Foot Piano with Midi Output
ajajack
Posts: 26
Hello,
I am trying to create a large touch sensitive foot piano that is able to output to midi on my BASIC Stamp.· I want it to be able to play multiple notes at once.· My original setup was going to use 12 of the i/o pins and just create a switch for each note.· But my problem is how to interface with midi and how to have it be able to play multiple notes at once.· I am very new to programming the BASIC Stamp so any help would be great.
Thank You,
AJ
I am trying to create a large touch sensitive foot piano that is able to output to midi on my BASIC Stamp.· I want it to be able to play multiple notes at once.· My original setup was going to use 12 of the i/o pins and just create a switch for each note.· But my problem is how to interface with midi and how to have it be able to play multiple notes at once.· I am very new to programming the BASIC Stamp so any help would be great.
Thank You,
AJ
Comments
Here's the MIDI format:
http://www.borg.com/~jglatt/tech/midispec.htm
Here's how to hook it up:
here's a good resource for Basic Stamp MIDI output -http://www.audiomulch.com/midipic/
Now you just have to figure out how to build the foot pedal.
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Have Fun
TR
Post Edited (TechnoRobbo) : 8/24/2007 11:46:54 AM GMT
Basic Stamp Code
statusbyte var byte···· 'MIDI status; controller, noteon, or pitchbend
data1 var byte········· 'first data byte, eg. controller or note number
data2 var byte········· 'second MIDI data byte, eg. value or velocity
midioutpin con 0······· 'pin connected to MIDI out connector
midibaudmode con 32780
serout midioutpin, midibaudmode, [noparse][[/noparse]statusbyte, data1, data2]
Note ON
Status
$90 to $9F where the low nibble is the MIDI channel.
Data
Two data bytes follow the Status.
The first data is the note number. There are 128 possible notes on a MIDI device, numbered 0 to 127 (where Middle C is note number 60). This indicates which note should be played.
The second data byte is the velocity, a value from 0 to 127. This indicates with how much force the note should be played (where 127 is the most force). It's up to a MIDI device how it uses velocity information. Often velocity is be used to tailor the VCA (Voltage Controlled Amplifiers*)·attack time and/or attack level (and therefore the overall volume of the note). MIDI devices that can generate Note On messages, but don't implement velocity features, will transmit Note On messages with a preset velocity of 64.
A Note On message that has a velocity of 0 is considered to actually be a Note Off message, and the respective note is therefore released.
Note OFF
Status
$80 to $8F where the low nibble is the MIDI channel.
Data
Two data bytes follow the Status.
The first data is the note number. There are 128 possible notes on a MIDI device, numbered 0 to 127 (where Middle C is note number 60). This indicates which note should be released.
The second data byte is the velocity, a value from 0 to 127. This indicates how quickly the note should be released (where 127 is the fastest). It's up to a MIDI device how it uses velocity information. Often velocity will be used to tailor the VCA release time. MIDI devices that can generate Note Off messages, but don't implement velocity features, will transmit Note Off messages with a preset velocity of 64.
TR's Footnote:
*VCA - Voltage controlled amplifier is the component on an analog synth that controls the volume "Envelope" the usual components are -·Attack( volume fade in time), Decay (initial volume fade out after attack),Sustain (level the volume stays at while the key is held),·and Release (volume fade out time).· With the onset of Digital, the Envelope shapes became more complex.
···
Go to http://en.wikipedia.org/wiki/ADSR_envelope·for more info
This Example Plays 2 bass note simltaneously·1 octave apart in and old fashion random sequencer style (I was inspired by Kraftwerk early on). changing the value of "seed" changes pattern:
'Techno Robbo's Random Bass Thump Demo
' {$STAMP BS2}
' {$PBASIC 2.5}
statusbyte VAR Byte···· 'MIDI status; controller, noteon, or pitchbend
data1 VAR Byte········· 'note
data2 VAR Byte········· 'octave
result VAR Word
notecount VAR Byte
seed CON 0·············· 'change seed to change pattern (0-65535)
midioutpin CON 14······· 'pin connected to MIDI out connector
midibaudmode CON 32780
SEROUT midioutpin, midibaudmode, [noparse][[/noparse]$B0,7,127] 'Full Volume
PAUSE 1
SEROUT midioutpin, midibaudmode, [noparse][[/noparse]$B0,123,0] 'all notes off
PAUSE 1
SEROUT midioutpin, midibaudmode, [noparse][[/noparse]$B0,120,0] 'all sound off
PAUSE 500
SEROUT midioutpin, midibaudmode, [noparse][[/noparse]$C0, 33] ' change instrument to bass
notecount=0
result=seed
DO
RANDOM result
data1=result// 8
data2=data1
statusbyte = $90
LOOKUP data1,[noparse][[/noparse]24,26,28,29,31,33,35,36], data1
LOOKUP data2,[noparse][[/noparse]36,38,40,41,43,45,47,48],· data2
SEROUT midioutpin, midibaudmode, [noparse][[/noparse]statusbyte, data1, 127]
PAUSE 1
SEROUT midioutpin, midibaudmode, [noparse][[/noparse]statusbyte, data2, 127]
PAUSE 60
SEROUT midioutpin, midibaudmode, [noparse][[/noparse]statusbyte, data1, 0]
PAUSE 1
SEROUT midioutpin, midibaudmode, [noparse][[/noparse]statusbyte, data2, 0]
PAUSE 63
notecount=notecount + 1 // 32······ 'recycle pattern
IF notecount=0 THEN result=seed
LOOP
For a more comprehensive Demo with variable note cycles - 65536 paterns·,variable tempo ,selectable note value, see below attachment.
·
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Have Fun
TR
Post Edited (TechnoRobbo) : 8/28/2007 1:37:23 AM GMT