hours on end. Well, maybe the showers weren’t quite that long but most
people are used to taking showers in the tens of minutes. It’s easy to
lose track of time in the shower. And it does feel nice.
That’s
a luxury that’s no longer economically nor ecologically sustainable.
First of all, we’re short of water. In most areas of Australia the
powers-that-be keep telling us if we don’t be good boys and girls and
cut our water usage then we are going to run out.
(Those same
powers [read politicians] that keep blaming us wasteful consumers don’t
mention that for the most part water shortages are their fault,
because they haven’t invested the necessary dollars in water
infrastructure while population has steadily increased for much of the
last half century. But let’s not get into that argument. At least not
right now . . .)
Second, we’re short of electric power. The power
that goes to heat the water is also in very short supply. Load
shedding (ie, blackouts!) is becoming more and more common as supply
authorities attempt to cut peak loads. Those same powers-that-be keep
telling us that if we don’t reduce our consumption of power, it’s going
to get worse. (Those same powers [read politicians] that keep blaming
us wasteful consumers, etc etc etc . . .)
Putting
aside all the scare-mongering that’s going on in political circles (my
spell checker wanted to change that to circuses, which would be
perhaps more apt) it really does make sense for us, as consumers, to
try to save both water and power – if only because that means less of
our hard-earned dollars will end up in Government coffers.
One way to do both, of course, is to take shorter showers. How short?
The 4-minute shower
Believe
it or not, it is entirely possible to take a shower in four minutes –
including, if you need to, washing your hair. In fact, without
shampooing, a sub-three-minute shower is perfectly practical. People in
the bush who don’t have the luxury of hot water have been "getting"
that sort of shower for years: get in, get wet, get clean, get out!
Let’s
face it – all you really need to do is get wet, soap up and rinse off.
Get wet: 30 seconds. Soap up: 60 seconds. Rinse off: 60 seconds.
That’s two and a half minutes. Add another 60 seconds to shampoo your
hair and there’s your four minute shower – with 30 seconds left over for
good measure.
OK, if you agree that four minutes is enough time, how do you go about convincing everyone in your family?
The ST4 Shower Timer
This
rather ingenious (and patented) design is completely automatic,
turning on about 20-30 seconds after it "hears" the first "sssshhh" of
the shower – giving you enough time to adjust the water temperature –
then beeping each minute up to the magic four minutes, at which time it
sounds an alarm.
The alarm stops when you turn the shower off.
But if you try to fool it by turning the shower off for a moment and
then back on again, the alarm will start back up again. It resets after
about a minute of no-shower-sound, ready for the next person to take
their shower.
Part of the secret to this circuit is the use of
the piezo buzzer: it is not only sounds the beep/alarm, as you would
expect but it is also used as a "microphone" to pick up the splash
sound.
There’s no on-off switch; it simply operates when it hears
the shower turn on (listening for the distinctive splashing sounds of
the water). There is an internal 3-position switch and preset pot which
are adjusted to give the desired sensitivity – once set, you can
forget it.
There are also pots to control clock frequency and
tone of alarm – but these are set in the factory and should not need
touching.
It’s operated by a 9V battery (alkaline preferred)
which should last for at least 12 months. Current drain, when ready to
operate but inactive, is comparable to that of a smoke detector –
around 10-15mA.
The circuit, including the piezo, is housed on a
single PC board which fits (along with the 9V battery) into a
purpose-designed two-part case. When correctly assembled is quite
waterproof. Mounted on the shower wall it allows shower sound to enter
and beeps/alarm to escape without the circuit getting at all damp.
The
case, as we said, is in two parts. These snap together to form a nice,
tight seal around the PC board, with alignment of the two parts taken
care of by pins and holes which mate. Each half of the case is fitted
with a suction cap which allows the unit to mount to any smooth shower
wall (or even a glass screen).
While the ST4 Shower Timer is
available fully built and tested, we are more interested in it as a kit
which you assemble yourself. Even here, most of the hard work –
soldering the surface-mount components and ICs – is already done for
you. In fact, as supplied, the PC board is built and tested, ready for
you to put together
Putting it together
Assembly
is as simple as removing the backing and the centre from the
self-adhesive "donut" foam ring and sticking it, as central as possible,
onto the piezo transducer. Then similarly stick the rectangular foam
pad onto the back of the PC board (it keeps the battery snug while
preventing it shorting to or across the board), then push the PC board
into the bottom half of the case.
The
bottom half can be identified by the slots for the transducer. When
the board is pushed fully home, the foam donut "gasket" provides a seal
in a moulded housing inside the case, preventing any water entering the
case – theoretically even if dunked.
We say theoretically
because it is designed that way – but commonsense would suggest you
don’t try to prove it. Because the transducer slots are at the bottom
of the case, spray would have to be travelling upwards to enter –
possible, of course.
But the foam donut stops this water going
any further. While the transducer itself is not sealed, its internal
construction means that it is also an effective water barrier, so with
the sealing donut in place, spray cannot enter the case nor either
around or through the transducer.
All this means that the shower
timer is for all intents and purposes waterproof, especially from
spray. Once the PC board has been pushed home, the battery can be
connected and slid down into the case, alongside the (now insulated)
back of the PC board. It should be a relatively snug fit.
In the
unlikely event that the suction caps have come off the case halves in
transit, simply slide them back into their respective slots on each end
– the photos show where they go. Slide the two halves of the case
together, ensuring that the channels which hold the suction caps line
up exactly – the pins in one half won’t mate if they don’t. The two
case halves should "snap" together and that completes construction.
Testing
If
you don’t want to get wet, you can use a small unmuted FM radio,
off-station, to simulate the sound of a shower. (If your FM radio mutes
automatically, or the mute cannot be turned off, this option won’t
work. You’ll need to check it in situ – in the shower!) The FM radio
will produce predominantly white noise, which is fairly close to the
sound of a shower stream striking the bottom of the shower or bath.
Turn
the radio on and the timer should give a chirping sound after 20-30
seconds (that’s the water temperature adjustment period). Then it
should beep after each minute from there, with a series of beeps (7.5
seconds on, 7.5 seconds off) at the end of four minutes. Turn the radio
off and the timer should reset.
Mounting in the shower
The
timer always mounts vertically, with the piezo transducer towards the
bottom. The suction caps should stick very well to any ceramic tile,
glass or other smooth surface – if necessary, give ’em a lick first!
Best position for the timer is about 300-400mm from the floor but it
should work reasonably well up to about waist height.
If you need
to mount the unit higher than this, or if it doesn’t appear to be
sensitive enough, open it up and slide the switch up one notch. Don’t
mount any higher than necessary. In some very low volume showers, (eg
some gravity feeds), you might need to adjust the sensitivity right up
but this would normally be unlikely.
You should not need to
adjust any of the pots – they are preset on factory assembly. Once
mounted, give it another run, this time with the shower. It should
perform in the same way as it did in your "white noise" test.
The
only time you should need to remove the unit from the wall is to
replace the battery and this could be up to a couple of years or so!
Don’t pull on the timer to remove it, slide a knife or some other thin,
flat object under the suction caps to break the seal.
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