resistor as igniter

Discussion in 'The Projects Forum' started by jasonbaker, Jul 28, 2010.

  1. jasonbaker

    Thread Starter New Member

    Jul 16, 2010
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    0
    i want to use resistors to ignite fireworks. im trying to come up with the best combo of resistor/battery to give me the fastest ignition. so far ive tried 1/4w 10 ohm resistors with 9 and 12v. the 9v ddnt light at all and 12v took about 2-3 secs. id like to get it so i could use a momentary switch to ignite without having to hold it down. anybody have any experience with this?
     
  2. windoze killa

    AAC Fanatic!

    Feb 23, 2006
    605
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    I would suggest you use ni-chrome wire instead. It is designed to get hot and won't burn out like a resistor will.
     
  3. jasonbaker

    Thread Starter New Member

    Jul 16, 2010
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    nichrome was actually my first idea. i just think the resistors would be easier if i can get them to burn out quick enough... if not ill go back to nichrome
     
  4. JDT

    Well-Known Member

    Feb 12, 2009
    658
    85
    Have you thought about getting a small lamp - like a torch bulb. Carefully crush the glass in a vice without breaking the filament. Apply voltage. Poof!
     
  5. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
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    Experiment with different types of (very) thin wires. Use what you have at home. Steel wool (not with soap) should work fine. It has to be fluffy not compressed. Or extract single wires from the wool.
     
  6. pilko

    Active Member

    Dec 8, 2008
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    1 Are your supplies capable of supplying enough current?

    2 Try lower power and/or lower resistance resistors.

    Regards

    pilko.
     
  7. CoolBeer

    Active Member

    Mar 29, 2010
    40
    6
    Lets analyze your numbers a bit.
    Code ( (Unknown Language)):
    1.  
    2. U = 9 volt
    3. R = 10 Ohm
    4. I = U/R = 9/10 = 0.9A
    5. W = U*I = 9*0.9 = 8.1W
    6.  
    Now, this is if your battery can deliver that much current, if you are using a standard 9v battery, the internal resistance will seriously put a damper on the voltage.

    Code ( (Unknown Language)):
    1.  
    2. U = 12 volt
    3. R = 10 Ohm
    4. I = U/R = 12/10 = 1.2A
    5. W = U*I = 12*1.2 = 14.4W
    6.  
    Here again, if you are using a battery that can't deliver enough omph the result will be varying. But 14.4W into a 1/4W resistor should equal lots of heat and magic smoke.

    -
    Kolbjørn
     
  8. windoze killa

    AAC Fanatic!

    Feb 23, 2006
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    Is this supposed to be a oneshot thing or something you can reuse over again? You said above "get them to burn out quick enough" which implies you will have to replace the resistors each time. Ni-chrome could be reused over and over. Other wire may burn out also but would be cheaper than resistors.

    PS. Would be nice to live in a country where you can let off fireworks legally.
     
  9. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    windoze killa,
    Fireworks aren't legal in Indiana (where the OP is from) either...
     
  10. jasonbaker

    Thread Starter New Member

    Jul 16, 2010
    10
    0
    thanks for all the input. it sounds like nichrome is the best way to go. any ideas on a slick way to rig that up? i know this doesnt really have anything to do with circuitry but i figured id ask. i know i can just tape the wire to the firework fuse but i want something easier.

    btw mcgyvr, fireworks are legal here (Indiana) now. the law changed a couple years ago.
     
  11. windoze killa

    AAC Fanatic!

    Feb 23, 2006
    605
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    I know. Thats my point. I am in Oz.... We can't use them without a licence.
     
  12. windoze killa

    AAC Fanatic!

    Feb 23, 2006
    605
    24
    Try using 2 pieces of coathanger wire with the ni-chrome stretched between the tips. Maybe insulate the coathanger wire with heatshrink. You could then place it in the required position with the fuse resting on the wire.
     
  13. aurangzeb

    New Member

    Aug 1, 2010
    9
    0
    I have used resistors to ignite sugar based propellant rocket engine. I used 3.3 ohm 1/8 watt resistor with black powder filled into a 2" piece cut from drinking straw, glued at both ends. Works like a charm.

    Check out nakka-rocketry.net for more info on ignitors.

    Aurangzeb
     
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