My project idea (early concept)

Discussion in 'The Projects Forum' started by tom7891, Oct 2, 2011.

  1. tom7891

    Thread Starter New Member

    May 16, 2011
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    Okay, so i've just started my BTEC electrical course and i've been asked to make an original electronic product. The idea i've come up with is an item tracker for when items are lost in the house. I'll go through my idea before askng the question.

    The main part will be a remote control of sorts. This control will have maybe 5 buttons each corresponding to a tag on an item. The tag will be a simple infra red reciever. The control will use infra red and will beep if pointed at the tag's general direction, but only if the button corresponding to the tag is pushed. The general idea is that you point the remote around the house until it beeps, giving an idea of where the item is (which has one of these tags stuck to it.)

    So, coming back to my question. Well two questions actually. Is this idea actually doable and how can i make these tags as small as possible?

    Sorry about being vague, but i've literally just came up with this idea :p
     
  2. wayneh

    Expert

    Sep 9, 2010
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    4,277
    IMHO, IR is not a super choice for this since the device needs to "see" the remote. Most of my lost items are lost because they're NOT in plain sight, cellphone under the newspaper, TV remote slipped under the sofa cushion, etc. Something that could cause a chirp when queried would be useful. Trouble is power. You need something that uses almost no power until it's asked to respond to your remote.
     
  3. tom7891

    Thread Starter New Member

    May 16, 2011
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    hmm, didn't think of that. Could be quite tricky...
     
  4. Georacer

    Moderator

    Nov 25, 2009
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    Do you live alone?

    Most uCs have interrupted inputs (I know PIC does). They are powered off until the input is energized or de-energized.

    A friend of mine used a solar panel to wake his automated sprinkler at night.

    A piezo-speaker could energize the PIC each time you make a noise. Even better, with a filter it could respond to certain frequencies. In a noisy environment however that wouldn't work.
    Other options could be light (or lack of).

    The size will be an issue though.
     
    Last edited: Oct 2, 2011
  5. Adjuster

    Well-Known Member

    Dec 26, 2010
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    I would think this probably needs to be a radio application. A protocol where the receiver "sleeps" most of the time, but "wakes" say for a few milliseconds every few seconds might keep the power consumption down.

    Your transmitter would need to squawk the tag address repeatedly, at a rate such that a full address would soon fall into one of the tag's waking moments.

    Depending on your course requirements, would it be acceptable to make a scaled-down version using an IR link instead of RF, accepting that it would be less functional?
     
  6. tom7891

    Thread Starter New Member

    May 16, 2011
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    Yeah, radio waves was my other thought. I don't think there are any boundaries electronics wise.
    Another thought i came up with was RFID, not sure if it would be practical though. The remote could have a cheap reader built in, and the tags could be rfid tags?
     
  7. someonesdad

    Senior Member

    Jul 7, 2009
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    Also do a web search; there have been a number of products over the last couple of decades that do this; IIRC, they used RF for the task.

    Me, I just use the UFD.

    (Uterine finding device for those of you not shackled to a SWMBO).
     
  8. Adjuster

    Well-Known Member

    Dec 26, 2010
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    A system using passive tags, or tags powered solely by incident RF would get around the problem of battery life. The sweeper would then have to be a bit muscular though, and you might have compatibility/interference/licensing issues.

    Visions of unfortunate effects on some poor soul with a cochlear implant or a heart pacemaker, as we scan for our lost car keys. Perhaps it's worth looking into what frequencies and power levels are acceptable.
     
  9. Adjuster

    Well-Known Member

    Dec 26, 2010
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    Oh, and by the way, congratulations for coming and asking an intelligible question about a project, with sufficient detail that we can begin to think about it. Many people come with questions so poorly expressed that they are an annoyance.

    I probably won't be able to help you much more with this, but good luck with it!
     
  10. tom7891

    Thread Starter New Member

    May 16, 2011
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    Yeah, the pace maker issue is a bit of a problem.
    May ask if infra red will be ok. Can you have different strengths of infra red signals?
     
  11. #12

    Expert

    Nov 30, 2010
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    It was called a cat tracker when I bought one, several years ago. I gave it to my sister to attach to her glasses. Click, beep, "There's my glasses!" Much like the "find" button on my battery operated telephones. Click, beep, "There's my phone!"
     
  12. tom7891

    Thread Starter New Member

    May 16, 2011
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    thanks for the help.
    I'm going to look into rf, see what the lecturer thinks. If there is a problem, i'll stick to infra red.
     
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