Blinking LEDs

Discussion in 'The Projects Forum' started by yurij, Jan 13, 2013.

  1. yurij

    Thread Starter New Member

    Jan 12, 2013
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    Hi - new member here. Along the lines of this, i want to make an extremely long life flashing circuit battery powered. Ideally several decades. Can be any reasonably obtainable battery (car battery, old dry cell physics batteries, etc...) and standard set of parts. But the goal is the long live. thx -yurij
     
  2. WBahn

    Moderator

    Mar 31, 2012
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    @yurij: You are hijacking someone else's thread less than four hours after it started. The OP has given no indication of wanting to run an LED flasher for decades off a battery. You will be better served starting your own thread and steering it along the specific line of discussion you are interested in. I'd be happy to participate.

    @OP: If Bill's links don't yield what you are looking for, try explaining in bit more detail what your goals are. For instance, what kind of flash rate, what kind of current flow (or battery and lifetime goal), are you looking for a circuit that just uses discrete components, or is an IC fair game, what about an MCU-based approach?
     
  3. Wendy

    Moderator

    Mar 24, 2008
    20,765
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    Welcome to AAC!

    A thread belongs to the OP (original poster). Trying to take over someone elses thread is called hijacking, which is not allowed at All About Circuits. I have therefore given you a thread of your very own.

    This was split from make a flashing LED
     
  4. absf

    Senior Member

    Dec 29, 2010
    1,492
    371
    I used a led blinking circuit based on the simulated LM3909 chip to flash an LEDs for weeks using just 3V AA battery.

    The LM3909 is available from eBay HK or China at ridiculous price of $5 a chip. The internals of the chip is simple as attached. So you can simulate it using transistors easily....

    Refer to the links here for other low current low voltage LED flashers. An alkaline "D" cell can last for 2.6 years and I think that is really fantastic.

    http://www.redcircuits.com/Page87.htm

    http://electroschematics.com/2329/led-flasher-circuits/

    http://www.ebay.com/sch/i.html?_trksid=p3984.m570.l1313&_nkw=lm3909&_sacat=12576&_from=R40

    Allen
     
    Last edited: Jan 13, 2013
  5. yurij

    Thread Starter New Member

    Jan 12, 2013
    2
    0
    I apologize for hijacking the thread. Thought the topic was close enough not to warrant a new thread. Design goals:
    1) having the device flash for decades is primary, and will drive all other decisions
    2) flash rate could be up to 1x/minute.
    3) components could be discrete or in an IC. prefer discrete, but not critical.
    4) any battery.
    I have head of a blinking devices lasting for 40 years. It was hooked up to an old physics lab battery. I have no idea what component produced the flashing.
    besides the issue of having it work for decades by design, there is the issue of what components can last that long? i.e. batteries will leak or corrode, capacitors will fail, ... considerations like this.
    thx -yurij
     
  6. WBahn

    Moderator

    Mar 31, 2012
    17,715
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    Since "decades" is plural, let's focus the discussion on the short end of things, namely 20 years.

    I think the first thing you need to look at is the availability of components that are spec'ed (or at least generally expected) to last for that long under continuous operation. I've got lots of things that have LEDs that are still working after that long, but I have lots of things that aren't, too.

    The next thing you need to look at is the availability of batteries (or potentially other power sources) that can work over that same time frame. Back when computers used battery-backed RAM to store BIOS configuration data and the like, the rule of thumb was that you would lose it in about ten years, primarily due to the self-discharge rate of the battery itself. Most batteries will self discharge in less time than that. The best ones I can find quickly seem to be lithium primary cells (NOT rechargeables) and they only talk about ten year time frames. So I think this needs to be the first thing you explore as you may be chasing a pipe dream from day one.
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    Generally it is a reasonable design goal to expect several years, but Bahn has spelled out the core limitations of your idea pretty well.

    I tried to design a set of relatively simple circuits for very long life operation a couple of years ago, and put them in the AAC book. I have linked them in my blog.

    The 555 Projects

    Look for titles with long duration in it. Some reading required.
     
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