Review
(^178) The Official Raspberry Pi Projects Book raspberrypi.org/magpi
Add low-
power display
technology to
your Pi Zero
projects!
Pi Supply
Maker
Says
PAPIRUS ZERO MEDIUM
PAPIRUS
any moons ago, we took a
look at the original, full-
size PaPiRus HAT. Now
it’s the turn of its smaller sibling,
designed specifically for use with
the Pi Zero. Unlike conventional
displays, it uses electronic paper
(ePaper) technology to render text
and images, which can remain
on screen without any power
connection for many days before
slowly fading. Obviously, this is
ideal for saving battery power in a
portable project, such as a smart
conference badge. The display is
high contrast and readable even in
bright sunlight.
Like its big brother, the PaPiRus
Zero is supplied in two main
parts: the pHAT board with pre-
soldered female header, and the
screen itself, which is very thin.
Assembly involves inserting the
screen’s mini ribbon cable into
the connector at the side of the
pHAT, then securing the screen to
the board with the double-sided
sticky pads supplied. We tested
out the 2.0-inch Medium display
with 200×96 pixels, but a Small
1.44-inch screen (128×96) is also
available, along with a multi-
screen pack containing both sizes.
With the unit assembled and
mounted on a Pi Zero’s GPIO
equipped with male header (not
supplied), it’s time to install the
software via a single Terminal
command. A second command is
required to set the correct screen
size, then you’re ready to roll.
One of the installed folders
contains a few Python code
examples to get you started,
including a temperature readout
that makes use of the pHAT’s built-
in LM75 temperature sensor. The
Buttons example demonstrates
the use of the pHAT’s five GPIO-
connected buttons. Located along
the top edge, they’re tiny but could
prove useful for switching the info
displayed. Other code examples
include Conway’s Game of Life,
which works well, and a digital
clock. While some minor latency is
noticeable as the numbers change
on the latter, a ‘clear’ command can
be used to wipe the display clean.
The Papirus Python library
includes a write function to
print text strings, which can be
positioned and sized, although it’s
not clear how to change the font.
A draw function displays a one-bit
(black and white) bitmap image.
Handily, the software will convert
most image types automatically.
An ePaper screen for the Raspberry Pi Zero
M
PAPIRUS
HAT
The original
full-size PaPiRus
features a taller
display, up to
2.77 inches
in size. The
same ePaper
technology is
used to render
text and images.
magpi.cc/2ouxPtz
Related
£41 / $54
magpi.cc/2ou5KTh
£30 / $39
Last word
While not suitable for
applications requiring a fast
screen refresh, the PaPiRus
Zero is ideal for saving battery
power in portable projects. The
ePaper display is very easy to
read in all but the lowest light
conditions, from any viewing
angle, and features a decent
110 ppi pixel density.
ZERO MEDIUM