Custom PC - UK (2019-12)

W

henbuildinga self-contained

RaspberryPiproject,there’s

alwaysthequestionofhowto

displayitsdata.A traditionalLCDpanelisa

colourfuloption,butdrawsa lotofpowerand

glowsbrightlyattimesyoumightnotwantto

bedisturbed.AnOLEDdisplayiscompact

andeye-catching,buta littlecramped.

Meanwhile,devicessuchasthePimoroni

UnicornHATanditsHDupgradeareneat

andcolourful,butlacktheresolutionforany

displaybeyondsimpleicons.

TheInkywHAT,meanwhile,comesrather

outofleftfield.BasedonanE-Inkdisplay,

andbuildingontheearlierInkypHATdisplays

fortheRaspberryPiZerorange,the

oversizedadd-onboard– the‘w’standsfor

‘wide’– addsa 4.2indisplaypanelviaa

solderlessconnectiontoanyPi’spopulated

GPIOheader.

Thedisplayisreasonablysized,butalso

relativelylow-resolutionat 400 by 300

pixels.Inthebasemodel,anyoneofthese

pixelscanbeblackorwhite– theblackbeing

a verydarkgreyandthewhitebeinga very

lightgrey,asisusuallythecasefore-paper

styledisplays.Twoupgradedvariantsadda

infrequentlyupdateddataina friendlymanner.

Bundledexamples,writteninPythonasis

usualforPimoroniproducts,showcase

displayingcalendarinformation,famous

quotations,orevenusingoneasanoversized

namebadge.

Witha littlehacking,it’spossibletocrama lot

ofinformationonthescreentoo.Usingthe

freeTomThumbfontdesignedbyRobey,with

tiny4 x 6 characters,youcancramupto 80

horizontalcharactersand 42 linesontothe

display– a totalof3,360characters– while

stillbeingentirelyreadable.

TheonlydownsideoftheInkywHAT,for

anyonewhodoesn’tneedfullcolour or

animationatleast,is theprice.E-Ink displays

aren’tcheap,andPimoroni’sHAThardware

bumpsupthepriceto£42.50forthe black

andwhiteversions,or£49.50forthe three-

colourvariants(bothincVAT).Forthe money,

youdogetmountinghardware,a booster

headerforsolder-freeinstallation, and a board

thatbreaksoutGPIOpinstoprovide access to

thePi’sI²CandSPIbuses,aswellas a single

general-purposepin,3V3,and5Vpins and a

groundpin.TheInkywHATis available now

frompimoroni.com

CUSTOMISATION / HOBBY TECH

REVIEW

Pimoroni Inky wHAT

third colour

into the mix –

red or yellow,

depending on

the model.

E-Ink and

other e-paper

displays, knownas

electrophoretic

displays, are typically

found in e-readers.

They work by floating

or sinking colouredballs

dependingoncharge;

unlikeanLCD,thedisplay

maintainsitscontentseven

whenpoweredoff.

Theresultisa panelthatdrawsverylittle

powerandreliesonreflectedlight.Whilethat

meansit’sreadableinbrightsunlight,unlikea

typicalLCD,it’salsoimpossibletoreadinthe

dark,whichmaybea blessingora curse,

dependingonyourproject.E-Inkdisplaysare

allabouttrade-offs.Ingoodlightingthey’re

incrediblyclear,butinpoorlightingthey’re

unreadable.Theydon’tneedongoingpower

tomaintainanimage,buttheytakea

surprisinglylongtimetorefreshthatimage.

Theslow-refreshissuecanbeseeninthe

InkywHATinspades.Whiletheblackand

whitemodel– and

thethree-colour

models, when run

in black and white

mode – refresh in

six or so seconds of

flashing and blinking,

refreshing a display

running in three-

colour mode takes

around 30 seconds.

It’s not for

animation then.

Where the Inky wHAT

excels is displaying

Gareth Halfacree is the news reporter at http://www.bit-tech.net, and a keen computer hobbyist who likes to tinker with technology. @ghalfacree

The Inky wHAT offers a surprisingly large,

though relatively low-resolution, E-Ink

display for any Raspberry Pi

The 400 x 300 resolution is low and individual

pixels are clearly visible if you look closely, but

it’s enough for a lot of projects