Practical Electronics - August 2022

78 Pages·2022·16 MB·English

Practical
EElleeccttrroonniiccss
The UK’s premier electronics and computing maker magazine
Circuit Surgery KickStart Make it with Micromite
Using distortion and Exploring DACs and MMBASIC + RPi Pico + display
distortion circuits microcontrollers = PicoMite Backpack!
WIN!
Microchip
SAM V71
XXppllaaiinneedd UUllttrraa
Multi-purpose Battery Evaluation Kit
WIN!
Manager
Retro gaming
with Nano Pong!
FFlloowwccooddee
DDDiiigggiiitttaaalll CCCllloooccckkk
DDDeeesssiiigggnnn
Simple
Flowcode
MIDI C
void interrupt(void)
{ if (intcon & 4)
{ Assembly
Music cFol(Ce);aMr__IbNitT(iEntRcoRnU, P2T);_TMR mbsof vSlwTA DT′U7′S, RP0
bcf STATUS, RP1 Hex
movwf _adcon1
Keyboard mmoovvwlwf D_o′1p9ti2o′n_reg ::00480000000800008FA000011F20208S30730
EF10000
:10001000040EF2000A0
EF300BA110A122928352
86C
:2000200D928FE28073
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Net Work – The irresistible rise of automotive electronics
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microchip.com/PIC16F180 MEC2423A-UK-05-22
Practical Volume 51. No. 8
August 2022
ISSN 2632 573X
Electronics
Contents
Projects and Circuits
Multi-purpose Battery Manager by Tim Blythman 14
(cid:37)uilding on our recent (cid:37)attery (cid:48)ulti (cid:47)ogger(cid:15) this design not only (cid:80)onitors (cid:90)hat(cid:183)s
going on but also connects and disconnects loads based on battery charge state.
Simple MIDI Music Keyboard by Tim Blythman 26
(cid:55)his (cid:48)(cid:44)(cid:39)(cid:44) (cid:46)ey(cid:69)oard is a (cid:73)ollo(cid:90)(cid:16)u(cid:83) to our (cid:25)(cid:23)(cid:16)(cid:78)ey (cid:48)(cid:44)(cid:39)(cid:44) (cid:48)atri(cid:91). (cid:44)t is (cid:77)ust as (cid:193) e(cid:91)i(cid:69)le and
offers an easy way to make music, plus it can be repurposed for many other uses.
Nano Pong by Tim Blythman 30
Our Nano Pong game is modern and retro at the same time; it replaces the
70-odd discrete logic chips in the original with a single chip that costs about £1!
USB Power Delivery Chargers by Jim Rowe 36
Learn about low-cost modules that have appeared recently to take advantage of the
dramatic growth in USB capability, especially in the area of power delivery (PD).
Series, Features and Columns
Techno Talkby Mark Nelson 8
Time for a total rethink?
Net Work by Alan Winstanley 10
A round-up of topical technological issues and trends from the UK and
Flowcode around the world.
Make it with Micromite by Phil Boyce 40
C Part 38: How to build a PicoMite BackPack
void interrupt(void)
{ if (intcon & 4)
{ Assembly KickStart by Mike Tooley 47
clear_bit(intcon, 2);
Fo(C);M_INTERRUPT_TMR mbsof vSlwTA DT′7U′S, RP0 Part 9: Exploring microcontroller digital-to-analogue conversion
bcf STATUS, RP1 Hex
mmmooovvvlwwwff D__ao′1dp9cti2oo′nn1_reg ::E00F48100000000008000008FA000011F20208S30730 (cid:48)Flaas(cid:91)h(cid:183)sin Cg oLoElD (cid:37)se aannds d(cid:67)ryo o(cid:46)linagx eTnhgei n(cid:46)eaegrsn i–fi cPeanrtt 30 54
:10001000040EF2000A0
EF300BA110A122928352
86C Flowcode Graphical Programmingby Martin Whitlock 58
:2000200D928FE28073
Part 5: Building a Digital Clock
Circuit Surgery by Ian Bell 65
Distortion and distortion circuits – Part 3
Regulars and Services
Wireless for the Warrior 2
Subscribe to Practical Electronics and save money 4
Reader services – Editorial and Advertising Departments 7
Editorial 7
The power of batteries
Exclusive Microchip reader offer 9
Win a Microchip SAM V71 Xplained Ultra Evaluation Kit
PE Teach-In 8 25
Practical Electronics PCB Service 70
PCBs for Practical Electronics projects
Classifi ed ads and Advertiser inde(cid:91) (cid:26)(cid:20)
Next month! – highlights of our next issue of Practical Electronics 72
MMaaddee iinn tthhee UUKK..
Written in Britain, Australia,
the US and Ireland.
Read everywhere.
© Electron Publishing Limited 2022
Copyright in all drawings, photographs, articles,
technical designs, software and intellectual property
published in Practical Electronics is fully protected,
and reproduction or imitation in whole or in part are
expressly forbidden.
The September 2022 issue of Practical Electronics will
be published on Thursday, 4 August 2022 – see page 72.
Practical Electronics | August | 2022 1
WIRELESS FOR
THE WARRIOR
by LOUIS MEULSTEE
THE DEFINITIVE TECHNICAL HISTORY OF RADIO
COMMUNICATION EQUIPMENT IN THE BRITISH ARMY
The Wireless for the Warrior books are timeframe saw the introduction of VHF FM
a source of reference for the history and and hermetically sealed equipment.
development of radio communication
equipment used by the British Army from the Volume 3 covers army receivers from 1932 to
very early days of wireless up to the 1960s. the late 1960s. The book not only describes
receivers specifi cally designed for the British
The books are very detailed and include Army, but also the Royal Navy and RAF. Also
circuit diagrams, technical specifi cations covered: special receivers, direction fi nding
and alignment data, technical development receivers, Canadian and Australian Army
history, complete station lists and vehicle receivers, commercial receivers adopted by the
fi tting instructions. Army, and Army Welfare broadcast receivers.
Volume 1 and Volume 2 cover transmitters Volume 4 covers clandestine, agent or ‘spy’
and transceivers used between 1932-1948. radio equipment, sets which were used by
An era that starts with positive steps special forces, partisans, resistance, ‘stay
taken to formulate and develop a new behind’ organisations, Australian Coast
series of wireless sets that offered great Watchers and the diplomatic service. Plus,
improvements over obsolete World War I selected associated power sources, RDF and
pattern equipment. The other end of this intercept receivers, bugs and radar beacons.
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Practical Volume 51. No. 8
August 2022
ISSN 2632 573X
Electronics
Editorial
Editorial offi ces
Practical Electronics Tel [phone] The power of batteries
Electron Publishing Limited Mob [phone]
1 Buckingham Road Fax [phone] We have a great set of projects for you this month. An easy-to-
Brighton Email [email protected]
East Sussex BN1 3RA Web www.electronpublishing.com build MIDI keyboard; Nano Pong, a modern twist on a retro game;
and a PicoMite Backpack that combines the power of MMBasic,
Advertisement offi ces a high-quality touchscreen display and an inexpensive but very
Practical Electronics Adverts Tel [phone] capable Raspberry Pi Pico microcontroller. But that’s not all –
1 Buckingham Road Mob [phone]
Brighton Email [email protected] my favourite in this issue is a very useful Battery Manager that
East Sussex BN1 3RA combines three recent projects (Battery Multi-logger, Battery
Balancer, and a Mini Isolated Serial Link) with some new circuits
Editor Matt Pulzer
to produce a handy design that is compact, fl exible and modular.
General Manager Louisa Pulzer
Digital subscriptions Stewart Kearn Tel [phone] It can connect and disconnect up to four loads/sources to protect
Online Editor Alan Winstanley batteries, and is capable of switching well over 20A at 10V-60V.
Web Systems Kris Thain
If you’re in the market for battery charging designs that go above
Publisher Matt Pulzer
and beyond basic ‘electron pumping’ then this is one for you.
Print subscriptions
Practical Electronics Subscriptions Back in the early days of PE, most battery circuits really only
PO Box 6337
meant one thing, some variation on a simple lead-acid battery
Bournemouth BH1 9EH Tel [phone]
United Kingdom Email [email protected] charger. They were relatively crude, mostly safe and worked
reasonably well, but there wasn’t a lot of sophistication built into
Technical enquiries
the designs.
We regret technical enquiries cannot be answered over the
telephone. We are unable to offer any advice on the use, purchase,
re(cid:83)air or (cid:80)odifi cation o(cid:73) co(cid:80)(cid:80)ercial e(cid:84)ui(cid:83)(cid:80)ent or the incor(cid:83)oration Fast forward to 2022 and the range of battery technologies, cell
or (cid:80)odifi cation o(cid:73) designs (cid:83)u(cid:69)lished in the (cid:80)aga(cid:93)ine. (cid:58)e cannot designs and supporting circuity is huge. Power density and
provide data or answer queries on articles or projects that are
charge time have improved in leaps and bounds, but so too has
(cid:80)ore than fi ve years old.
the need to charge/discharge properly – get that wrong and at best
Questions about articles or projects should be sent to the editor you will damage a cell, at worst it may catch fi re. Lithium-based
by email: [email protected]
batteries have become the cornerstone of many technologies
Projects and circuits that run untethered from the mains, from in-ear headphones to
All reasonable precautions are taken to ensure that the advice and electric vehicles, but they are very picky about how you use them
data given to readers is reliable. We cannot, however, guarantee and do not tolerate abuse.
it and we cannot accept legal responsibility for it.
A number of projects and circuits published in Practical Electronics As the world moves away from fossil fuels and towards
employ voltages that can be lethal. You should not build, test, distributed generation systems (photovoltaic panels or wind
modify or renovate any item of mains-powered equipment unless
turbines) and electric transport expands to include everything
you fully understand the safety aspects involved and you use an
RCD (GFCI) adaptor. from scooters to fl ying taxis, modern batteries are going to
become ever more important. Having the right circuit designs and
Component supplies knowhow will be vital, and I hope you enjoy reading about, or
We do not supply electronic components or kits for building the
even building, this month’s Battery Manager.
projects featured, these can be supplied by advertisers. We
advise readers to check that all parts are still available before
commencing any project in a back-dated issue. Matt Pulzer
Publisher
Advertisements
Although the proprietors and staff of Practical Electronics take
reasonable precautions to protect the interests of readers by
ensuring as (cid:73)ar as (cid:83)ractica(cid:69)le that advertise(cid:80)ents are (cid:69)ona fi de(cid:15)
the magazine and its publishers cannot give any undertakings
in respect of statements or claims made by advertisers, whether
these advertisements are printed as part of the magazine, or in
inserts. The Publishers regret that under no circumstances will
the magazine accept liability for non-receipt of goods ordered, or
for late delivery, or for faults in manufacture.
Transmitters/bugs/telephone equipment
We advise readers that certain items of radio transmitting and
telephone equipment which may be advertised in our pages
cannot be legally used in the UK. Readers should check the law
(cid:69)e(cid:73)ore (cid:69)uying any trans(cid:80)itting or tele(cid:83)hone e(cid:84)ui(cid:83)(cid:80)ent(cid:15) as a fi ne(cid:15)
confi scation o(cid:73) e(cid:84)ui(cid:83)(cid:80)ent and(cid:18)or i(cid:80)(cid:83)rison(cid:80)ent can result (cid:73)ro(cid:80)
illegal use or ownership. The laws vary from country to country;
readers should check local laws.
Practical Electronics | August | 2022 7
Time for a Techno Talk
total rethink?
Mark Nelson
The way we have electric power delivered to our homes – and the method in which we consume it –
needs to be reconsidered. It’s ineffi cient and no longer rational says one think tank. So, what are we
doing wrong, and why should we change?
I’m going to hazard a guess. the Green Lib Dems, which functions practice positively therapeutic. What’s
If you are reading this article at home as an environmental think tank for the more, I make no secret of this shame-
in the UK, then I can say with near Liberal Democrat party. You can read less pleasure.
certainty that your domestic electric- full details of the proposal, which was If you are not a sodderer, watch https://
ity supply is delivered as alternating published last November, at: https://bit. youtu.be/BnbcTtMptkU where you’ll
current (AC) at not far off 230 volts. ly/pe-aug22-acdc rapidly discover that soddering is how
Conveniently, your light fi ttings and In a nutshell, it argues that according many Americans pronounce (and spell)
electrical appliances are designed for a to the Committee on Climate Change, the word soldering. Alternatively, just
corresponding 230V AC supply, making the UK will need a quadrupling of our consult www.Urbandictionary.com,
for an extremely harmonious setup. But electrical supply capacity to support which pompously defi nes the word as
is this ideal? Is it even logical? electrification of heating and trans- an incorrect term for ‘soldering’, usually
port. This in turn will require a huge used by idiots and people with ‘labtop’
Horses for courses investment in new power distribution computers. I was certainly confused back
Fifty or even fewer years ago the an- infrastructure, which offers a once-in- in the 1970s when hobby electronics
swer was undoubtedly yes. After all, a-hundred-year opportunity to replace shops began selling small plastic con-
your appliances (cooker, fridge, wash- our anachronistic AC power distribu- tainers labelled ‘Soder-Wick’. Always
ing machine, TV and trendy music tion with something much better and curious and easily beguiled by novel-
centre) and lighting (incandescent and truly modern: a DC power distribution ties, I asked what Soder-Wick was, and
fl uorescent) all categorically required system. By establishing the UK as a discovered it was a small reel of copper
high voltages to work effi ciently. But a leader, not a follower, DC switchover braid that had the amazing ability to
lot has changed in recent decades. We can be part of the Green Recovery and absorb and removed unplanned solder
now use LED light bulbs that could op- a signifi cant export opportunity. splashes on PCBs and other unwanted
erate far more effi ciently and effectively effects of clumsy soldering. The prod-
from a low-voltage direct current (DC) Coexistence is the way forward uct wasn’t cheap but was much less
supply. Ditto for your fl at-screen TV The Lib-Dem proposal has plenty of expensive than a proper solder pump;
and other home entertainment devic- merit, but it is not in harmony with it saved my bacon many a time.
es. A low-voltage DC supply would be the International Electrotechnical But why did they call it ‘Soder-Wick’,
far more appropriate for your comput- Commission (IEC), which supports and why the missing ‘l’? Was it a mis-
ers and other IT stuff, Wi-Fi, security maintaining a mixture of AC and DC sup- print or typo? Hardly, because the name
alarm and Internet of Things products. ply systems, to satisfy the applications was (and still is) a registered trademark.
For most people, it will also soon apply that are appropriate for one system or It was many years later that I learnt that
to the battery backup supply required the other. However, the IEC does accept ‘soder’ and ‘sodder’ are what we Brits
to keep your landline telephone and that, ‘since the late 20th century, the pro- call ‘solder’. A correspondent on Quora.
broadband router alive during mains liferation of modern power electronics com states that the word solder was bor-
failures. All of these gizmos work in- has heralded a growth in decentralised rowed from Norman French and, at the
herently on low-voltage DC sources, yet power generation. Coupled with a grow- time, was spelled without the ‘l’. The ‘l’
we are still going through the wasteful ing interest in renewable energy sources was added, probably in the 16th cen-
process of transforming 230V AC down that generate DC power and the decen- tury, by people who wanted to make
to a likely 12V DC. tralisation of the electricity grid, a new the spelling of French-derived English
Obviously, we still need higher-voltage era has begun of co-existence between words match their original Latin spell-
AC for cooking, heating, refrigeration AC and DC grids.’ Emphasising this ing. Thus, the traditional pronunciation
and clothes washing, but that’s as far as duality, Jacques Peronnet, Chair of the of the word lacks the ‘l’ sound, and this
it goes. Logic tells us that a dual-supply IEC’s Technical Committee 64, declared ‘l’-less pronunciation is preserved in
power system would make better sense earlier this year, ‘We are moving from a American English. (The word derives
and help reduce energy consumption purely AC environment to one that is a originally from the Latin verb solidare,
and hence global warming. combination of AC and DC.’ meaning to fasten together.)
So, our American friends are correct!
No novelty Do you sodder? I feel totally humbled. But I must con-
Thought along these lines is not new, No, it’s not a rude word and many PE cede that we Brits are inconsistent over
although it has had little exposure or readers indulge in soddering regularly. I pronunciation. Take the word ‘almond’;
discussion in the media. Nor, as far as I confess that I do, although at fi rst, I was some people say ‘ah-mond’, while oth-
know, has the subject had the possible unsure whether I would like it or was ers say ‘al-mond’. Do you call salt ‘sollt’
endorsement of a political party. But that even capable. It didn’t take long to dis- or ‘sawt’? ‘Goll-f’ or ‘gofe’ for the game
has now changed, with an initiative from cover that I loved it and I still fi nd the of golf? It’s a crazy, mixed-up world!
8 Practical Electronics | August | 2022