Flash grenade.

Discussion in 'The Projects Forum' started by Ace1911, Jul 18, 2014.

  1. Ace1911

    Thread Starter New Member

    Jul 18, 2014
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    For quite some time I've been trying to figure out the proper circuit to use. I have been designing a flash grenade for airsoft, its just leds and a siren in a small shell. I have been trying to make a circuit that has a delay power on and only stays on for about 5 seconds. Im using a 9volt battery to power everything. I just need someone to help me with the circuit. Im fairly new to this so please any help is appreciated.
     
  2. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    Let me get this right.

    User pushes a button. This starts a delay of X seconds (or minutes). Once delay X end, the devices turns on for 5 seconds, then tuns off. Right?
     
  3. Ace1911

    Thread Starter New Member

    Jul 18, 2014
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    Yes exactly.
     
  4. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    Hm. For me, the 5 second ON time is easy. The hard part, for me, is how to have a delay between the user pushing the button and the 5 second ON time.

    I know a few people around here who are going to call me names... But the only way I see how to do the whole thing is to use a microcontroller. It is probably lack of experience on my part, but I just don't see how to have a timed delay and then have timed ON time. With a microcontroller, I can have the button, I can have the delay and I can have the 5 second ON time after the delay. The microcontrollers are small, most of them work from 9 volts, programming resources are usually free, that is how I would do it.
     
  5. Ace1911

    Thread Starter New Member

    Jul 18, 2014
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    Thank you very much. Ill look into that.
     
  6. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    A microcontroller would be the most compact solution, but if you wanted instead to use discrete components you could do it like this with a single IC :
     
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  7. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    My own experience is with Arduino boards (they use ATmel microcontrollers). So for a small device like this (fist size or little larger) I would probably use Arduino Nano or Arduino Micro.
     
  8. KabulDubai

    New Member

    Jul 19, 2014
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    A circuit which you're trying to make requires that a user presses a button and from that time and onwards a circuit remains on for 5 seconds will perhaps make you use a alarm device like we've in a mobile phone alarm but your circuit will have to have a clock as well so that when a user presses a button the time gets recorded by a clock timing chart and from then and when a user will press on it'll tick on '1'(including recorded time)which will activate the AND Gate for every 1 second interval & after 5 seconds this clock will tick on '0' which shall be an off exactly when the clock ticks on 'STOP' .So,for this you'll have to use a microcontroller whose price must be in a list of Jameco electronics in San Francisco,CA,therefore see www.jameco.com who can also give you a chart of wiring scheme for this circuit through their own website.
     
  9. KabulDubai

    New Member

    Jul 19, 2014
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    I've drawn your timing diagram and circuit diagram of DelayedPulser and I also cleaned a laptop's charger wire like new for our help in the black background for the timing diagram's black background and it shall also be used by other companies also who manufacture solar panels like Jameco electronics whom I've known from Ajman,UAE in 1988-89.
    You can also use XOR gate for sequential flow of 1's upto 5 seconds with A to Q for the clock itself to return to A in which after those passed,5 seconds utilised each time by a user shall be with the clock setting with toggle after each 8 hours period(8hrsx3=24).
     
  10. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Did a timing circuit for my son for an Airsoft granade with a PICAXE 08. It had a 4pin header that would allow small plugs to select different delay times. Could also have used DIP switches. Pushbutton start. as well as stop.

    Ken
     
  11. CIVEDM

    New Member

    Jan 28, 2014
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    That's an awesome idea. Just a suggestion,... make sure you have plenty enough super bright LEDS facing all direction and most importantly,... instead of just turning the LEDS on for 5 seconds or so,... have them all simultaneously strobe for 5 seconds. That screws up someones vision way more than just a steady flash or better yet have two modes. steady on and strobe. Just like real tactical lights.

    Here a good youtube video showing you the difference.
    https://www.youtube.com/watch?v=okPir0dFXOo
     
    Last edited: Jul 19, 2014
  12. wayneh

    Expert

    Sep 9, 2010
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    Good idea. There's a phenomenon of human perception that causes strobing at ~10Hz to be seen as brighter than a constant light, power held equal.
     
  13. CIVEDM

    New Member

    Jan 28, 2014
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    Yea I remember someone saying that when I was asking about a desk project of mine.
     
  14. CIVEDM

    New Member

    Jan 28, 2014
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    Oh and another thing,... he should have a few LEDs lit ever so dim so that if he throws it on the dark the person it's meant for will be able to see it and they will be compelled to look at it as well. Maybe have the dimmed leds dance a bit instead of being steady on. You want the person to look at it so anything to catch their eye.
     
  15. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    .... can cause epileptic seizures in some people. It's dangerous.
     
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