Hello Arduino users!
First i want to say, the Arduino project is awesome! Prototyping with low costs 
Now my question, i have 16 stepper motor's and a Arduino UNO. Now i want to control the stepper motors with my code. But i have some strange problems what i cant figure out... I have used this tutorial with a dual shiftregister. And i replaced the last 8 LED's for 8 stepper motor's (from the floppydrivepin's).
So:
The first register have 6 LED's
The second register have 6 stepper motor's (it have it's own power supply)
It works, but when the first stepper motor should step all leds fell out, i think it is because it uses its own powersupply.
Here's my code i use:
const int pinLatch = 8; // Connect to ST_CP of 74HC595
const int pinClock = 12; // Connect to SH_CP of 74HC595
const int pinData = 11; // Connect to DS of 74HC595
unsigned long registerState = 0;
// First load
void setup()
{
Serial.begin(9600);
pinMode(pinLatch, OUTPUT);
pinMode(pinClock, OUTPUT);
pinMode(pinData, OUTPUT);
}
// Call on crystal (16MHz)
void loop()
{
for(int x=0; x<16; x++)
writeRegister(x, 1);
delay(500);
for(int x=0; x<16; x++)
writeRegister(x, 0);
delay(500);
}
void writeRegister(int pinNumber, int pinState)
{
digitalWrite(pinLatch, LOW);
bitWrite(registerState, pinNumber, pinState);
byte shiftRegister[2];
shiftRegister[0] = registerState;
shiftRegister[1] = registerState >> 8;
shiftOut(pinData, pinClock, MSBFIRST, shiftRegister[1]);
shiftOut(pinData, pinClock, MSBFIRST, shiftRegister[0]);
digitalWrite(pinLatch, HIGH);
delay(100); // <- I use for testing...
}
