STEPS TO FOLLOW:
Indeed, the 3Dpad doesn't work on MEGA without a small modification. It concerns the SPI port pins: 11 (MOSI) and 13 (SCK) for the UNO. Unfortunately the SPI port is not wired on those pins for MEGA.
See below the modification details:
1) you have to cut the two pins on the 3Dpad shield (see top right in the picture):
2) solder two wires on those pins on the PCB 3Dpad:
3) bring those wires in the right place (MOSI and SCK) or on the MEGA board:
I used 3Dpad shield on an Ardunio MEGA, using theUART port N°2 for the MIDI signal, and the UART/USB for the 3Dpad visualization in the same time.
Also I used a MIDI/USB interface to interact with a music software on my laptop. For instance, I'm still using this one today: http://www.roland.com/
In order to use an UART port as MIDI port, you'll have to make this kind of wiring:
First of all, you'll have to install the 3Dpad's librairy for Arduino. Best is to follow the standard 3Dpad tutorial:
Once it's done, you can use the specific sketch below for using 3Dpad as a MIDI controller:
For the first test, I used a very usefull SW: midiox , it will show you if the MIDI signals are doing well.
Everything seems to be OK? Enyoy now!