flash light help

Discussion in 'The Projects Forum' started by mavrick, Dec 10, 2006.

  1. mavrick

    Thread Starter Member

    Dec 10, 2006
    16
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    im trying to build a 28 volt light for hunting. i am wanting to wire a potentiometer switch on it to control the brightness level to conserve battery time. does anyone have any suggestions on the size of switch i would need. i also need some wiring help on how to wire it up. please help.
     
  2. TrevorP

    Active Member

    Dec 8, 2006
    55
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    how many batteries are you using?
     
  3. mavrick

    Thread Starter Member

    Dec 10, 2006
    16
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    24 1.2 volt nimh batteries. so its actually 28.8 v
     
  4. TrevorP

    Active Member

    Dec 8, 2006
    55
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    ok here is what I would do: (mind you I'm really new to this stuff)

    [​IMG]

    Its probably to simple to be what you want though.
     
  5. Papabravo

    Expert

    Feb 24, 2006
    9,898
    1,722
    Since the parallel combination of two resistances is lower then either of them won't you actually be draining the battery faster then just the potentiometer alone?
     
  6. mavrick

    Thread Starter Member

    Dec 10, 2006
    16
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    well thats definitely not to simple because i dont have a clue.

    is the thing at the top where the switch goes.

    what does the squiggly lines mean.

    i dont have the switch yet do you have any suggestions. i looked at some different ones. 10k, 50k 500k, i dont know what they mean.
     
  7. mavrick

    Thread Starter Member

    Dec 10, 2006
    16
    0
    i just want a switch that will set the light as bright or dim as i want it.
    make it as simple as possible. im very new to this and dont really know what im doing. any pointers would be appreciated.
     
  8. TrevorP

    Active Member

    Dec 8, 2006
    55
    0
    yes...yes you will...

    See this is why I'm still a Noob.

    [​IMG]

    Would this not be better?
     
  9. TrevorP

    Active Member

    Dec 8, 2006
    55
    0
    Basically: (if this circuit is the best option)

    S1 is your power switch.
    R1 is a variable resistor (depends on the Watt Rating of your light bulb)
    L1 is the lightbulb
    V1 is your collection of batteries.
     
  10. mavrick

    Thread Starter Member

    Dec 10, 2006
    16
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    ok thats looking better. but the potentiometers i was looking at had like five different places on it to hook a wire. how do i wire it up.
     
  11. TrevorP

    Active Member

    Dec 8, 2006
    55
    0
    as far as i know you can get some potentiometers (that I think you are refering to) that physically stick while on the off mode (that is to say the circuit is incomplete)... and then when you turn them on you can adjust the resistance...

    If that is the case then you don't even need that power switch.

    That is all I know about potentiometers.
     
  12. mavrick

    Thread Starter Member

    Dec 10, 2006
    16
    0
    how about wiring a 6 position switch to the batteries to make different levels of brightness. has any one got any suggestions on how to do this
     
  13. mavrick

    Thread Starter Member

    Dec 10, 2006
    16
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    yes this is what i am wanting but i dont know how to wire it. the potentiometers i was looking at have 2 lugs on the bottom and 3 lugs on the side. the description was 10k potentiometer with switch.
     
  14. TrevorP

    Active Member

    Dec 8, 2006
    55
    0
    well at least one is the input... and the rest I dunno find out the make of it and Google for specs.
     
  15. wireaddict

    Senior Member

    Nov 1, 2006
    133
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    Let me offer a few pointers. First, I'd use a 100 ohm, 5-10 W rheostat. This can handle more current; most pots are 1 W or less. I don't think they ever incoroporate a built-in switch as pots do as an option. I'd use a switch in the light so the light & rheostat won't draw current when not in use. Some rheostats have 2 terminals instead of 3 where pots all have 3; if it has 3, the center terminal is the "wiper" or variable contact. Connect this terminal & one outside terminal so that the light gets brighter when you turn the rheostat shaft clockwise [with the shaft facing you]. [Connecting the third terminal is optional here.]

    One final point here: you may find battery life disappointingly short [unless they're size "C" or "D"] & the the replacement cost for 24 batteries excessively high.
     
  16. mavrick

    Thread Starter Member

    Dec 10, 2006
    16
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    thanks for the pointers dave. the light its self has rechargable batteries and they are 24 1.2 volt -28.8 volts total. i would like to get the on and off switch and brightness control together if at all possible. if i didnt use the rheostat. would the potentiometer with on and off switch hook up the same way.
     
  17. Chris Wright

    Well-Known Member

    Jul 26, 2006
    62
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    Why are you using 28 volts?
     
  18. Gadget

    Distinguished Member

    Jan 10, 2006
    613
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    I know you dont want to hear this cause it's only simple, not Simple simple, but the best option is to use a 555 timer to generate a square wave, with a potentiometer adjusting the Mark Space ratio. Use that to drive a MOSFET or even a transistor. This will vary the brightness without loosing a lot of power to heating up the High Power potentiometer you would otherwise have to use.
    I have used this setup very successfully with a 12volt spotlight for Bunnie Hunting.

    A simple simple method would be to use mutilple bulbs... say 1 watt, 5watt and 15 watt.... and switch them in single or multiple configurations. No power wasted then.
    Only draw back is all 3 bulbs couldn't be at the focal point of the reflector.
     
  19. mavrick

    Thread Starter Member

    Dec 10, 2006
    16
    0
    the light head is the style that miners use.
     
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