annual timer in a field

Discussion in 'The Projects Forum' started by Andrew Wolfenden, Oct 14, 2013.

  1. Andrew Wolfenden

    Thread Starter New Member

    Oct 11, 2013
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    Hi,
    I wish to embark on a project of which I have no idea where to start (or end), I have a Mechanical back ground not electronics.

    I wish to make a series of boxes which can sit outside with no external power supply.

    Box 1 needs an LED to light up for 1 minute once a week
    Box 2 needs an LED to light up for 1 minute once a month
    Box 3 needs an LED to light up for 1 minute once every 4 months
    Box 4 needs an LED to light up for 1 minute once a year.

    These boxes need to be as maintenance free as possible, keep good time (so they do not need re-visiting, Also cheap to make.

    The container itself is easy to make, but the timer inside is where I fail. Can you help?
     
  2. Andrew Wolfenden

    Thread Starter New Member

    Oct 11, 2013
    4
    0
    Bits I forgot to add
    The LED will need to light up on set day.
    Box 1 Sunday at 9:00PM
    Box 2 first Saturday of the month at 9:00pm
    Box 3 first Wednesday of the 4 month
    Box 4 third Sunday of June.
    This becomes a pain as leap year and day light saving etc come into play.
     
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    how do you intend to power it?
    how long do you expect it to last on this power supply?
    how big are these "leds" (specs?)
     
  4. Andrew Wolfenden

    Thread Starter New Member

    Oct 11, 2013
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    The power will have to come from an internal battery, and it would be good if the boxes could last two years at a time without any maintenance. I only require 1 clear LED to be illuminated per box, which in turn will illuminate several fibre optic cables.
    The boxes are to be used as game pieces, for people who may travel some distance.
     
  5. mike__b

    New Member

    May 30, 2012
    5
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    Can you give a bit more information?

    What sort of scale is this on? Box dimensions. You say the boxes will light up fiber optics, are those inside or outside the box?

    Regular store bought batteries might last that long, but getting something to accurately time those might be a challenge. A small program written for an MSP430 or similar would probably work. They're using those in residential door locks and such with AA batteries, but those are driving motors, your load would seem to be much less.

    You can pickup an MSP430 dev kit for about $10.
     
  6. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    You will need a "realtime" clock/calendar IC and a microcontroller IC.

    Ken
     
  7. Andrew Wolfenden

    Thread Starter New Member

    Oct 11, 2013
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    The size of the box is no set, but as small as possible. the LED will be in the box and the fibre optic will come oit of drilled holes in the box. some one mentioned a GPS chip, and someone else has said that the clocks that work of a radio time signal must have a chip in it, or use of a RTC? any thoughts?
     
    Last edited: Oct 16, 2013
  8. John P

    AAC Fanatic!

    Oct 14, 2008
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    You can get timing as accurate as a digital watch fairly easily, though you'd be challenging the hardware with an outdoor environment. If the budget will allow it, you could consider a system that wakes up (let's say) 24 hours in advance of the desired event, and resets its clock to some highly accurate broadcast timebase like GPS or Zulu Time; then it would be all set to give its display at just the right moment. But I'd be dubious about something that has to live outdoors for a couple of years where you can't test its integrity until the exact moment when you need it.

    Edited to say that I just looked up the current consumption of my favorite microprocessor, the PIC16F690. With a 32.768 kHz watch crystal to run it, it draws less than 20 uA, which means less than 200 mA-hrs in a year, and a AA battery has over 1000 mA-hr capacity, so it looks as if a pair of AA cells would run the thing very nicely.
     
    Last edited: Oct 16, 2013
  9. wayneh

    Expert

    Sep 9, 2010
    12,090
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    For what it's worth, my cheapo "atomic clock" runs on a pair of AAs for at least a year. These things check on the broadcast time every now and then and maintain an accurate time. They even adjust for DST, show moon phase and temperature.
     
  10. MaxHeadRoom

    Expert

    Jul 18, 2013
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    There are quite a few timer/clock modules based around the PCF8583 (try Google) with battery back up, for interfacing with a small Pic.
    Also you could look at a rechargeable battery and use one of the simple solar cell modules sold for yard light etc mounted on the outside of the box.
    Max.
     
  11. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    arduino + RTC module + battery pack + LED/resistor + suitable enclosure
    If you want "simple" setup by any user then you will need an LCD also and some buttons to set the time/date or it can be set via USB/serial during firmware flashing..
    Then its just a matter of writing the code..
     
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