• Installation of the Display:


  • Multipins for knobs

Sharing digital pins 2 and 3 (INT0 and INT1). “The processor at the heart of any Arduino has two different kinds of interrupts: “external”, and “pin change”. There are only two external interrupt pins on the ATmega168/328 (ie, in the Arduino Uno/Nano/Duemilanove), INT0 and INT1, and they are mapped to Arduino pins 2 and 3. These interrupts can be set to trigger on RISING or FALLING signal edges, or on low level. The triggers are interpreted by hardware, and the interrupt is very fast. The Arduino Mega has a few more external interrupt pins available“. For sharing pins I am using MCP23017 chip  


1  GPB0  8
2  GPB1  9
3  GPB2  10
4  GPB3  11
5  GPB4  12
6  GPB5  13
7  GPB6  14
8  GPB7  15
9  Vdd  power: 5V
10  Vss  ground
11  NC [no connection]
12  SCL  A5
13  SDA  A4
14  NC  [no connection]
15 Address: A0 hardware address with ground or power connection
16 Address: A1 hardware address with ground or power connection
17 Address: A2 hardware address with ground or power connection
18  RESET  power 5V
19 INTB [no connection]
20  INTA [no connection]
21  GPB0  0
22  GPB1 1
23  GPB2  2
24  GPB3  3
25  GPB4  4
26  GPB5  5
27  GPB6  6
28  GPB7  7


MCP23017 datasheet


  • Assigning addresses and setting values for each button on Trellis:



  • Polishing sides of the keypads.IMG_8734
  • I installed Ubuntu on Raspberry Pi 2 with Pure Data. I have a sequencer almost ready and a music player with changing speed, volume, duration and some other options. I also have a set on buttons that I will use for this project and I ordered 12 more sets of this buttons for the whole device. I still will need to figure out what battery will be better to use and if I can use Arduino as an external microprocessor to give it some of the work and make RP work faster. Also I need to find a good audio shield for RP. I also started programming some of effects for audio files and 3d model of the device.
  •  want to install Windows 10 IoT on Raspberry Pi 2 and to run an external MaxMSP Application on it. Still need to test it. However, windows 10 reviews say that it’s not going to work. And that “Digital audio is completely ignored”. Link to the review.  Otherwise I need to work in PureData on Linux