(edited) 2006 by tomek ness
for the arduino community <http://www.arduino.cc>
K3 - School of Arts and Communication <http://www.mah.se/k3>
fhp - University of Applied Scien <http://www.design.fh-potsdam.de>
analog multiplexer/demultiplexer------------4051
A multiplexer or demultiplexer enable you to expand the in- and outputs on your Arduino board.
The 4051 is an 8 channel analog multiplexer / demultiplexer, thus:
*If you use the 4051 as a Multiplexer: You can choose between 8 different inputs and
select just one you wane read at the time.
*If you use the 4051 as a Demultiplexer you can choose between 8 different
outputs and select just one you wane write at the time.
Futher more is the 4051 able to work with analog values; in the case of Arduino you are able to
use analog Inputs with a voltage between o-5V and rout them to a AnalogIn Pin on your Arduino.
To select the Pin we would like to read or write, we have to use the three Select Pins (S0, S1
and S2). Each of this pins have to be connected to one digitalOut Pin on the Arduino. Every pin
is representing a number (So = 1; S1 = 2; S2 = 4) and if we set one of this Select pins to HIGH
the curtained number the pin is representing will be transmitted to the 4051. For example:
*If S0 and S1 are HIGH and S2 is LOW pin y3 is selected (1+2+0 = 3).
*If S0 and S2 is HIGH and S1 LOW pin y5 is selected (1+0+4 = 5).
It is not possible to read or write more then one pin on the 4051 at the same time, because you
can just select one pin at the same time. But you can read and write this pins quit fast. There
is no delay needed between selecting and read or writing the pin.
Z ----- common input/output (connected to Arduino Input/Output)
E ----- enable input (active LOW) (connected to ground (gnd))
Vee --- negative supply voltage (connected to ground (gnd))
gnd --- ground (0 V)
S0-S2 - select inputs (connected to three arduino digitalOut Pins)
y0-y7 - independent inputs/outputs
Vcc --- positive supply voltage (5v)
8 Analog Inputs 1 Analog Output
Selected
through 3 digital
Outpins from the arduino
Analog
Inputs
Select Inputs
3 DigitalOutPins
from the arduino
Analog Output
To a AnlogInPin
at the arduino
4051
used as a
Multiplexer
Logic symbol
y3
y4
y5
y0
y1
y2
s0
s1
s2
y6
y7 z
4051
Pin configuration
z
y7
y5
y4
y6
E
Vee
3
4
5
1
2
6
7
14
13
12
16
15
11
10
8 9
y1
y0
y3
Vcc
y2
S0
S1
gnd S2
