Arduino bin reminder
This simple project came about
when one person in our street put
out the wrong coloured bin. This created confusion in the street as most
people copied what bin the earlier
neighbour had put out, including
yours truly.
I decided to check the council
website for the bin timetable. After
wasting about half an hour, I found
that the council, in its wisdom, had
put the 2024 calendar up and deleted
the 2023 timetable before the end of
the year!
I remembered Silicon Chip published a bin reminder project some
years ago (January 2013; siliconchip.
au/Article/1315).
While it is an excellent design
with many great features, I wanted
something very simple with no
buttons for anyone to fiddle with.
The circuit presented here is
straightforward, using little more
than a real-time clock module and
an Arduino Uno. All of the programming is done in the sketch
code rather than using buttons. I
have commented the sketch so it is
easy to set your bin colour LEDs and
their timing.
If, when the Arduino is powered
up, it detects that the real-time clock
module does not have a valid date
and time, it sets them to the date
and time that the sketch was compiled and uploaded, which should
be just a few seconds earlier. That
slight time difference will be inconsequential to the device’s job.
The sketch changes the display over at 1:30am every Sunday
morning, to tell the user what the
bin colours are for the week. When
the circuit boots up, the LEDs for
the current week will be displayed.
The reminder will then change to
your setting for the alternate week
the following Sunday morning. The
Sunday after that, the LEDs will
swap back again. This cycle continues while power is applied.
The unit must be kept powered
up continuously (do not press the
Arduino reset once programmed).
As shown in the circuit diagram, I
achieved that with a trickle-charged
9V NiMH battery.
The software sketch for this project can be downloaded from:
siliconchip.au/Shop/6/352
Geoff Coppa,
Toormina, NSW. ($80)
flows through LED2 (red).
The 5V supply rail is chosen carefully because it needs to be sufficient
to light the LEDs but not so high that it
could cause reverse breakdown in the
transistor or LEDs, which could cause
both an erroneous result and possibly
damage the transistor.
The fourth section of the chip (IC1d)
is not used, so its inputs are tied to
the 0V rail.
Raj K. Gorkhali,
Hetauda, Nepal ($50).
siliconchip.com.au
Australia's electronics magazine
June 2024 97
