1st Project...A few ???'s before starting a 16 key touch sensitive midi keyboard

Hey there, I'm currently looking to create a 16-Key Midi Keyboard that is touch capacitive and will control a midi device (which will trigger sounds)...sort of like this:

http://www.instructables.com/id/Arduino-Touch-capacitive-Midi-keyboard/

Apparently you need:

  • Arduino Uno R3
  • 12 resistors (somewhere from 1M to 10M ohm)
  • jumper wires
  • 11 alligator clips
  • some conductive material (electric paint, aluminium foil etc.)
  • a software pogram that can handle midi
  • touchcapacitive library
  • the code & a software file

Now I've never done anything of this sort ...ever!...hence I have few N00B questions...

1 - If I want to make a 16 key version of this what items do I need more of from this list...and how many more of each?

2 - When creating the circuit on the breadboard...what's the smallest sized breadboard I can use that would accomodate '16-keys' and fit within a reasonable sized project box (not much bigger than the arduino uno if possible)?

3 - I noticed the arduino uno only has USB in/out...I need to go IN to another midi device which will take midi cable only...what's the best way to go about this? Convert USB to MIDI externally or can I also add a MIDI OUT to the Arduino Uno?

4 - Is there anything else I'm completely missing here in terms of approach?

Be gentle!

Thanks!

Some of the stuff from that link doesn’t fill me with a lot of confidence, for example from the posted code:

 for (int note=48;note<49;note++) {//from note 50 (D3) to note 69 (A4)

Also this:

Now it’s time to change the default UNO-dfu_and_usbserial_combined software on your arduino to a MIDI software.

This is USB-MIDI he is talking about. With a couple of components you can make serial-based MIDI which won’t involve reflashing your USB interface. I’ll see if I can dig up a schematic.

Thanks for the reply!

Yeah I'd like to keep everything as simple as possible, really appreciate any direction you can provide. :D

Here:

(Bottom part)

To transmit MIDI (which is all you need to do) you just need the MIDI connector and a couple of 220 ohm resistors. So far so good.

The Arduino has a total of 20 input/output pins (D0 to D13 and A0 to A5), so you could conceivably interface with 16 keys without too many issues.

When creating the circuit on the breadboard...what's the smallest sized breadboard I can use ...

You don't need the breadboard, that was just to make the connections.

I noticed the arduino uno only has USB in/out...I need to go IN to another midi device which will take midi cable only...what's the best way to go about this?

The circuit I posted, sending from Tx pin configured to the right baud rate (31250).

If I were you I'd get the sending working first, just mock up a small tune in code, and send that out. If your MIDI gadget plays it, that is the first step out of the way. Then add the capacitance stuff.

You can use hairless midi on you computer instead of a hardware interface.

Nick, thanks so much for the guidance....I think I'm ready to proceed with the project.

I'll just order a few extra resistors to accomodate the extra keys....

One last question...I noticed on the instructable it says "- 12 resistors (somewhere from 1M to 10M ohm)"

Is there not a specific OHM I'm looking for here? I would hate to buy the wrong ones....any suggestions or does it not matter?

@nilton61, thanks for your contribution but I am looking for hardware midi connection not software as this unit will be sending changes to a MIDI controlled turntable sending pitch change info related to note.

Thanks again guys!

I couldn't see a schematic on the Instructable site (only one of those Fritzing diagram). Judging by the first page you are using your fingers to complete a circuit where an analogRead detects the (small) current passing from 5V, through a high-value resistor, to be read. The exact resistor won't matter, it will just change the value being read.

BTW resistors are cheap.