Monday, April 15, 2013

How to make a quick Arduino to Cadaces adapter.



Some people asked me for a simpler way to interface the Cadaces modules to an Arduino, so here it is!

All you need to do this is a five pin header and four jumper wires.  Insert the five pin header into D1 through D5.  Then plug the cable from the display into those five pins so the other five pins hang off to the right.  Add the four jumper wires according to the schematic.
 Here is a picture of the quick adapter in operation.  The green wire if 5 volts going to power the sign.

Here are the pin number changes to the code to make it work;

// Pins for the row drivers
int row1Pin = 2;            //R1
int row2Pin = 7;            //R2
int row3Pin = 1;            //R3
int rowEnable = 8;        //REN
int rclockPin = 6;          //RCK
int clockPin = 3;           //SCK
int dataPin = 5;             //RSD
int gdataPin = 4;           //GSD

Here is the total code for 8 x 40 array:

//**********************************
//  Name    : Cadaces Driver                         
//  Author  : Bob Davis                                  
//  Date    : 23 February, 2013                                 
//  Version : 1.0                                             
//**********************************
// Pins for the row drivers
int row1Pin = 2;         //R1
int row2Pin = 7;         //R2
int row3Pin = 1;         //R3
int rowEnable = 8;     //REN
int rclockPin = 6;        //RCK
int clockPin = 3;         //SCK
int dataPin = 5;          //RSD
int gdataPin = 4;        //GSD
// Set the pins to output to the sign
void setup() {
  pinMode(row1Pin, OUTPUT);
  pinMode(row2Pin, OUTPUT);
  pinMode(row3Pin, OUTPUT);
  pinMode(rowEnable, OUTPUT);
  pinMode(rclockPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  pinMode(gdataPin, OUTPUT);
}
byte bitmap[][8] = {  //red characters
  {0, 0,0,0,0,0,0,0},
  {0,  4, 10, 17, 17, 31, 17, 17}, //A
  {0, 30, 17, 17, 30, 20, 18, 17}, //R
  {0, 28, 18, 17, 17, 17, 18, 28}, //D
  {0, 0,0,0,0,0,0,0},
  {0, 14, 04, 04, 04, 04, 04, 14}, //I
  {0, 17, 25, 25, 21, 19, 19, 17}, //N
  {0, 14, 17, 17, 17, 17, 17, 14}, //O
  {0, 0,0,0,0,0,0,0},
};
byte gbitmap[][8] = {  //green characters
  {0, 0,0,0,0,0,0,0},
  {0,  4, 10, 17, 17, 31, 17, 17}, //A
  {0, 30, 17, 17, 30, 20, 18, 17}, //R
  {0, 0,0,0,0,0,0,0},
  {0, 17, 17, 17, 17, 17, 17, 14}, //U
  {0, 14, 04, 04, 04, 04, 04, 14}, //I
  {0, 0,0,0,0,0,0,0},
  {0, 14, 17, 17, 17, 17, 17, 14}, //O
  {0, 0,0,0,0,0,0,0},
};
void RunSign(){
  for (int row = 7; row > 0; row--) {
    // turn off display
    digitalWrite(rowEnable, HIGH);
    digitalWrite(rclockPin, LOW);
    // send serial data to display 8 = number of characters
    for (int character = 0; character < 8; character++){
     for (int shiftbit = 5; shiftbit > -1; shiftbit--){
      digitalWrite(gdataPin, LOW);
      digitalWrite(dataPin, LOW);
      if bitRead(gbitmap[character][row],shiftbit) digitalWrite(gdataPin, HIGH);
      if bitRead(bitmap[character][row],shiftbit) digitalWrite(dataPin, HIGH);
      digitalWrite(clockPin, HIGH); digitalWrite(clockPin, LOW);
    } }
    //latch the data
    digitalWrite(rclockPin, HIGH);
    // set up 74138 row selection and turn display back on
    digitalWrite(row1Pin, LOW);
    digitalWrite(row2Pin, LOW);
    digitalWrite(row3Pin, LOW);
    if bitRead(row,0) digitalWrite (row1Pin, HIGH);
    if bitRead(row,1) digitalWrite (row2Pin, HIGH);
    if bitRead(row,2) digitalWrite (row3Pin, HIGH);
    digitalWrite(rowEnable, LOW);
    // Wait to see what we sent to the display ;
    delayMicroseconds(500);
  }
} 

//=== L O O P ===
void loop() {
  RunSign();
}

2 comments:

Howard Bassen said...

This adapter worked nicely on the sign I bought from you on ebay. I hope to learn how to scroll the text using an older example from your blog.

Howard Bassen said...

this worked nicely. I was able to adapt your scrolling 1-color sign code to this adapter and no-solder arduino adapter code.

now I want to make a 3-color scrolling sign (R, Y, G). Which of your codes is the best to modify for this? the 3 color stationary sign or the 1-color single color sign?