Practical
Electronics
Volume 52. No. 8
August 2023
ISSN 2632 573X
Contents
Projects and Circuits
Wide-Range OhmMeter – Part 1 by Phil Prosser
18
This auto-ranging ohmmeter will measure just about any resistance – from a handful of
milliohms to many megohms!
0-110dB RF Attenuator for Signal Generators by Charles Kosina
26
This RF Attenuator was designed to accompany the recent AM/FM Signal Generator
design (May 2023). It provides easy output level adjustment over a wide range.
SPY-DER 3D-printed robot by Arijit Das
32
SPY-DER is a speech and web-controlled spider robot. You can make it with a
3D-printer, a bunch of servos and some low-cost off-the-shelf electronic modules.
Universal Battery Charge Controller – 2023 update by John Clarke
We’ve made some changes to our popular Universal Battery Charge Controller
published in December 2020. It’s cheaper and uses easier-to-source parts.
38
PAS CO2 Air Quality Sensor Module by Jim Rowe
41
Continuing our series of articles on low-cost air quality sensors, this month we take a
close look at a PAS CO2 mini-board.
Series, Features and Columns
Techno Talk by Max The Magnificent
How long until we’re all out of work?
8
The Fox Report by Barry Fox
Online purchase pitfalls and parrot loops
10
Net Work by Alan Winstanley
Reports on Chinese EV makers queuing up to conquer Europe, AI becoming ever
more humanlike and news of NASA’s ambitions to return soil samples from Mars.
12
Circuit Surgery by Ian Bell
Ideal diode integrated circuits
44
Max’s Cool Beans by Max The Magnificent
Arduino Bootcamp – Part 8
50
Audio Out by Jake Rothman
Demolition Derby
56
Make it with Micromite by Phil Boyce
Part 48: Long strings and sorting arrays
62
Wireless for the Warrior
Subscribe to Practical Electronics and save money
NEW! Practical Electronics back issues DOWNLOADS – 2022 now available!
Reader services – Editorial and Advertising Departments
Editorial
Interested in robots?... Wide-range OhmMeter… Need a (cheap) book?
Exclusive Microchip reader offer
Win a Microchip SAM9X60 Curiosity Development Board
Teach-In bundle – what a bargain!
PE Teach-In 9
PE Teach-In 8
Practical Electronics PCB Service
PCBs for Practical Electronics projects
Classified ads and Advertiser index
Next month! – highlights of our next issue of Practical Electronics
2
4
6
7
7
Regulars and Services
Made in the UK.
Written in Britain, Australia,
the US and Ireland.
Read everywhere.
© Electron Publishing Limited 2023
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 2023 issue of Practical Electronics will
be published on Thursday, 3 August 2023 – see page 72.
Practical Electronics | August | 2023
9
17
25
55
68
71
72
1
| 
