to send the trigger data back to the computer through the arduino's usb
cable and to a laptop. Then I wrote a short C program to translate the
incoming data into midi signals.
The way I worked out the attack was to work out the time it took in
samples between crossing a low threshold and the first maximum at the
start of the strike, divided by the height of the maximum. Piezos are a
bit tricky because they 'ring' after a hit, so you get an oscillating
signal for a while after the initial pulse, but the method I just said
seemed to work reasonably well.
The code that ran on the board is pasted below; I've also attached my C
code and an example config file for it if you want to look at that.
I haven't done much with this project since I got it to work, as the
piezo pads are a bit small to really play easily- more a toy than an
instrument. But the same approach might work quite nicely in the case
you're talking about.
andy
#define TRIGGER 50
#define RELEASE 20
#define PEAKTHRESH 700
#define MAXPADS 4
#define RELEASEDEL 100
#define SAMPLEDEL 10
int samples=0;
int piezoIn[]={0,1,2,3}; // analogue pin numbers for each pad.
int piezoState[]={0,0,0,0};
int piezoStartVal[]={0,0,0,0};
long piezoStartTime[]={0,0,0,0};
int piezoMax[]={170,170,170,170}; // maximum velocity values to use for
each pad. 170 is good for fingers - maybe higher for sticks.
int pattern=0;
void setup()
{
for (int i=0; i<MAXPADS; i++) {
pinMode(piezoIn[i],INPUT);
}
Serial.begin(19200);
}
void loop()
{
int val;
long time;
int midiVel;
int aveVel;
for (int i=0; i<MAXPADS; i++) {
val=analogRead(piezoIn[i]);
time=millis();
if ((val>=TRIGGER) && (piezoState[i]==0)) {
piezoState[i]=1;
piezoStartVal[i]=val;
piezoStartTime[i]=time;
samples=0;
} else if ( ( val >= PEAKTHRESH ) && (piezoState[i]==1) ) {
aveVel=(val-piezoStartVal[i])/(samples);
if ( (aveVel>piezoMax[i]) || (piezoStartVal[i]>PEAKTHRESH))
midiVel=127;
else
midiVel=(127*aveVel)/piezoMax[i];
Serial.print(i);
Serial.print(", ");
Serial.print(midiVel);
Serial.print(", ");
Serial.print(aveVel);
Serial.print(", ");
Serial.print(samples);
Serial.print(", ");
Serial.print(val);
Serial.print(", ");
Serial.print(piezoStartVal[i]);
Serial.print("\n");
piezoState[i]=2;
}
else if ((piezoState[i] > 0) && (val < RELEASE) &&
(time-piezoStartTime[i]>RELEASEDEL) ) {
piezoState[i]=0;
}
samples++;
}
delayMicroseconds(SAMPLEDEL); // not really needed but can adjust this
if necessary for some reason.
}
// config file for usbmidi
device="/dev/ttyUSB0";
kits:(
GM:(
(35,"Acoustic Bass Drum"), (59,"Ride Cymbal 2"),
(36,"Bass Drum 1"), (60,"Hi Bongo"),
(37,"Side Stick"), (61,"Low Bongo"),
(38,"Acoustic Snare"), (62,"Mute Hi Conga"),
(39,"Hand Clap"), (63,"Open Hi Conga"),
(40,"Electric Snare"), (64,"Low Conga"),
(41,"Low Floor Tom"), (65,"High Timbale"),
(42,"Closed Hi-Hat"), (66,"Low Timbale"),
(43,"High Floor Tom"), (67,"High Agogo"),
(44,"Pedal Hi-Hat"), (68,"Low Agogo"),
(45,"Low Tom"), (69,"Cabasa"),
(46,"Open Hi-Hat"), (70,"Maracas"),
(47,"Low-Mid Tom"), (71,"Short Whistle"),
(48,"Hi-Mid Tom"), (72,"Long Whistle"),
(49,"Crash Cymbal 1"), (73,"Short Guiro"),
(50,"High Tom"), (74,"Long Guiro"),
(51,"Ride Cymbal 1"), (75,"Claves"),
(52,"Chinese Cymbal"), (76,"Hi Wood Block"),
(53,"Ride Bell"), (77,"Low Wood Block"),
(54,"Tambourine"), (78,"Mute Cuica"),
(55,"Splash Cymbal"), (79,"Open Cuica"),
(56,"Cowbell"), (80,"Mute Triangle"),
(57,"Crash Cymbal 2"), (81,"Open Triangle"),
(58,"Vibraslap")
)
);
1:26 p.m.
On Friday 17 October 2008 10:49:22 Ray Rashif wrote:
I understand the concept and design roughly and I can
move on by reading
the construction manual (refering to edrum's DIY guide), but at the moment
I'm looking for a quick way to build a trigger as I need it asap (and no $$
for a real trigger kit/module).
Why not use one audio channel to feed in the piezo-signal to your soundcard
and use an amplitude tracker with a threshold detector in software (say, SC,
Pd and the like)?
That is probably the cheapest and quickest way to go.
You won't need to build much electronics for it (which is fun to do, but time
consuming).
sincerely,
Marije
1:29 p.m.
On Fri, 17 Oct 2008 22:49:22 +0800
"Ray Rashif" <schivmeister(a)gmail.com> wrote:
Sorry for the very random subject, but I figured
I'd need all the help I can
get.
I've read about this for a _little_ while (time constraints..arghhh) on the
WWW, and I've posted on www.edrum.info too. In case anyone here has
better/fast/helpful suggestions/advice/shizznit, I'm sort of cross-posting:
I just want one trigger, which I'll use for the kick drum. As such, I'm
interested to know if there are premade boards for the MIDI conversion.
Basically all I need is something which can take the vibrations and convert
them to electrical signals (piezo), and then fed to something else that will
convert that electrical signal to a MIDI-ON message, after which I can plug
it into the MIDI input of an audio interface or use a MIDI-USB adapter to
plug in to a USB port.
And regarding MIDI, if I want to take into consideration dynamics, and let
the piezo trigger MIDI messages with varying attack information, how would
it be done? So depending on the voltage generated, it'd be a MIDI-ON but the
final message to the computer (audio interface) would be a "MIDI-ON &&
ATTACK == 75" sort of logic. Sorry for the noobish description, have just
started to dabble into (audio/midi) electronics.
I understand the concept and design roughly and I can move on by reading the
construction manual (refering to edrum's DIY guide), but at the moment I'm
looking for a quick way to build a trigger as I need it asap (and no $$ for
a real trigger kit/module).
Look at:
http://arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1165833586
There is a specific example that more or less covers what you are
after. The forum is *very* helpful and are sure to be able to give you
whatever info you need to interface your trigger to the board.
The boards are very cheap (ready built) and easy to use. All the
software is Open Source
--
Will J Godfrey
http://www.musically.me.uk
5681
days inactive
5681
days old
linux-audio-user@lists.linuxaudio.org
6 comments
5 participants
participants (5)
-
andy baxter -
Folderol -
Nedko Arnaudov -
nescivi -
Ray Rashif