Silicon Chip – June 2019

112 Silicon chip Australia’s electronics magazine siliconchip.com.au

Coming up in Silicon chip

12V Battery Isolator

This solid-state device automatically connects an auxiliary battery for charging

when the vehicle alternator is running. It can handle charge currents in excess

of 100A, does not get hot during operation, produces little to no EMI and has

a low current drain when off.

Audio Millivoltmeter

This Arduino-based meter has three input ranges (200mV, 2V and 20V) plus

balanced and unbalanced inputs. It provides an accurate audio signal level

reading in μV/mV/V and dBV. It has better resolution than our previous de-

signs, in a more compact package.

Micromite LCD BackPack V3

This new Micromite BackPack is still cheap and easy to build, but now sup-

ports larger touchscreens, plus has onboard provision for a real-time clock,

temperature, pressure and humidity sensors, an infrared receiver and even

more useful functions!

Rechargeable LED bicycle light

This device uses a switchmode converter to drive a string of LEDs from a re-

chargeable lithium-ion battery pack. It has multiple light modes and automati-

cally reduces the LED current to prevent overheating.

Radiation and Electronics

The operation of electronics in aircraft and spacecraft (and here on Earth too)

can be affected by radiation. It can even cause permanent damage. This ar-

ticle explores the sources of radiation that can affect electronics, what prob-

lems that radiation can cause and how to prevent or overcome those effects.

Speech Synthesis with Raspberry Pi and Arduino

Use a very low-cost Raspberry Pi Zero and this small add-on board to allow

any computer or microcontroller to produce synthesised speech in a variety

of languages and accents, and play back music and audio recordings. If you

use a Pi with WiFi, it can even play internet radio streams.

Note: these features are planned or are in preparation and should appear

within the next few issues of Silicon chip.

The July 2019 issue is due on sale in newsagents by Thursday, June 27th.

Expect postal delivery of subscription copies in Australia between June 25th

and July 12th.

Notes & Errata

DSP Active Crossover/Parametric Equaliser, May 2019: in the ADC circuit diagram on pages 30 & 31 (Fig.4), two pairs of

22μF capacitors are shown between the ±9V rails and ground but only one pair actually exists. Also, one 10μF bypass capaci-

tor is shown on the +5V rail but there are actually two, with the other located close to IC4/IC5. Finally, the two 47μF coupling

capacitors after FB1/FB2 are actually polarised, with the positive ends to FB1 & FB2.

Advertising Index

Altronics...............................36-39

Ampec Technologies .................. 9

Cypher Research Labs............... 6

Dave Thompson ..................... 111

Digi-Key Electronics ................... 3

Emona ....................................IBC

Hare & Forbes ......................OBC

Jaycar ...........................IFC,53-60

Keith Rippon Kit Assembly ..... 111

LD Electronics ........................ 111

LEACH Co Ltd .......................... 25

LEDsales ................................ 111

Microchip Technology ............... 11

Mouser Electronics ..................... 5

Ocean Controls ........................ 12

PCB Designs .......................... 111

Rohde & Schwarz ....................... 7

Sc Frequency Counter ............. 31

Sc Vintage Radio DVD ........... 108

Silicon chip Wallchart ............. 76

Silicon chip Shop......44,104-105

Silicon chip Subscriptions ...... 99

The Loudspeaker Kit.com ........ 65

Tronixlabs ............................... 111

Vintage Radio Repairs ........... 111

Wagner Electronics .................. 10

Wiltronics Research ................... 8

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