Of marque lights and shift registers

Projects Programming
1

We are putting together a little maker space and the main guy asked me to get his marque lights working.
There are 8 LEDs in each letter and 6 letters make up the word MAKERS.
I used adafruit"s lesson 4: "eight LEDs and a shift register to wire the shift registers and tested each letter separately.
The goal for now is to get the first letter M to scroll while the others letters stay off. one light, then two, then three as they chase each other around until they all eight are lit up.
Problem I'm having is the first LED in the M lights up, call it M1. Then the first LED in the A lights up A1. This continues until almost all the lights are lit up on both letters. I say almost because M8 lights up and then A goes out instead of lighting A8.
I can't seem to keep the second letter from lighting up.

Here's the program I wrote for it:

//Pin connected to ST_CP of 74HC595
int latchPin = 5;
//Pin connected to SH_CP of 74HC595
int clockPin = 6;
////Pin connected to DS of 74HC595
int dataPin = 4;
byte lets[] = {
  B00100000, B00110000, B00111000, B00111100, B00111110, B00111111               };
byte leds[] = {
  B00000001, B00000011, B00000111, B00001111, B00011111, B00111111, B01111111, B11111111       };
int n = 0;


void setup() {
  //Start Serial for debuging purposes	
  Serial.begin(9600);
  //set pins to output because they are addressed in the main loop
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
}

void loop() {
  digitalWrite(latchPin, LOW);
  for (int z = 0; z < 5; z++)
  {
    delay(1000);      
    shiftOut(dataPin, clockPin, LSBFIRST, 0);
    Serial.print("z");
    Serial.print(z);
  }
  //digitalWrite(latchPin, HIGH);
   //digitalWrite(latchPin, LOW);
   delay(1000);
  shiftOut(dataPin, clockPin, LSBFIRST, leds[n]);
  //delay(5000); //put here M on 1 sec both on 10 secs
  digitalWrite(latchPin, HIGH);
  delay(5000); //put here 5 seconds between M and A
               //then both on 5
               // until M7 when A doesn't come on
   Serial.print(" n");
  Serial.println (n);
   //light (n);
  n++;
  if (n > 7) 
  {
    n = 0;
  }
 } // end of loop
 
 // serial monitor results:
 //   z0z1z2z3z4 n0
 //   z0z1z2z3z4 n1
 //   z0z1z2z3z4 n2
 //   z0z1z2z3z4 n3
 //   z0z1z2z3z4 n4
 //   z0z1z2z3z4 n5
 //   z0z1z2z3z4 n6
 //   z0z1z2z3z4 n7
 //   z0z1z2z3z4 n0
 //   z0z1z2z3z4 n1
 //   z0z1z2z3z4 n2
 //   z0z1z2z3z4 n3
 //   z0z1z2z3z4 n4
 //   z0z1z2z3z4 n5
 //   z0z1z2z3z4 n6
 //   z0z1z2z3z4 n7

The serial results seem fine. See anything I did wrong?

2 
  for (int z = 0; z < 5; z++)
  {
    delay(1000);     
    shiftOut(dataPin, clockPin, LSBFIRST, 0);
    Serial.print("z");
    Serial.print(z);
  }

Why do you need to shift 0 out 5 times?

3

I shift 5 zeros so the AKERS letters don't light up.
Then I send the desired value for M.
But somehow the A pretty much follows what the M is doing.

I changed it to 6 and it didn't change anything.

edit: Oh yeah, thanks for the reply.

4

So it's not just me that can't figure out what's going on?

5

It's difficult for me to picture how your project is wired and how that relates to the code. The first two values of the leds array are B00000001 and B00000011. So is B00000001 the first LED in "M" and B00000011 the first LED in "M" plus the first LED in "A"?

What does the z = 0 to 4 loop do?

6

Hey thanks for the reply.
Here's a link to the adafruit lesson I used to wire it up:

The plan with the "leds" array is that each 1 equals an LED that turns on. So the for loop is supposed to pass some zeros through the shift registers so the AKERS are 0 or all off, then the leds array value gets passed to the M.

This was especially confusing for me when I was trying to get the first letter to scroll then stay on while the second scrolled and the rest stayed off. The goal is to get the lights to turn on and stay on, scroll from the first LED in the M to the last LED in the S.
I might have to set a different goal.

I can't remember what happens when I only pass 4 zeros. I'll change the for loop to 4 and 6 passes then let you know what happens.
The serial result at the bottom of the code is doing what I want. 5 zeros then an array value goes to the M.