SILICON
SILIC
CHIP
www.siliconchip.com.au
Publisher
Leo Simpson, B.Bus., FAICD
Editor
Nicholas Vinen
Got a project idea? There’ll be a
badly designed app for that!
Derby Street, Silverwater, NSW 2148.
In thinking up ideas for projects to publish in Silicon
Chip, we have a lot of hurdles to overcome and they
seem to be multiplying.
Increasingly, we face the challenge of coming up with
designs that aren’t already available commercially (eg,
from China) for less than the retail cost of the parts. We
also have to consider the availability of smart phone
apps which purport to do a similar job.
But while there is often an “app for that”, it usually turns out to be a bit of
a joke. For example, while working on the Earthquake Early Warning project
published this month, we decided to try out a few earthquake alert apps first.
One claimed to provide “earthquake early warning” but seems to rely mostly on alerts from the USGS Earthquake Notification Service which states: “Information for earthquakes in the U.S. is generally available within 5 minutes;
information for earthquakes elsewhere in the World is generally available
within 30 minutes”.
Hmm. Getting a message 30 minutes after a quake does seem a little pointless!
Now, the app does claim that it uses your phone and others running the
same app in the general area to directly detect and warn of earthquakes but
since there haven’t been any earthquakes in our area in the last couple of
months, we have no way of evaluating its true effectiveness. What if nobody
nearby is running the app? How do we know their earthquake detection software really works?
And this is not an isolated case. For example, we’ve long thought that pretty much all “sound meter” apps are generally useless since the microphone
in your phone doesn’t have enough dynamic range and isn’t calibrated. And
audio oscillator apps cannot be guaranteed to generate the frequencies you
might select. You might hear a tone but it might be far removed from the frequency it purports to be.
This was driven home for me while watching an episode of the TV show
“Top Gear” a few years ago where the host as the time, Jeremy Clarkson, attempted to measure the noise levels of three different cars using his iPhone.
He got pretty much the same reading in each case (within 1dB); possibly because the microphone was being overloaded by the noise. And the app “sort
of” works, while the microphone sensitivity is an unknown and therefore any
measurements may have very doubtful accuracy.
Maybe this was a stunt; surely a TV show with a multi-million dollar budget could afford a proper sound level meter? But I wonder how many users of
this sort of app realise its limitations?
Light meter apps also must be suspect. While seemingly useful, we have to
wonder just how accurate they are; presumably they sample the light using
the phone’s camera and its accuracy will vary from model to model. And the
apps rarely provide any information as to the reliability or precision of their
readings. They could be spot on or way off. Unless you compare them directly
to a calibrated instrument, how would you know?
Having said all that, some apps definitely are handy. For example, we’ve
published circuits in the past to generate white noise, water sounds and so on
but now there are free “white noise” apps which make such projects obsolete.
And that’s just one example that comes to mind.
So when you see a project in the magazine, know that we’ve considered all
the above. And before you rely on any app, make sure you check to ensure
that it can deliver what it promises.
ISSN 1030-2662
Recommended & maximum price only.
Nicholas Vinen
Technical Editor
John Clarke, B.E.(Elec.)
Technical Staff
Ross Tester
Jim Rowe, B.A., B.Sc
Bao Smith, B.Sc
Art Director & Production Manager
Ross Tester
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Glyn Smith
Phone (02) 9939 3295
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glyn<at>siliconchip.com.au
Regular Contributors
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David Maddison B.App.Sc. (Hons 1),
PhD, Grad.Dip.Entr.Innov.
Geoff Graham
Associate Professor Graham Parslow
Ian Batty
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Brendan Akhurst
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