I was fascinated when i saw some drumkit implementations and got frustrated afterwards by getting multiple note on messages
when hitting the piezo's...
As i am new in the arduino community and also a newbee in electronics in general, i replicated the schematic from SpikenzieLabs and
used todbot's code,made it work but got many multiple NoteOn messages with single hits.Many users had pretty good results though.
I always like to check on how things are done by others first and then do it another way (pride,egotism etc...)
with a little manipulation it can send MIDI notes with velocity information.
For minimising delayed response i used an alternate firmware for the U8 chip so it registered as a general midi device.
NO custom drivers,NO extra software (serial to MIDI port relay..)
The link for the MIDI MOCO for LUFA firmware:
http://web.mac.com/kuwatay/morecat_lab./MocoLUFA.html
this could be helpfull for other sensors types too and for many projects not related to sound.
please advice me where to post this code for this is my first post here and my first forum post EVER...(sounds lame,i know hehee;)
so here's my way of detecting Local Maxima on consecutive analogreads, it includes the
BlinkLed function in case someone congests his Tx line and cannot re-load code,i happened to me...
enjoy,comment!!
int Threshold = 100;
int Hit;
void setup(){
pinMode (13,OUTPUT);
BlinkLed (3,500);
Serial.begin(38400);
}
void loop(){
for (int i = 0;i<=5;i++){ //Cycle through ADC channels.
if (analogRead(i)>Threshold){ //If current channel reading exceeds threshold
Hit = AnalogMaxima (i,Threshold,2); //find local maxima and return value.
if (Hit == 1025 || Hit == 0){ //if still ascending or below threshold,
break; //go to next ADC channel.
}
else{
Serial.println(Hit); //Show maxima. or play midi note ;)
}
}
}
}
//--------------------------------------------------------------------------------
/* AnalogMaxima compares succesive readings from ADC on channel AnalogCh
and returns :
1025 if voltage is decreasing,so that only the maxima is returned.
0 if below threshold.
or returns the highest value when voltage starts to drop (local maxima).
AnalogCh : Channel on the ADC to check for maxima.
Threshold : Lowest voltage reading to begin maxima evaluation.
Delay : Delay between succesive readings.
*/
int AnalogMaxima (int AnalogCh, int Threshold, int Delay){
int check1; //variable to store first reading.
int check2; //variable to store second reading.
check1 = analogRead(AnalogCh); //Assing first reading
delay(Delay); //wait
check2 = analogRead (AnalogCh); //Assing second reading.
if (check1>check2){ //If voltage is DECREASING (no maxima)...
return 1025; //end loop and return 1025.
}
else{
while (analogRead(AnalogCh)>Threshold){ //While above threshold and RISING
check1 = analogRead(AnalogCh); //Assing first reading
delay(Delay/2); //wait
check2 = analogRead (AnalogCh); //Assing second reading.
delay(Delay/2); //wait,and loop unless...
if (check1>check2){ //voltage drop is observed
return check1; //if so return highest value :)
}
}
}
} // end of AnalogMaxima //
//--------------------------------------------------------------------------------
//--------------------------------------------------------------------------------
/* BlinkLed ensures there is enough time in the start of the sketch to download a
new sketch if desired,in case that the serial tx is constantly sending data.
Times : times to blink.
Delay : delay between blinks.
*/
void BlinkLed (int Times, int Delay){
for (int i = 1; i<=Times; i++){
digitalWrite (13,HIGH);
delay(Delay);
digitalWrite (13,LOW);
delay(Delay);
}
} // end of BlinkLed //
//--------------------------------------------------------------------------------
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