3

FIELD TEST

Both displays have great tutorials and source
code for using them with your Raspberry Pi. The
Adafruit Bicolor LED Square Pixel Matrix also
includes a library to make it easy to use with an
Arduino. And both displays have plenty of well-
documented projects that you can find online from
a simple search.
One other thing you should be aware of with
these boards is that when scrolling text or a symbol,
the spacing of the pixels on the Micro Dot pHAT can
make it a little more difficult to read compared to the
Adafruit Pixel Matrix. If you aren’t planning on doing
any scrolling, then it’s really not an issue. And if you
still want the look of the Micro Dot pHAT, we found
that you just need to scroll the letters a little slower
compared to other LED matrices and it does just
fine. You could also diffuse the pixels a bit by adding
a translucent piece of plastic [gasp!], but that would
completely kill the beautiful aesthetics of the Micro
Dot’s segments.

At the end of the day, both of these displays

are really nice, but we give the edge to the

Adafruit Bicolor LED Square Pixel Matrix since it is

compatible with more microcontrollers and has the

capability to display three colours. Yes three, not

two as you might think, since you can display both

red and green LEDs at the same time, giving you

an orange glow. It was a really close call since they

both function so well and are so easy to implement.

Which one you choose really boils down to what

you need for your project. If you really want a

beautiful-looking display, even when it’s powered

down, choose the Micro Dot pHAT. The ability to

see the connections of each segment is really

beautiful. If you need multiple colours in one

display, or if you want to animate or scroll letters

or simple graphics, pick up the Adafruit Bi-Color

Matrix. Or better yet, neither one is too expensive,

so do yourself a favour and add both of them to

your lab, you won’t regret it.

Far Left

Adafruit’s bicolour

display is ideal for

creating a retro look

for your project

Credit

Adafruit licensed

under CC

Left

A bit more

challenging to work

with, but the look of

a Nixie tube is hard

to match

Credit

Hiroyuki Takeda

licensed under CC

BY-ND 2.0

Micro Dot pHAT

Amazingly

beautiful

retro fun from

all angles.

Bicolor Backpack

When you need

a retro-looking

display with

more than one

colour, this

bicolour matrix

is perfect.

8

9

/ 10

/ 10

VERDICT

NIXIE TUBES

AFTER ALL THESE YEARS

The 1950s were an amazing time when it came to

innovation, from the invention of the first solar cell

and hovercraft, to the modern plastic hula hoop and

integrated circuit. It was also in the 1950s that the

Nixie tubes were manufactured by the Haydu Brothers

Laboratories. And although you may have thought this

technology would have disappeared with all the modern

displays available, you’d be wrong – at least it’s still

going strong within the electronic hobbyist community.

Nixie tubes typically consist of ten cathodes in the

shapes of numbers 0-9 that emit a beautiful glow when

about 150–200 volts are applied. It’s a fairly simple

technology to understand, but take one look at the

workings and you will quickly see that they are a small

marvel of manufacturing. If you want the ultimate in

retro-chic for your next project, look into Nixie tubes –

just be careful when using such high voltages!

The Adafruit Bicolor LED

Square Pixel Matrix also

includes a library to

make it easy to use with

an Arduino

”

”