Serial to Parallel circuit Shifting Out with 74HC595

  
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Make the following connections: GND (pin 8) to ground, Vcc (pin 16) to 5V OE (pin 13) to ground MR (pin 10) to 5V This set up makes all of the output pins active and addressable all the time. The one flaw of this set up is that you end up with the lights turning on to their last state or something arbitrary every time you first power up the circuit before the program starts to run. You can get around this by controlling the MR and OE pins from your Arduino board too, but this way will work and leave you with more open pins. DS (pin 14) to Ardunio DigitalPin 11 (blue wire) SH_CP (pin 11) to to Ardunio DigitalPin 12 (yellow wire) ST_CP (pin 12) to Ardunio DigitalPin 8 (green wire) From now on those will be refered to as the dataPin, the clockPin and the latchPin respectively. Notice the 0.1`f capacitor on the latchPin, if you have some flicker when the latch pin pulses you can use a capacitor to even it out.
Serial to Parallel circuit Shifting Out with 74HC595 - schematic

3. Add 8 LEDs. In this case you should connect the cathode (short pin) of each LED to a common ground, and the anode (long pin) of each LED to its respective shift register output pin. Using the shift register to supply power like this is called sourcing current. Some shift registers can't source current, they can only do what is called sinking current. If you have one of those it means you will have to flip the direction of the LEDs, putting the anodes directly to power and the cathodes (ground pins) to the shift register outputs. You should check the your specific datasheet if you aren"t using a 595 series chip. Don"t forget to add a 220-ohm resistor in series to protect the LEDs from being overloaded.



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