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By JOHN CLARKE
Can’t remember
which bins to put
out? Build this . . .
Garbage and
Recycling Reminder
Do you occasionally forget to put the garbage out? Or do you have
trouble remembering whether it’s a recycling week or a green
waste week? Build this Garbage And Recycling Reminder and
forget your “bin duties” no more.
M
OST LOCAL COUNCILS now alternately collect recyclables and
green waste on a rotating weekly basis
but how do you remember which bin
to put out with your regular garbage
bin – that’s if you remember to put
the bins out at all? There can now be
up to four bins, each with a different
colour-coded lid, to put out at different
times – the regular garbage bin plus
one for green waste and another one
or two for recyclables. So it can all be
very confusing.
There have traditionally been a couple of ways to figure out which bins go
out each week. The first is to check the
special calendar or chart that’s (usually) provided by your local council.
This chart is commonly attached to the
fridge using one of those ubiquitous
flexible magnets. However, for many
54 Silicon Chip
people, that’s a big NO; they hate the
sight of fridge magnets or anything else
plastered over the fridge.
An alternative and somewhat easier
approach is to wait until the neighbours have put their bins out and copy
them. But what if the first neighbour
to put his bins out gets it wrong and
other copycat neighbours simply follow suit? In that case, only the regular
garbage bin will be emptied and the
others left.
Now there’s a much better way of
figuring it all out – one that doesn’t
rely on memory or brain power or
other neighbours. The answer is our
brilliant new “Garbage And Recycling
Reminder” and it will allow you to
take control of your own “bin destiny”.
How? – by flashing colour-coded LEDs
on the required day to indicate which
particular bins should go out.
It doesn’t get any easier than that
but first, you have to build it.
Presentation
As shown in the photos, the reminder is housed in a small translucent
blue plastic case with a row of four
LEDs and their associated pushbutton switches protruding through the
front panel. These LEDs are red, green,
yellow and blue, one for each bin
colour. The circuit runs from a small
3V lithium button cell and the unit
can be placed on a kitchen cupboard
or bench-top so that the flashing reminder LEDs can be easily seen.
Typically, the red bin is for garbage,
the yellow for recycling, the green for
green waste and the blue for paper
and cardboard. However, this scheme
siliconchip.com.au
may differ somewhat, according to the
council. Some councils use a green-lid
bin for garbage and many councils do
not have the separate paper recycling
bin, preferring instead to combine the
paper with other recyclables so that
there’s just one recycling bin (typically yellow).
In some cases too, the green waste
bin is collected on a different day of
the week to the other bins.
The S ILICON C HIP Garbage And
Recycling Reminder can cater for all
these different situations. It’s easily
programmed using on-board links and
the pushbutton switches and each LED
can be individually programmed to
flash on a weekly or fortnightly basis
on any day of the week.
For example, if you have a garbage
collection every week and recycling/
green waste collections on alternate
weeks, the unit can be programmed
to show this. In that case, the red LED
will flash on the due day every week,
along with either the yellow LED or
the green LED. And if the paper is
collected separately, then the blue
LED can also be programmed to flash
on the due day.
Conversely, if you do not have a
separate paper recycling bin, then
this LED can be disabled to prevent
confusion.
Monthly collections?
What about monthly collections?
Unfortunately, although it’s ideal for
weekly and fortnightly collections,
the unit is not able to separate out the
actual week for a monthly collection
cycle. It can, however, indicate the day
of collection and flash the appropriate
reminder LED each week. This LED
is then simply cleared each week (by
pressing its switch) after checking the
day against the collection calendar
supplied by the council.
So at least it reminds you to check
the calendar if you have a bin that’s
collected monthly.
Starting time
The flashing reminder can be set
to start on the due day(s) at any time
that’s convenient to you. For example, you may prefer to put the bins
out the night before collection and be
reminded at say 5pm. Once activated,
the reminder LEDs will then continue
flashing for 18 hours, so that if you
miss the reminder that evening you
will be reminded again in the morning.
Alternatively, you can manually
stop the LEDs from flashing after
you’ve put the bins out. You can either
stop the LEDs all at the same time by
pressing the Clear/Program Switch
or stop each one independently by
pressing the switch immediately below it. Stopping them independently
is useful if you want to delay putting
one bin out, or even leave it until next
morning.
In any case, it’s good practice to clear
the LEDs as soon as practicable, as this
minimises the power drawn from the
3V lithium cell.
Once programmed, the unit will
then repeat its weekly/fortnightly
cycle, starting at the same time each
week. The 18-hour reminder period
should be sufficient to cover the inevitable variations in your routine and
Main Features
•
•
•
•
•
•
•
•
•
•
•
Eye-catching flashing LED reminder
Coloured LEDs match bin lid
Disable function for any LED
Weekly or fortnightly selection
Caters for up to four bins
Easy to program
Optional individual day programming
Week advance facility
15-minute advance or hold facility
Powered from a 3V lithium cell
Low current drain
any clock changes throughout the year
due to daylight saving.
Reminder adjustments
The Garbage and Recycling Reminder uses a 32.768kHz watch crystal
as the timebase for its weekly cycling.
This type of crystal is typically accurate to about 20ppm (parts per million)
which means that the unit itself should
be accurate to within about 10.5 minutes per year. Even allowing for extra
frequency drift with temperature for
the crystal, the reminder should be
sufficiently accurate for its purpose.
However, if necessary, the start time
can be shifted forwards or backwards
in 15-minute intervals. You might
want to do this to correct for drift at
the end of a year (for example), or to
simply alter the start time.
In addition, if you have mistakenly
programmed the unit so that the bins
indicated for each alternate week are
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Design software for engineers who
don’t have time to become expert
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siliconchip.com.au
January 2013 55
+3V
K
100nF
1k
22pF
12
Vdd
RA1
OSC
22pF
RB0
13
CLEAR/
PROGRAM
11
S5
1
LK4
2
LK3
2
1
LK2
2
LK1
2
RA3
RA7
K
2013
LED4
A
K
LED3
A
K
LED2
A
K
LED1
A
A
1
100 F
1k
D3 1N4148
7
K
A
2
100 F
1k
D2 1N4148
8
K
A
S2
RA4
1nF
RB3
10
100 F
1k
D1 1N4148
9
Vss
5
K
A
S1
LK1–4: 1 = ALTERNATE WEEK NOW
2 = ALTERNATE WEEK NEXT
OPEN = WEEKLY
SC
K
RA6
RB4
3
1k
S3
1nF
10k
1
RB1
RB2
15
A
D4 1N4148
RA0
1nF
10k
100 F
6
IC1
PIC16LF88-I/P
16
3V
CELL
S4
RB5
1nF
10k
1
17
18
OSC
RA2
10k
100 F
14
4
MCLR
X1
32.768kHz
D5
1N4004
1N4148
A
RECYCLING & GARBAGE REMINDER
1N4004
A
LEDS
K
K
K
A
Fig.1: the circuit is based on a PIC16LF88-I/P microcontroller (IC1). This processes the data on its RA4, RA6, RA7 &
RA0 ports as set by links LK1-LK4 and drives indicator LEDs1-4 via associated voltage doubler circuits (D1-D4 and
their companion 100μF capacitors).
transposed, then it’s a simple matter
to just swap weeks. This is easier than
having to reprogram each LED again
for the required day and time. The
reminder day for each LED indicator
can also easily be changed.
Circuit details
This is a circuit that’s just crying
out for a PIC microcontroller and
guess what . . . yep, we’ve used a PIC
microcontroller
Fig.1 shows the circuit details. Apart
from the PIC, it uses a few switches,
four LEDs, the 32.768kHz crystal, a
3V lithium cell and a few resistors,
capacitors and diodes.
To conserve battery life, a low-power
PIC16LF88-I/P microcontroller (IC1) is
used. As well as having a low current
56 Silicon Chip
drain, this micro also allows the circuit
to be operated down to 2V to maximise
the life of the 3V lithium cell.
In operation, the micro is continuously run at 32.768kHz but is normally
in sleep mode with the internal program halted for most of the time. It
wakes once per second to update its
internal timer, monitor the switches
and drive the LEDs when necessary.
It then goes back to sleep.
This sleep mode, combined with
the low clock frequency, minimises
the power drawn from the cell. In addition, the LEDs only flash momentarily when required to further conserve
battery power. In fact, the average
current drain is just 3µA without the
LEDs flashing and 151µA when all four
LEDs are flashing. This means that the
3V cell should last for about two years,
depending on the number of hours the
reminder flashes each week.
The crystal-based oscillator is form
ed using the Timer1 (T1) ports at pins
12 & 13. This is a low-power oscillator
and the timer wakes the micro up from
its sleep when its count overflows
at 1-second (1s) intervals. The 22pF
capacitors at pins 12 & 13 ensure correct loading of the crystal for reliable
oscillation.
All five switches (S1-S5) are monitored via the RB3, RB2, RB1, RB0 &
RB5 inputs, respectively. These inputs have internal pull-up resistors,
so an open switch means that the
corresponding input is pulled high
to +3V, ie, to the positive supply rail.
Conversely, when a switch is pressed
siliconchip.com.au
(closed), it pulls its corresponding
input to 0V.
Link inputs
There are four link options, designated LK1-LK4. In this case, their
corresponding inputs at RA4, RA6,
RA7 & RA0 do not have internal pullup resistors. This is because there are
actually three possible settings for
each link: position 1, position 2 or no
link installed. This allows the micro
to sense each possible setting, as described below.
In operation, the software running
in IC1 goes through a routine to determine which of the three link positions
is selected for each port. In the case of
RA4, for example, the micro does this
by initially setting RA4 as an output
and driving it high. The RA4 pin is
then set as an input and read.
If the input is read as a low, this
means that link LK1 must be in position 2 since it’s being pulled to ground
via the 10kΩ resistor.
If LK1 is not in position 2, the RA4
pin is again set as an output and this
time driven low. It’s then set as an
input again. If the reading is a high,
then LK1 must be in position 1 (ie,
RA4 is being pulled high via the 10kΩ
resistor).
Finally, if LK1 is open, then when
RA4 is driven high, the RA4 input will
also be read as a high, since the voltage
will remain stored in the 1nF capacitor. Similarly, when RA4 is driven low,
the RA4 input will also read as a low.
This process is the same for the RA6,
RA7 and RA0 ports.
Note that, for the open link position,
current leakage at the pin can cause the
input to float at a voltage somewhere
between the 3V and 0V supply rails. If
that happens, then the micro will draw
more current. To prevent this, the RA4,
RA6, RA7 & RA0 pins are normally set
as outputs, with each output set either
high or low. Each second, when IC1
wakes up, these pins are then set as
inputs and the input level is read. The
input is then set as an output again and
driven to the level that was just read
when set as an input. This process
ensures that the input is always set
high or low and is not floating.
Note that if a jumper link is changed
from position 1 to position 2 (or vice
versa), then there will be a momentary
extra 300µA current draw through
the associated 10kΩ resistor until the
updated reading corrects the driven
siliconchip.com.au
Parts List
1 double-sided PCB, code
19111121, 46 x 79mm
1 front panel label, 75 x 47mm
1 ABS translucent blue enclosure
(UB5), 83 x 54 x 31mm
1 PCB-mount 20mm cell holder
1 CR2032 3V lithium cell
1 32.768kHz watch crystal,
20ppm, 12.5pF loading (Jaycar
RQ5297, Altronics V1902) (X1)
5 SPST vertical PCB-mount micro
tactile switches with 6mm
actuator (S1-S5)
1 DIP18 IC socket
4 jumper shunts (2.54mm pitch)
4 M3 x 15mm tapped Nylon
spacers
4 M3 x 5mm pan-head screws
4 M3 x 15mm countersunk head
screws
8 M3 nuts
12 PC stakes
Semiconductors
1 PIC16LF88-I/P low-power
microcontroller (note: the ‘L’
version) programmed with
1911112A.hex
1 3mm red high-brightness LED
(20° viewing, 2000mcd or
similar) (LED1)
1 3mm green high-brightness
LED (20° viewing, 1500mcd or
similar) (LED2)
1 3mm yellow high-brightness
LED (20° viewing, 3000mcd or
similar) (LED3)
1 3mm blue high-brightness LED
(15° viewing, 1500mcd or
similar) (LED4)
4 1N4148 diodes (D1-D4)
1 1N4004 1A diode (D5)
Capacitors
5 100µF 16V PC electrolytic
1 100nF MKT polyester
4 1nF MKT polyester
2 22pF NP0 ceramic
BitScope
Digital + Analog
w
Ne del
o
M
Pocket A
nalyzer
Everything in one tiny 2.5" package !
100 MHz Digital Oscilloscope
Dual Channel Digital Storage Oscilloscope
with up to 12 bit analog sample resolution
and high speed real-time waveform display.
40 MSPS x 8 Channel Logic Analyzer
Captures eight logic/timing signals together
with sophisticated cross-triggers for precise
multi-channel mixed signal measurements.
Serial Logic and Protocol Analyzer
Capture and analyze SPI, CAN, I2C, UART &
logic timing concurrently with analog. Solve
complex system control problems with ease.
Real-Time Spectrum Analyzer
Display analog waveforms and their spectra
simultaneously in real-time. Baseband or RF
signals with variable bandwidth control.
Waveform and Logic Generators
Generate an arbitrary waveform and capture
analog & digital signals concurently or create
programmable logic and/or protocol patterns.
Multi-Channel Chart Recorder
Record to disk anything BitScope can capture.
Allows off-line replay and waveform analysis.
Export captured waveforms and logic signals.
Protocol Analyzer
Digital Oscilloscope
Spectrum Analyzer
Resistors (0.25W, 1%)
4 10kΩ
5 1kΩ
output level. This occurs within 1s, so
the extra power drain is insignificant.
LED drive
As stated, power for the circuit
comes from a 3V cell and this can be as
low as 2V when the cell is discharged.
However, some LEDs require a higher
voltage than this in order to operate at
Compatible with major operating systems including
Windows, Linux & Mac OS X, Pocket Analyzer
is your ideal test and measurement
companion.
bitscope.com/sc
January 2013 57
10k
LED1
A
LED2
A
LED3
A
4004
D5
S1
S2
S3
+
LED4
C 2012
19111121
10k
IC1 PIC16LF88
D4
100 F
100 F
+
+
100 F
S4
100 F
100nF
1k
(S4)
(FRONT OF PCB)
1k
(S5)
+
1k
(S3)
BUTTON
CELL
HOLDER
19111121
D1
Program
/Clear
RECYCLING
REMINDER
12111191
A
100 F
PC
STAKES
X1 22pF
22pF
1k
4148
+
S5
1:Alternate Now
2:Alternate Next
Open:Weekly
10k
10k
LK4
1nF
D2
LK3
1nF
4148
LK2
2
1nF
D3
LK1
2
1nF
1
4148
2
1
4148
2
1
+
1
(S2)
1k
(S1)
(REAR OF PCB)
Fig.2: follow this diagram to install the parts on the front and back of the PCB. Note that you must install the parts on
the front of the PCB first, otherwise you will not be able to fit the LEDs. The LEDs must be stood off the PCB by 4mm
and this can be done by sliding a 4mm-high cardboard template between their leads when soldering (see text).
a reasonable brightness.
Typically, a red LED that’s driven
with sufficient current to light will
have 1.8V between anode and cathode.
Blue LEDs have much more – up to
about 3.5V. A 3V supply therefore does
not provide sufficient voltage for driving the LEDs, especially as the supply
drops with cell discharge.
So, in order to make sure the LEDs
are flashed with sufficient brightness,
they are each driven via a voltage doubler arrangement comprising a 100µF
capacitor and a diode. This operates
as follows.
For LED1, RB3 of IC1 is normally set
as an input to read the level on switch
S1. However, when the LED needs to
flash, RB3 is set as a low output. The
RB4 pin is then set high and the 100µF
capacitor is now connected across the
nominal 3V supply via diode D1 and so
it charges to about 2.4V (ie, 3V minus
the 0.6V drop across the diode).
During this brief capacitor charging
period, LED1 glows due to the current
flowing through it, its series 1kΩ resistor and diode D1. Note that we say it
“glows”, because the red LED voltage
drop of 1.8V plus the 600mV diode
drop leaves only 600mV across the
1kΩ resistor, resulting in a LED current
of just 600µA.
The RB4 output is then taken low.
When that happens, the positive side
of the 100µF capacitor goes to 0V while
the negative side is pulled about 2.4V
below the 0V supply and diode D1 is
reverse biased (ie, no diode current
flow). As a result, the LED and its
series 1kΩ resistor are now connected
between +3V (ie, the positive supply)
and -2.4V, or a total voltage of 5.4V.
Subtracting the 1.8V LED forward
voltage leaves 3.6V across the 1kΩ
resistor, giving a LED current of 3.6mA
for a brief period until the 100µF capacitor discharges. The LED is therefore driven with sufficient current to
flash brightly.
Note that we do not allow the capacitor to fully discharge while RB4
is low, otherwise the capacitor will be
reverse charged via LED1 and the 1kΩ
resistor. Consequently, RB4 is taken
high some 5ms after the capacitor is
allowed to discharge and RB3 is again
set as an input.
Blue LED drive
The other LEDs are driven similarly.
However, there are some differences,
especially for the blue LED (LED4)
which has a nominal 3.5V drop when it
is lit. That means that the LED current
will be low and so it will not generally
have much brightness while ever the
100µF capacitor is charging.
The low current also means that towards the end of charging cycle, there
is minimal current through diode D4.
This low current results in a lower
Table 1: Resistor Colour Codes
o
o
o
No.
4
5
58 Silicon Chip
Value
10kΩ
1kΩ
4-Band Code (1%)
brown black orange brown
brown black red brown
voltage drop across D4 and so this allows the capacitor to charge closer to
the +3V supply.
The voltage doubler therefore drives
the blue LED at a slightly higher voltage than that applied to the red LED
and this compensates to some extent
for the greater forward voltage of the
blue LED.
Note also that when the 3V cell is
discharged to 2V, the LED current is
further reduced. However, the LEDs
all still flash with adequate brightness
due to the voltage doublers.
Supply filtering
As shown on Fig.1, the 3V supply
rail from the lithium cell is bypassed
using a 100µF and 100nF capacitors. In
addition, diode D5 is connected with
reverse polarity across the cell. This
conducts and protects IC1 if the cell
is inserted incorrectly into its holder
or if the holder is soldered to the PCB
the wrong way round.
Construction
The assembly is a snack with all
parts mounted on a double-sided PCB
coded 19111121 and measuring 45.7
Table 2: Capacitor Codes
Value
100nF
1nF
22pF
µF Value IEC Code EIA Code
0.1µF
100n
104
0.001µF 1n
102
NA
22p
22
5-Band Code (1%)
brown black black red brown
brown black black brown brown
siliconchip.com.au
Make sure that all polarised parts (LEDs, IC, diodes and electrolytic capacitors) are correctly orientated when fitting
them to the PCB. The PC stakes for links LK1-LK4 are soldered at the rear of the PCB (see text)
x 79mm. As shown in the photos, this
is housed in a UB5 plastic enclosure
measuring 83 x 54 x 31mm. A front
panel label measuring 75 x 47mm is
affixed under the case lid and is visible
through the translucent blue plastic.
Start by checking the PCB for any
faults such as shorted tracks, undrilled
holes and incorrect hole sizes. The
PCBs supplied by SILICON CHIP Partshop and from the kit suppliers are
double-sided, plated through, solder
masked and screen printed. These are
of high quality and are unlikely to have
any defects.
Having checked the PCB, sit it on the
base inside the case and mark out the
four corner hole mounting positions.
Drill these out to 3mm in diameter.
If you are using countersunk screws,
these holes should be countersunk
on the outside of the box using an
oversize drill.
An M3 x 15mm screw is then inserted into the box (ie, from the outside)
and secured in place using an M3 nut.
That done, a second M3 nut is fitted
to each corner mounting screw and
then a 15mm tapped Nylon spacer
(see photo). That should produce an
overall spacer height of 19.5mm above
the base of the case.
Fig.2 shows the parts layout on the
PCB. The top (front) side accommodates the switches, LEDs and diode D5,
while the remaining parts, including
the PIC micro, diodes D1-D3, the cell
holder and 12 PC stakes (for the LK1LK4 links) go on the other side.
Begin the assembly by installing the
parts on the front side of the PCB (note:
you will not be able to install the LEDs
if the 1kΩ resistors on the underside
are installed first). Make sure that
siliconchip.com.au
diode D5 is correctly orientated and
that it is a 1N4004. Make sure also that
switches S1-S5 all sit flush against the
PCB before soldering their leads.
Once these parts are in, you can install the LEDs. These must go in with
their bodies 4mm above the PCB and
that’s done by placing a 4mm strip of
cardboard between their leads as they
are each soldered into position. Be sure
to fit the correct colour in each location
and check that each LED is installed
with its cathode (shorter lead) towards
its adjacent switch.
If you are not sure which LED is
which (ie, they have clear lenses),
most multimeters will drive a LED on
the diode test setting. The red, yellow
and green LEDs should light on this
test (provided they are orientated correctly) but the blue LED may not light
due to its higher forward voltage drop.
Once the LEDs are in, you should
find that their tops are 9.5mm above
the PCB. This ensures that they later
protrude through the front panel.
Now that all the parts on this side are
in place, flip the PCB over and install
the parts on the other side, starting
with the resistors and diodes D1-D4
(all 1N4148). Table 1 shows the resistor
colour codes but you should also check
each one using a digital multimeter as
it is installed, as some colour can be
hard to read.
Note that the 1kΩ resistors are raised
slightly above the PCB, so that they
clear the soldered pads of the LEDs.
The remaining parts can now be
installed. A socket is used for IC1 and
this is orientated with its notched end
towards diode D4, as shown. The four
100µF electrolytic capacitors and the
cell holder must also be orientated cor-
rectly. Check that the cell holder sits
flush against the PCB before soldering
its leads. Crystal X1 can go in either
way around.
The 12 PC stakes go in the LK1-LK4
positions, with the longer end of each
stake inserted from the rear of the PCB.
These PC stakes are also soldered at
the rear of the board. That way, the
jumper shunts can be installed on the
top of the board and pushed all the way
down so that they sit flush against the
board’s surface.
Next, push the programmed microcontroller into its socket, making
sure that it is orientated correctly and
that all pins go into the socket. The
3V cell can then be fitted. Wipe both
faces of the cell with a clean piece of
cloth or tissue before pushing it into
the holder and avoid touching the cell
with your fingers (the oily film left by
finger marks on the insulation between
positive and negative terminals can
cause leakage current, thereby reducing the cell’s life).
Final assembly
Once the PCB is completed, it’s
simply installed in the case with the
LEDs and switches facing upwards and
secured using four M3 x 6mm screws.
That done, the front panel label
can be downloaded from the SILICON
CHIP website (www.siliconchip.com.
au). It’s available as a PDF file and
this should be opened and printed
out on photographic paper or plain
white paper.
Having done that, trim it to size,
then place it in position inside the lid
and use it as a drilling template for the
LEDs and switches. The LEDs require
3mm holes while the switches require
January 2013 59
SILICON CHIP
Garbage & Recycling Reminder
Clear All/
Program
+
+
+
+
+
+
+
+
+
Clear/
Prgm
Fig.3 (above): this front-panel artwork can be used as a drilling template for the case lid. It can
either be copied or downloaded from the SILICON CHIP website and printed out. The photograph at
right shows the M3 x 15mm standoffs and the two extra M3 nuts at each corner mounting position.
3.5mm holes. Drill small pilot holes
first (eg, using a 1mm drill) before
enlarging them to the correct size.
Alternatively, you can use wad
punches to make the holes if you have
a set of these.
Finally, the label can be affixed to
the inside of the lid using a few spots
of neutral-cure silicone.
Programming the schedule
The Garbage and Recycling Reminder is set (or programmed) for the
collection days and weeks using links
LK1-LK4 and the five switches.
Note that this programming should
not be confused with the software file
(1911112A.hex) that’s programmed
into the PIC (IC1). You can either program the PIC yourself (the software is
available on the SILICON CHIP website)
or you can purchase a programmed
PIC from the SILICON CHIP Partshop.
Similarly, a programmed PIC will be
supplied if you buy a complete kit of
parts (if available).
Now let’s see how the reminder
schedule is programmed. The first step
is to install the appropriate jumper
link for each reminder LED. LK1 is
for LED1, LK2 is for LED2, LK3 is for
LED3 and LK4 is for LED4. A jumper
in position 1 selects a fortnightly reminder period, with the LED flashing
on alternate weeks starting with the
current week.
Position 2 also selects a fortnightly
reminder cycle but starting on the next
week. And finally, leaving the jumper
link out selects a weekly reminder
cycle (in that case, the jumper can be
stored by placing it over only one of
the pins).
For example, if you want LED1 to
flash weekly, leave out the jumper
for LK1. If you want LED2 to flash
fortnightly starting with the current
week, install a jumper on LK2 in position 1. And if you want LED3 to flash
fortnightly starting with the next week,
install a jumper on LK3 in position 2.
Note: for monthly collections, select
The front panel
label sits inside
the lid of the
translucent blue
case. The unit is
easy to program
and has very low
current drain,
with a battery
life of up to three
years.
60 Silicon Chip
the weekly option and then refer to
the collection calendar for the correct
week day.
If you don’t have four separate
bins, then you will want to disable
one (or more) of the LEDs to prevent
confusion. In that case, the jumper
position for that LED is not important
since we disable it with the schedule
programming.
The next step in the schedule programming is to wait until the exact day
and time you want the reminder LEDs
to start flashing. If you have collections on different days, then this can
be sorted out later on. Just choose the
main collection day.
The next programming steps involve
using the pushbutton switches. There
are two basic types of switch actions. A
long press for six seconds or more is for
programming the weekly/fortnightly
reminder sequence. A shorter press
for at least one second is for clearing
or disabling the reminder LEDs.
It’s just a matter of following this
simple step-by-step procedure:
Step 1: at the correct time, press and
hold the program button (labelled
“Clear All/Program”). After about six
seconds, the LEDs selected for the
“Weekly” and “Alternate Week Now”
fortnightly reminders will flash once,
one after the other. Then the LEDs selected for the “Weekly” and the “Alternate Next” fortnightly reminders will
flash in sequence and this particular
sequence will then be repeated.
The entire cycle will then be repeated while ever the Clear All/Program
button is held down. This confirms
which LEDs flash on successive weeks.
Step 2: to prevent one LED from flashing, continue pressing the Clear All/
Program button and then press and
siliconchip.com.au
hold the switch associated with the
LED to be disabled. The LED will initially glow at a brightness that depends
on the cell voltage. Wait until the LED
briefly flashes at a greater brightness,
then release its switch. The LED will
now be disabled and will be prevented
from flashing (unless the unit is programmed again with the Clear All/
Program button as described above).
Step 3: release the Program button. That
will start the Recycling And Garbage
Reminder which will now flash the
appropriate LEDs to indicate the bins
for the current week.
Once the bins are out, the LEDs can
all be cleared by pressing the Clear
All/Program switch for a 1s period
(ie, press and wait until all the LEDs
have flashed). Note: do not press this
switch for more than about 5s or you
may end up reprogramming the unit
to start at this time and day.
Alternatively, individual LEDs can
be cleared by pressing the switch associated with that LED until it flashes.
If any LED is not cleared, it will be
automatically cleared after 18 hours.
If your bins are all collected on the
same day, then that completes the
programming procedure. However,
if you have a bin that’s collected on
a different day or want to make other
changes, you need to carry out a few
additional steps.
As mentioned previously, you can
swap the week, change the reminder
day for a particular LED and shift the
reminder starting time forwards or
backwards in 15-minute steps. These
alterations must be done outside of the
18-hour reminder period. If you are
not sure if you are out of the reminder
period (because the LEDs were each
cleared individually), simply press
the Clear All/Program button for 1s
to clear the 18-hour reminder timer.
Here’s how the make the changes:
Changing days: to change the day for
any LED, press and hold the switch
for that LED for six seconds. The LED
Here’s another
view of the
completed PCB
from the front.
Links LK1-LK4
along the top
edge set the flash
cycle for each
LED (see text).
will then flash. Release the switch after
a single flash for a single day advance
or keep holding the switch for more
days. The LED will flash at a 1s rate
and the schedule will advance by as
many days as the LED flashes.
The advance can be up to 13-days
ahead, with the 14th day returning to
the original setting.
Changing weeks: if you want to swap
the weeks on which the alternateweek LEDs flash, this can be done by
simultaneously pressing the two inner
switches, S2 & S3. LEDs 2 & 3 will
then each flash once to acknowledge
the change in week. Essentially, this
moves the cycle forwards by one week.
The week is only swapped once
for each switch pressing. To change
the week again, the switches need to
be released for a second or more and
then pressed again.
Forward time adjustment: the starting
time can be adjusted forwards (ie,
so that the flashing reminder starts
earlier) by simultaneously pressing
switches S3 & S4. This will case LED4
to flash at a 1s rate and the timer will
move forwards by 15 minutes with
each flash.
Backward time adjustment: pressing S1
& S2 at the same time moves the reminder time backwards. In this case,
LED1 flashes at a 1s rate and the timer
moves backwards by 15 minutes with
each flash.
Note that while the forward time advance can be incremented by as many
15-minute intervals as required, this
is not true for the backwards setting.
In this case, to delay the reminder,
the timing is paused by 15 minutes
for each backward timing adjustment.
This pause “delay” is limited to a
maximum of 4 hours and 15 minutes.
In addition, any timer pausing is
cleared each time a forward time adjustment is made.
Alternative reminders
Finally, if you are part of the “i-gen
eration” (or aspire to be), you may
prefer to use a smartphone app instead
of building this unit. For example, a
Garbage Can Reminder App is available from the Apple App Store and is
suitable for iPhone, iPad and iTouch
products. You enter the collections
days into the calendar application
and you are then reminded of the day
– see https://itunes.apple.com/au/app/
garbage-can-reminder/id542396945?
Alternatively, your local council
may offer a free smartphone application for their garbage and recycling
collections. For example, Randwick
council in NSW has an app available
at http://www.randwick.nsw.gov.au/
Your_Council/Whats_happening/myRANDWICK_app/index.aspx
Log onto your local council’s website to see if they offer anything similar.
Of course, an app only works if your
smartphone is switched on or you
haven’t left it in the car or upstairs.
We think that placing the Recycling
and Garbage Reminder on a shelf in
SC
the kitchen is more effective.
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January 2013 61
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