Hi LMR. After stumbling onto this site last month I fell in love with the idea robotics. I bought a Arduino starter kit last week, to start learning the basics. One of the tutorials I did involved counting in binary using a shift register and 8 LEDs. I didn't really understand the code for the tutorial or how the shift operator works so I started with something more basic.
So far using the shift register, I can control the LEDs individually, use loops to make the LEDs cycle through and do night rider effect. Now i'm trying to use bitwise operators to get the same cycling effect as I did with regular loops. I almost have it but my last LED is being skipped. I did some troubleshooting and I think its because the counter is being reset before the 128bit led is turning on. I just can't seem fix it. Below is my code. If knows how i can fix this it would be appreciated :)
// Pin Variables
int data = 2;
int clock = 3;
int latch = 4;
// Variable to represent LEDs' states
byte LED = 1;
// Pot variables
int potPin = 0;
int potVal = 0;
// Pin initialization & Serial start
void setup()
{
Serial.begin(9600);
pinMode(data, OUTPUT);
pinMode(clock, OUTPUT);
pinMode(latch, OUTPUT);
}
void loop()
{
digitalWrite(latch, LOW); // Set latch low so data can be written
// Resets LED states once last LED has be turned on.
if (LED >= 128)
LED = 1;
// Loops for all 8 bits
for (int i = 0; i < 8 ; i ++)
{
if(LED & (1 << (i)))
{
digitalWrite(data, HIGH);
Serial.print(1);
}
else
{
digitalWrite(data, LOW);
Serial.print(0);
}
digitalWrite(clock, HIGH); // Load bit(i)
delay(5);
digitalWrite(clock, LOW);
}
LED = (LED << 1); // binary offset by 1 to the left
Oh well, a bit more help than: Your loop can be summarized like this (always make these when coding something bigger than a blinky LED).
reset pattern if it equals 10000000 show pattern shift pattern
You could write that in full, since it repeats only eight seven times. Let’s include the bit patterns.
pattern = 00000001 show pattern = 00000001 shift pattern show pattern = 00000010 shift pattern show pattern = 00000100 shift pattern show pattern = 00001000 shift pattern show pattern = 00001000 shift pattern show pattern = 00010000 shift pattern show pattern = 00100000 shift pattern show pattern = 01000000 shift pattern show pattern = 10000000 nah let’s reset the pattern instead
Now let’s see what happens when we did not have a reset condition: … (as above) show pattern = 01000000 shift pattern show pattern = 10000000 shift pattern show pattern = 00000000 shift pattern show pattern = 00000000 shift pattern … (ad infinitum)
I suggest you change that reset condition. This means you may have to preset (PPPPreset!) your initial pattern with something (different).
%0000 0000 = 0 (I added a space to separate the nybbles) %0000 0001 = 1 %0000 0010 = 2 %0000 0100 = 4 %0000 1000 = 8 %0001 0000 = 16 %0001 0000 = 32 %0100 0000 = 64 %1000 0000 = 128
127 decimal would be %0111 1111
Yes one byte (usually) has 8 bits. Make sure to use a byte type variable. A word type variable (usually) has twice the number of bits. This means that shifting a word with value 128 (to the left) will result in a value 256 instead of 0.
I must have misunderstood what you were saying. … And that NEVER happens to me. I will go sit in the corner now and offer knowledgeable information when I have it.
Thanks for the help guys. I finally got it working last night. I’m pretty busy with finals at university right now so I only get to tinker during study breaks
I will go sit in the corner now and offer knowledgeable information when I have it.