I have not given up on the idea of using an Arduino to power a 120 by 32 LED sign. In fact I have it working, but the Arduino is still not fast enough. The display flickers. I made a quick adapter by taking the old controller and cutting the jacks off the circuit board. Then I soldered a header onto it so that it plugs into the Arduino. Here is what the adapter looks like;
Here is what it looks like when it is working:
Here is the code to make it work. I got rid of the "Shift out" command, each shift clock sends eight bits to the signs eight shift registers. That makes it run much faster.
//**********************************
// Name : 120x32 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
int dataPin1 = 9; //RSD
int gdataPin1 = 10; //GSD
int dataPin2 = 12; //RSD
int gdataPin2 = 11; //GSD
int dataPin3 = 13; //RSD
int gdataPin3 = 14; //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);
pinMode(dataPin1, OUTPUT);
pinMode(gdataPin1, OUTPUT);
pinMode(dataPin2, OUTPUT);
pinMode(gdataPin2, OUTPUT);
pinMode(dataPin3, OUTPUT);
pinMode(gdataPin3, OUTPUT);
}
//=== Character Array ===
// Characters are A, B, C, etc. Only upper case.
byte alphabets[][8] = {
{0, 04, 10, 17, 17, 31, 17, 17}, //A
{0, 30, 17, 17, 30, 17, 17, 30}, //B
{0, 14, 17, 16, 16, 16, 17, 14}, //C
{0, 28, 18, 17, 17, 17, 18, 28}, //D
{0, 31, 16, 16, 31, 16, 16, 31}, //E
{0, 31, 16, 16, 31, 16, 16, 16}, //F
{0, 14, 17, 16, 16, 19, 17, 14}, //G
{0, 17, 17, 17, 31, 17, 17, 17}, //H
{0, 14, 04, 04, 04, 04, 04, 14}, //I
{0, 07, 02, 02, 02, 02, 10, 14}, //J
{0, 17, 18, 20, 24, 20, 18, 17}, //K
{0, 16, 16, 16, 16, 16, 16, 31}, //L
{0, 10, 21, 21, 21, 17, 17, 17}, //M
{0, 17, 25, 25, 21, 19, 19, 17}, //N
{0, 14, 17, 17, 17, 17, 17, 14}, //O
{0, 30, 17, 17, 30, 16, 16, 16}, //P
{0, 14, 17, 17, 17, 17, 19, 15}, //Q
{0, 30, 17, 17, 30, 20, 18, 17}, //R
{0, 14, 17, 16, 14, 01, 17, 14}, //S
{0, 31, 04, 04, 04, 04, 04, 04}, //T
{0, 17, 17, 17, 17, 17, 17, 14}, //U
{0, 17, 17, 17, 10, 10, 10, 04}, //V
{0, 17, 17, 17, 21, 21, 21, 10}, //W
{0, 17, 17, 10, 04, 10, 17, 17}, //X
{0, 17, 10, 10, 04, 04, 04, 04}, //Y
{0, 31, 8, 04, 02, 04, 8, 31}, //Z
{0, 0, 21, 14, 31, 14, 21, 0}, //*
};
byte numbers[][8] = {
{0, 04, 12, 04, 04, 04, 04, 14}, //1
{0, 14, 17, 01, 02, 04, 8, 31}, //2
{0, 14, 01, 01, 06, 01, 01, 14}, //3
{0, 17, 17, 17, 31, 01, 01, 01}, //4
{0, 31, 16, 16, 14, 01, 17, 14}, //5
{0, 14, 16, 16, 30, 17, 17, 14}, //6
{0, 31, 01, 01, 02, 04, 8, 16}, //7
{0, 14, 17, 17, 14, 17, 17, 14}, //8
{0, 14, 17, 17, 15, 01, 01, 01}, //9
{0, 14, 17, 17, 17, 17, 17, 14}, //0
};
byte bitmap[][8] = { //red characters
{0, 0,0,0,0,0,0,0},
{0, 04, 12, 04, 04, 04, 04, 14}, //1
{0, 14, 17, 01, 02, 04, 8, 31}, //2
{0, 14, 17, 17, 17, 17, 17, 14}, //0
{0, 17, 17, 10, 04, 10, 17, 17}, //X
{0, 14, 01, 01, 06, 01, 01, 14}, //3
{0, 14, 17, 01, 02, 04, 8, 31}, //2
{0, 0,0,0,0,0,0,0},
{0, 4, 10, 17, 17, 31, 17, 17}, //A
{0, 0,0,0,0,0,0,0},
{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},
{0, 14, 17, 16, 14, 01, 17, 14}, //S
{0, 14, 04, 04, 04, 04, 04, 14}, //I
{0, 14, 17, 16, 16, 19, 17, 14}, //G
{0, 17, 25, 25, 21, 19, 19, 17}, //N
{0, 0,0,0,0,0,0,0},
};
byte gbitmap[][8] = { //green characters
{0, 0,0,0,0,0,0,0},
{0, 04, 12, 04, 04, 04, 04, 14}, //1
{0, 14, 17, 01, 02, 04, 8, 31}, //2
{0, 14, 17, 17, 17, 17, 17, 14}, //0
{0, 17, 17, 10, 04, 10, 17, 17}, //X
{0, 14, 01, 01, 06, 01, 01, 14}, //3
{0, 14, 17, 01, 02, 04, 8, 31}, //2
{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},
{0, 14, 17, 16, 14, 01, 17, 14}, //S
{0, 14, 04, 04, 04, 04, 04, 14}, //I
{0, 14, 17, 16, 16, 19, 17, 14}, //G
{0, 17, 25, 25, 21, 19, 19, 17}, //N
{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 20 = number of characters
for (int character = 0; character < 21; character++){
for (int shiftbit = 5; shiftbit > -1; shiftbit--){
digitalWrite(gdataPin, LOW);
digitalWrite(dataPin, LOW);
digitalWrite(gdataPin1, LOW);
digitalWrite(dataPin1, LOW);
digitalWrite(gdataPin2, LOW);
digitalWrite(dataPin2, LOW);
digitalWrite(gdataPin3, LOW);
digitalWrite(dataPin3, LOW);
if bitRead(gbitmap[character][row],shiftbit) digitalWrite(gdataPin, HIGH);
if bitRead(bitmap[character][row],shiftbit) digitalWrite(dataPin, HIGH);
if bitRead(gbitmap[character][row],shiftbit) digitalWrite(gdataPin1, HIGH);
if bitRead(bitmap[character][row],shiftbit) digitalWrite(dataPin1, HIGH);
if bitRead(gbitmap[character][row],shiftbit) digitalWrite(gdataPin2, HIGH);
if bitRead(bitmap[character][row],shiftbit) digitalWrite(dataPin2, HIGH);
if bitRead(gbitmap[character][row],shiftbit) digitalWrite(gdataPin3, HIGH);
if bitRead(bitmap[character][row],shiftbit) digitalWrite(dataPin3, HIGH);
digitalWrite(clockPin, HIGH);
digitalWrite(clockPin, LOW);
} }
//latch the data
digitalWrite(rclockPin, HIGH);
// set up 74138 row sesection 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();
}
