Parts

• A first generation Raspberry Pi, Model B+ (the one with 4 USB ports), or the more powerful Raspberry Pi 2


• A class 9 MicroSD card with some 8 Gigs or more


• 1 panel mountable Ethernet socket with cable (from Adafruit)


• 2 panel mountable USB Type A-M to A-F sockets (from Adafruit)


• 1 panel mountable HDMI socket (Adafruit)


• USB micro-B cable (again Adafruit)


• 5V Pro Trinker, also from Adafruit


• Adafruit also has some nice multicolor 16x2 LCDs (No, I'm not having stock options with them!)


• Standalone ATmega 328P chip, eventually a DIL socket to allow for easy replacement


• 7 LEDs in different colors, 1 green, 2 yellow, 2 orange, 2 red (or whatver colors you like)


• 2 x 220 ohm resistors, 2 x potentiometers, some wires, header connectors, flat cable, some bakelite boards (or perma protoboard from Ada....), etc

Make new Room

OSMC and Package Installation

apt-get update

apt-get install vim build-essential python-pip python2.7-dev python-smbus git

pip install RPi.GPIO netifaces uptime

cd ~

git clone https://github.com/adafruit/Adafruit_Python_CharLCD.git

cd Adafruit_Python_CharLCD

sudo python setup.py install

rm -rf ~/Adafruit_Python_CharLCD

Hooking up the LCD

Hooking up the "Glowing LED"

for dc in range(10, 100, 5):

    p.ChangeDutyCycle(dc)

    time.sleep(0.2)

for dc in range(100, 10, -5):

    p.ChangeDutyCycle(dc)

    time.sleep(0.1)

The VU Meter

Make Front Panel Keys Functional

/*

 * cobalt_keys - read cobalt front panel buttons to control Kodi

 *

 * Copyright (c) 2015, Gianpaolo Del Matto, www.phunsites.net

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

 *

 * 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

 *

 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this

 *    software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS

 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,

 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 */





/*  

 *   include pro trinket library

 *   

 *   for some reason, which I had no time to resolve, this behaves very differently with my setup.

 *   according to official examples, only the single "include <ProTrinketKeyBoard.h>" is required.

 *   

 *   however, if I included only the <ProTrinketKeyBoard.h> file, I would always end up with linker errors.

 *   only by adding the full path includes for <cmdline_defs.h>, <ProTrinketKeyboard.h>

 *   and <usbconfig.h>, the compiler would actually be happy with me.

 */

#include </full/path/to/Arduino/libraries/Pro_Trinket_USB_Keyboard_Library-master/cmdline_defs.h>

#include </full/path/to/Arduino/libraries/Pro_Trinket_USB_Keyboard_Library-master/ProTrinketKeyboard.h>

#include </full/path/to/Arduino/libraries/Pro_Trinket_USB_Keyboard_Library-master/usbconfig.h>

#include <ProTrinketKeyboard.h>





/* key definitions */

#define PIN_ARROW_LEFT A0

#define PIN_ARROW_RIGHT A1

#define PIN_ARROW_UP A2

#define PIN_ARROW_DOWN A3

#define PIN_ENTER A4

#define PIN_BACKSPACE A5



/* LED definition */

#define PIN_LED 13



/* arrays to track our states */

int state_KEY_ARROW_LEFT = 1;

int state_KEY_ARROW_RIGHT = 1;

int state_KEY_ARROW_UP = 1;

int state_KEY_ARROW_DOWN = 1;

int state_KEY_ENTER = 1;

int state_KEY_BACKSPACE = 1;



/* init */

void setup() {

      // enable LED pin

      pinMode(PIN_LED, OUTPUT);

      digitalWrite(PIN_LED, LOW);

  

      // button pins as inputs

      pinMode(PIN_ARROW_RIGHT, INPUT);

      pinMode(PIN_ARROW_LEFT, INPUT);

      pinMode(PIN_ARROW_UP, INPUT);

      pinMode(PIN_ARROW_DOWN, INPUT);

      pinMode(PIN_ENTER, INPUT);

      pinMode(PIN_BACKSPACE, INPUT);



      // enable internal pullups

      digitalWrite(PIN_ARROW_RIGHT, HIGH);

      digitalWrite(PIN_ARROW_LEFT, HIGH);

      digitalWrite(PIN_ARROW_UP, HIGH);

      digitalWrite(PIN_ARROW_DOWN, HIGH);

      digitalWrite(PIN_ENTER, HIGH);

      digitalWrite(PIN_BACKSPACE, HIGH);

     

      // start USB

      TrinketKeyboard.begin();

}



/* main loop */

void loop() {

      // always reset the indicator LED, switch it off and make a short sleep

      digitalWrite(PIN_LED, LOW);

      delay(5); // stay below 10 ms or the pseudo-keyboard may get disconnected, see below

      

      // the poll function must be called at least once every 10 ms or cause a keystroke

      // if it is not, then the computer may think that the device has stopped working, and give errors

      TrinketKeyboard.poll();



      // read all inputs at once so even concurrent presses could be detected this way,

      // though I propably wont ever need it

      //

      int r_KEY_ARROW_RIGHT = digitalRead(PIN_ARROW_RIGHT);

      int r_KEY_ARROW_LEFT = digitalRead(PIN_ARROW_LEFT);

      int r_KEY_ARROW_UP = digitalRead(PIN_ARROW_UP);

      int r_KEY_ARROW_DOWN = digitalRead(PIN_ARROW_DOWN);

      int r_KEY_ENTER = digitalRead(PIN_ENTER);

      int r_KEY_BACKSPACE = digitalRead(PIN_BACKSPACE);





      // handle ARROW RIGHT key

      // by checking inverse state, I enforce an absolute debounce,

      // which means, that only one keypress is detected, no matter

      // how long the key is actually pressed.

      // ok, this also prevents things like "key repeat after nn ms",

      // but actually I don't want this: I want to press the keys

      // on the front panel repeatedly. As it turned out for me,

      // the haptic feedback in Kodi seemed more tactile

      // to me than without it.

      //

      if(r_KEY_ARROW_RIGHT != state_KEY_ARROW_RIGHT) {

        

        // right, we send a key press only if the input reads LOW

        // also, I'm quickly flashing the LED on the trinket,

        // that's actually only as a debugging aid to indicate, that

        // "something" was received.

        //

        if(r_KEY_ARROW_RIGHT == LOW) {

          digitalWrite(PIN_LED, HIGH);

          TrinketKeyboard.pressKey(0, KEYCODE_ARROW_RIGHT);

        }



        // save the current key state to compare key states on next

        // iteration again. we even do so when no actual processing

        // happened (INPUT did NOT read LOW)

        //

        state_KEY_ARROW_RIGHT = r_KEY_ARROW_RIGHT;

      }



      // next sections are identical to the one above, they follow the same logic.

      // yes, I know, I did not respect the DRY (don't repeat yourself) pragma ;-)

      // I should propably implement a bitwise-ANDed matrix to make this more lean.



      // handle ARROW LEFT key

      if(r_KEY_ARROW_LEFT != state_KEY_ARROW_LEFT) {

        if(r_KEY_ARROW_LEFT == LOW) {

          digitalWrite(PIN_LED, HIGH);

          TrinketKeyboard.pressKey(0, KEYCODE_ARROW_LEFT);

        }

        state_KEY_ARROW_LEFT = r_KEY_ARROW_LEFT;

      }



      // handle ARROW UP key

      if(r_KEY_ARROW_UP != state_KEY_ARROW_UP) {

        if(r_KEY_ARROW_UP == LOW) {

          digitalWrite(PIN_LED, HIGH);

          TrinketKeyboard.pressKey(0, KEYCODE_ARROW_UP);

        }

        state_KEY_ARROW_UP = r_KEY_ARROW_UP;

      }



      // handle ARROW_DOWN key

      if(r_KEY_ARROW_DOWN != state_KEY_ARROW_DOWN) {

        if(r_KEY_ARROW_DOWN == LOW) {

          digitalWrite(PIN_LED, HIGH);

          TrinketKeyboard.pressKey(0, KEYCODE_ARROW_DOWN);

        }

        state_KEY_ARROW_DOWN = r_KEY_ARROW_DOWN;

      }



      // handle ENTER key

      if(r_KEY_ENTER != state_KEY_ENTER) {

        if(r_KEY_ENTER == LOW) {

          digitalWrite(PIN_LED, HIGH);

          TrinketKeyboard.pressKey(0, KEYCODE_ENTER);

        }

        state_KEY_ENTER = r_KEY_ENTER;

      }





      // handle BACKSPACE key

      if(r_KEY_BACKSPACE != state_KEY_BACKSPACE) {

        if(r_KEY_BACKSPACE == LOW) { 

          digitalWrite(PIN_LED, HIGH);

          TrinketKeyboard.pressKey(0, KEYCODE_BACKSPACE);

        }

        state_KEY_BACKSPACE = r_KEY_BACKSPACE;

      }



      // reset pressed key

      TrinketKeyboard.pressKey(0, 0);

}

The Wiring Diagram

cobalt_pi - The heart of it all

Bringing It All Together