pad triggers: built in or external?

[mirrorcrypt]

Hi, I'd like to trigger samples in a computer and some outboard samplers, and record that in real time in the mbsequencer. Would 'pad' triggers built into the case and connected to the analog inputs of the new core module have less latency than an external box of pads (eg. a korg pad kontrol) connected via a midi input? I'm debating building pads into an mbseq but if there isn't a useful improvement in terms of latency then maybe it's not worth the trouble.

Thanks,

Dave.

[lylehaze]

Trigger to MIDI conversion has different requirements than regular analog to digital conversion.

You might be better served with a project tht is designed exactly for that.

Here's a popular choice:http://www.edrum.info/

Have Fun

[mirrorcrypt]

Hey Lyle, thanks for the reply! I had a look at the edrum and while that looks pretty cool, and I'd like to make use of something like that in the studio, I was more thinking about pads like on an MPC or pad kontrol. I was hoping for some advice about advantages/disadvantages to the pad voltage signal entering via the AIN or via midi.

I did some digging and found this company: http://sensitronics.com/products/force_sensing_resistor.htm

They seem to make the MPC sensors and I thought I could do something with that. I also thought this looked interesting: http://sensitronics.com/products/matrix_array.htm

Anyway, thanks again. Maybe while waiting to build this thing I'm totally over-thinking it! It's a great project and thanks to all involved.

Dave.

[lylehaze]

Looks interesting,

_most_ electronic drum triggers are that I have seen are piezo.

They actually generate a brief voltage spike when struck. They are force sensitive, but the voltage spike is very brief.

These sensors you are looking at are resistive, and of course can detect how hard you are pressing continuously. If you're just experimenting, I recall seeing something very close  to these that was homebrewed. Make the contact patterns in the same way, 2 layer or 1 layer interleaved, then use a bit of the black conductive foam that chips are often shipped in. As you compress the foam, the resistance across the traces should drop a bit. You could even "fake" the contact surfaces by using stripboard above and below the foam, with the contact traces facing the foam.

Regarding feeding these to an analog input, there are "suggestions" in the MChip documents that voltages being fed into the ADC have as low an impedance as possible.  The datasheet describes more details, followed by this in bold print:The maximum recommended impedance for analog sources is 2.5 k?.

I don't know if the commercial device you are looking at is buffered, but the hack I described would need to be. Of course that would also allow you to "tune" with gain and offset to your liking.

You MAY be able to see SOMETHING if you connect directly without any help, but the resolution and accuracy of the results will be less than ideal.

Have Fun,

LyleHaze