Noise on lower end of DAC trace - can I fix this?

[Genesis]

hello
this is a prototype and i need to make the final schematics. and i use some smd resistors on my boards perhaps on this one. this is a friend who have my harp and i can't verify this now
but the schematic poste above was used when i make the board

[shobley]

Genesis,

I'm almost done with my harp...

I wanted to ask you where in the main control loop you output MIDI messages?

I have put my MIDI output routine just after the return signal and it works OK, but it does seem to slow down the beams a little...

Steve

[Genesis]

Hello
about the midi routine she was on the main program and use bits to know if a string is played.
the bit (flag) is set by the timer routine who draw the stings.

in the main routine if the flag go off the "note off" is sent

what is the microcontroler you use? his frequency?

greetings and happy new year

[shobley]

I'm using an Arduino (atmel atmega 168) at 16Mhz.

The MIDI output routine is slowing down the harp strings - but I have a control loop with timing delays - I never thought about using a timer interrupt for this.

When you play a note you can see the harp "flash" very quickly as the delay of sending MIDI stops the next refresh.

I am using TAOS light to voltage sensors in place of the photodiode. I made some (accidental) modifications to your beam detector circuit recently and it started working really well. I shall post you my modified circuit at some point.

One final question - how do you deal with multiple note triggers? When I trigger the note I get 2-3 notes sounding on NOTE ON, and 2-3 sounding when I take my hand away.

[Genesis]

ok
about the multi strings i use multi flags
each string use a proper flag to send each note on and note off.

for my midi routine i use the serial uart inside the atmel and note bit twidling. perhaps you loose time in bit twidling when you send the message.