Datasheet
WHAT WE’RE DOING:
Parts:
The Internet
THE CIRCUIT:
Schematic
16
CIRC-05
.:8 More LEDs:.
.:74HC595 Shift Register:.
Time to start playing with chips, or integrated circuits (ICs) as they like to
be called. The external packaging of a chip can be very deceptive. For
example, the chip on the Arduino board (a microcontroller) and the one we
will use in this circuit (a shift register) look very similar but are in fact rather
different. The price of the ATMega chip on the Arduino board is a few dollars
while the 74HC595 is a couple dozen cents. It's a good introductory chip, and once you're comfortable playing
around with it and its datasheet (available online http://ardx.org/74HC595 ) the world of chips will be your oyster.
The shift register (also called a serial to parallel converter), will give you an additional 8 outputs (to control LEDs
and the like) using only three Arduino pins. They can also be linked together to give you a nearly unlimited
number of outputs using the same four pins. To use it you “clock in” the data and then lock it in (latch it). To do
this you set the data pin to either HIGH or LOW, pulse the clock, then set the data pin again and pulse the clock
repeating until you have shifted out 8 bits of data. Then you pulse the latch and the 8 bits are transferred to the
shift registers pins. It sounds complicated but is really simple once you get the hang of it.
(for a more in depth look at how a shift register works visit: http://ardx.org/SHIF)
Wire
Shift Register
74HC595
x1
560 Ohm Resistor
Green-Blue-Brown
x8
2 Pin Header
x4
CIRC-05
Breadboard Sheet
x1
Red LED
x8
LED
resistor
(560ohm)
gnd
(ground) (-)
pin
4
pin
3
pin
2
0
1
2
3
4
5
6
7
data
clock
latch
+5V
gnd
74HC595
+5 volts
There is a half moon
cutout, this goes at the top
.:download:.
breadboard layout sheet
http://ardx.org/BBLS05
.:view:.
assembly video
http://ardx.org/VIDE05