Collin's Lab: Digital to Analog Converter

The Digital to Analog Converter (DAC) turns bits into waves using a surprisingly simple circuit built from little more than a few resistors. Learn how to build your own R-2R DAC and use it to generate waveforms with a microcontroller

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computers speak in digital binary
language a series of high and low
voltages represented by ones and zeros
in order for a computer to recreate
something like a continuous analog sound
wave it needs a little help
the aptly named digital-to-analog
converter performed that service quite
well
converting a series of digital on/off
messages into specific voltage levels
most digital-to-analog converters come
in
chip form but you can actually make your
own using just some resistors
allow me to demonstrate just like binary
data the pins on a programmable
microcontroller can be set high or low 0
or 5 volts on most boards
but by simply adding two resistors and a
connection to ground we create a voltage
divider capable of lowering the output
voltage to a point between 0 and 5 volts
determined by the resistor values we use
to build on this idea we can link
multiple pins together in a sort of
resistor ladder where they can be used
in combination to create a wider range
of output voltages each pins position on
the ladder determines how much of its
original five volts will reach the
output this arrangement is called an R
to R deck because it uses one resistor
value 10k in this case and a second
resistor value two times that amount by
extending the letter to more output pins
we increase our Dax resolution each pin
can use one binary bit to specify its
higher low status
so with eight pins are deck will have an
8-bit resolution
just like the good old days to make
programming a bit easier we can store
those eight bits together as a bite
to make things even simpler we can
specify a byte value using good
old-fashioned numbers any whole number
from 0 on up to 255 can be stored as an
8-bit binary bite by writing that number
two are back pins
it will be translated into a value
between 0 and 5 volts which is pretty
slick
I assembled my R to R deck on a
breadboard using an Arduino Nano my car
controller hook the dax output up to my
oscilloscope and audio monitor and last
but not least loaded up a bit of example
code if we provide our microcontroller
with a list of values to write out to
the deck in a loop we can create
waveforms likes a sine wave
and essentially that's how that works
Dex pretty awesome no to learn how to
pump for your deck and various other
interesting things
head over to make seen . comment