Then I soldered similar circuits to the analog inputs 5, 4, 3, and 2 like I used for the push buttons. 10K resistor pull the input down to the ground. Then the same input is connected to the +5V via a jumper and a 500 ohm resistance. The jumper is then connected to the external connector. By shorting the external connector it works similarly as a push button. If a variable resistor is connected to the external connector then it works as an analog input.

Here is a picture about the board:

Analog inputs and their connections to the back panel

I disassembled the box. Well it is not the best for this project, since it is closing with clips and not screws but it was free so I can live with that. I tried my board into it and found that I have to cut a couple of centimeters from the end of the board.

Here are some pictures about the box and the cut board:

ZIP drive box

Now the board is shorter

As you can see I cut two holes on the side of the box. They are for the external power connector and usb connector of the arduino. I still have to cut a hole for the LCD and drill some holes for the potentiometers and buttons.

I also assembled connectors to the back panel of the box:

Back panel

I soldered jumper cables to the connectors. Two connector is connected to a single jumper cable. The second pins of each connector are connected together and the will be connected to the ground. I also use a jumper cable for that.

When I will get the second potentiometer I will connect its side pins to the corresponding pins on the other potentiometer. The middle pin will be connected to the free wire on the second cable.

I will use the connected potentiometer for setting a treshold value. For instance it can be used for calibrating microphone input. The second potentiometer will be used to input delay values. I will use a precision potentiometer (turns 10x) for that.

Here is a picture of the hardware:

Potentiometer added

I also added the treshold input to the code:

// include the library code:
 #include <LiquidCrystal.h>

 const int numRows = 2;
 const int numCols = 16;

 //Digital pins
 const int lcdBackLightPin = 12;
 const int upButtonPin = 6;
 const int downButtonPin = 5;
 const int setButtonPin = 4;
 const int resetButtonPin = 3;

 //Analog pins
 const int tresholdPin = 0;

 char* mainMenu[]={"start", "delay", "treshold", "test"};
 int mainMenuIndex = 0;
 int mainMenuNextItem = 1;
 int mainMenuItemNum = 4;
 boolean menuUpdate = false;

 int treshold = 0;

 // initialize the library with the numbers of the interface pins
 LiquidCrystal lcd(13, 11, 10, 9, 8, 7);

 void setup() {
   // set up the LCD's number of rows and columns:
   lcd.begin(numRows, numCols);
   lcd.clear();
   lcd.setCursor(0, 0);
   lcd.print(">");
   lcd.setCursor(2, 0);
   lcd.print(mainMenu[mainMenuIndex]);
   lcd.setCursor(2, 1);
   lcd.print(mainMenu[mainMenuNextItem]);
   digitalWrite(lcdBackLightPin, HIGH);

   pinMode(lcdBackLightPin, OUTPUT);
   pinMode(upButtonPin, INPUT);
   pinMode(downButtonPin, INPUT);
   pinMode(setButtonPin, INPUT);
   pinMode(resetButtonPin, INPUT);

 }

 void setTreshold()
 {
   int cursorOn = 1;
   delay(300);

   while(!digitalRead(setButtonPin))
   {
     treshold = analogRead(tresholdPin);
     lcd.clear();
     lcd.setCursor(0, 0);
     lcd.print("Treshold:");
     lcd.setCursor(0, 1);
     if(cursorOn)
     {
       lcd.print("> ");
       cursorOn = 0;
     }
     else
     {
       lcd.print("  ");
       cursorOn = 1;
     }

     lcd.print(treshold);

     delay(300);
   }
 }

 void loop() {
   if(digitalRead(upButtonPin))
   {
     mainMenuIndex++;
     if(mainMenuIndex >= mainMenuItemNum)
     {
       mainMenuIndex = 0;
     }  
     mainMenuNextItem++;
     if(mainMenuNextItem >= mainMenuItemNum)
     {
       mainMenuNextItem = 0;
     }
     menuUpdate = true;
   }
   else if(digitalRead(downButtonPin))
   {
     mainMenuIndex--;
     if(mainMenuIndex < 0)
     {
       mainMenuIndex = mainMenuItemNum - 1;
     }  
     mainMenuNextItem--;
     if(mainMenuNextItem < 0)
     {
       mainMenuNextItem = mainMenuItemNum - 1;
     }
     menuUpdate = true;
   }
   else if(digitalRead(setButtonPin))
   {
     switch(mainMenuIndex)
     {
       /*
       case 0:     
       break;

       case 1:
       break;
       */
       case 2: setTreshold();
         menuUpdate = true;      
       break;
       /*  
       case 3:
       break;

       default:
       */
     }
   }

   if(menuUpdate)
   {   
     lcd.clear();
     lcd.setCursor(0, 0);
     lcd.print(">");
     lcd.setCursor(2, 0);
     lcd.print(mainMenu[mainMenuIndex]);
     lcd.print(" <");
     lcd.setCursor(2, 1);
     lcd.print(mainMenu[mainMenuNextItem]);
     menuUpdate = false;
     delay(300);
   }
 }

After reviewing my half made board and my last post I found that I have the following pins free:

Digital I/O:  2, 1, 0

Analog input: 0, 1, 2, 3, 4, 5

I will use the digital pins as digital outputs.

The first two analog pins (0 and 1) will be used for built in potentiometers.

The analog 2 and 3 pins will be configured as digital inputs and they will have similar circuits like the push buttons. The only difference is that we will replace the button with a connector.

The analog 4 and 5 will be directly connected to connectors.

Now, I have plan Lets solder!

// include the library code:
 #include <LiquidCrystal.h>

 const int numRows = 2;
 const int numCols = 16;

 const int lcdBackLightPin = 12;
 const int upButtonPin = 6;
 const int downButtonPin = 5;
 const int setButtonPin = 4;
 const int resetButtonPin = 3;

 char* mainMenu[]={"start", "delay", "test"};
 int mainMenuIndex = 0;
 int mainMenuNextItem = 1;
 int mainMenuItemNum = 3;
 boolean menuUpdate = false;

 // initialize the library with the numbers of the interface pins
 LiquidCrystal lcd(13, 11, 10, 9, 8, 7);

 void setup() {
 // set up the LCD's number of rows and columns:
 lcd.begin(numRows, numCols);
 lcd.clear();
 lcd.setCursor(0, 0);
 lcd.print(">");
 lcd.setCursor(2, 0);
 lcd.print(mainMenu[mainMenuIndex]);
 lcd.setCursor(2, 1);
 lcd.print(mainMenu[mainMenuNextItem]);
 digitalWrite(lcdBackLightPin, HIGH);

 pinMode(lcdBackLightPin, OUTPUT);
 pinMode(upButtonPin, INPUT);
 pinMode(downButtonPin, INPUT);
 pinMode(setButtonPin, INPUT);
 pinMode(resetButtonPin, INPUT);

 }

 void loop() {
 if(digitalRead(upButtonPin))
 {
 mainMenuIndex++;
 if(mainMenuIndex >= mainMenuItemNum)
 {
 mainMenuIndex = 0;
 }  
 mainMenuNextItem++;
 if(mainMenuNextItem >= mainMenuItemNum)
 {
 mainMenuNextItem = 0;
 }
 menuUpdate = true;
 }
 else if(digitalRead(downButtonPin))
 {
 mainMenuIndex--;
 if(mainMenuIndex < 0)
 {
 mainMenuIndex = mainMenuItemNum - 1;
 }  
 mainMenuNextItem--;
 if(mainMenuNextItem < 0)
 {
 mainMenuNextItem = mainMenuItemNum - 1;
 }
 menuUpdate = true;
 }

 if(menuUpdate)
 {   
 lcd.clear();
 lcd.setCursor(0, 0);
 lcd.print(">");
 lcd.setCursor(2, 0);
 lcd.print(mainMenu[mainMenuIndex]);
 lcd.print(" <");
 lcd.setCursor(2, 1);
 lcd.print(mainMenu[mainMenuNextItem]);
 menuUpdate = false;
 delay(300);
 }

 }

You can download the file from here: xISTIxHSPC

Buttons assembled

As you can see, I put every button connector two a new column. This way it was easy to wire them and I needed to make cuts only between the connector pins. I also changed the code of the controller:

// include the library code:
 #include <LiquidCrystal.h>

 const int numRows = 2;
 const int numCols = 16;

 const int lcdBackLightPin = 12;
 const int upButtonPin = 6;
 const int downButtonPin = 5;
 const int setButtonPin = 4;
 const int resetButtonPin = 3;

 // initialize the library with the numbers of the interface pins
 LiquidCrystal lcd(13, 11, 10, 9, 8, 7);

 void setup() {
 // set up the LCD's number of rows and columns:
 lcd.begin(numRows, numCols);
 lcd.clear();
 lcd.setCursor(5, 1);
 lcd.print("XistiX");
 digitalWrite(lcdBackLightPin, HIGH);

 pinMode(lcdBackLightPin, OUTPUT);
 pinMode(upButtonPin, INPUT);
 pinMode(downButtonPin, INPUT);
 pinMode(setButtonPin, INPUT);
 pinMode(resetButtonPin, INPUT);
 }

 void loop() {
 if(digitalRead(upButtonPin))
 {
 lcd.setCursor(0, 0);
 lcd.print("UP Button");
 }
 else if(digitalRead(downButtonPin))
 {
 lcd.setCursor(0, 0);
 lcd.print("DOWN Button");
 }
 else if(digitalRead(setButtonPin))
 {
 lcd.setCursor(0, 0);
 lcd.print("SET Button");
 }
 else if(digitalRead(resetButtonPin)

)

 {

 lcd.setCursor(0, 0);

 lcd.print("RESET Button");

 }

 else

 {

 lcd.setCursor(0, 0);

 lcd.print("            ");

 }

 }

It prints to the screen which button is pressed. When you check the source you will notice that buttons actually has a priority order and you can’t press two more than one button at the same time. I used an if else if structure. I will change this later. It is simply so because it was the easiest to test the buttons and update the screen.

You can download the code as a file from here: xISTIx_Buttons

Push button circuit

I have put a two pin connector to a stripe and made a cut between the pins. then I connected one pin (the upper one in the picture) via a 10 kohm resistor to the ground. The same pin is also connected to pin 6 of the arduino.  The other pin is connected to 5v via a 500 ohm resistor. The push button shorts the two pins.

I have modified the LCD test program a bit. Now the LCD background light is on when the push button is pressed. It is just for testing purposes. Later I will change this.

Here is the code: HelloWorldLCDButton

LCD circuit ready

Hello World!

And here is the final design:

Final LCD circuit design

I also promised to upload the LCD test program:

// include the library code:
 #include <LiquidCrystal.h>

 const int numRows = 2;
 const int numCols = 16;

 const int lcdBackLightPin = 12;

 // initialize the library with the numbers of the interface pins
 LiquidCrystal lcd(13, 11, 10, 9, 8, 7);

 void setup() {
 // set up the LCD's number of rows and columns:
 lcd.begin(numRows, numCols);
 lcd.clear();
 lcd.setCursor(2, 0);
 lcd.print("Hello World!");

 pinMode(lcdBackLightPin, OUTPUT);
 }

 void loop() {
 digitalWrite(lcdBackLightPin, HIGH);
 lcd.setCursor(5, 1);
 lcd.print("xISTIx");
 delay(500);
 digitalWrite(lcdBackLightPin, LOW);
 lcd.setCursor(5, 1);
 lcd.print("XistiX");
 delay(500);
 }

Source file is here: xISTIx_Hello_LCD

My source file is based on this example: http://arduino.cc/en/Tutorial/LiquidCrystal

I just simplified the loop and changed the pin numbers according to my circuit. I also added the control for the LCD back light on pin 12.

Finally a comment for Linux 64 bit users. If you use the arduino package I have suggested earlier, you might face some compilation problem. It is because the LCD library is old in that package. I simply downloaded the arduino017 32 bit Linux software from the official arduino site and copied the LCD library from there. It works fine.