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Different power supply or just throw in a voltage regulator?

Discussion in 'Power Electronics' started by LucidSymmetry606, Mar 15, 2015.

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  1. LucidSymmetry606

    LucidSymmetry606

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    Mar 15, 2015
    Hello to all. I hope I've posted this in the proper section and I apologize in advance if I haven't - this seemed to be the right place.

    I'm relatively new to the world of circuitry/electronics and I hope my question won't give anyone an aneurysm due to its simplicity. I'm re-purposing a wireless doorbell and due to size constraints I'd like to change the receiver's power supply from three AA batteries down to a single 12-Volt "23A" battery. I've replaced the speaker in the receiver with a 3-Volt relay. Must I use a voltage regulator or will I get away with using a proper-value resistor to limit the voltage? Time is pressing for this project and I'd like to go with the option of least resistance and highest simplicity. Furthermore, would it be easier (and feasible) to instead use one or two 3-Volt button cells? Whichever power source I go with, it needs to power up to three indicating LED's at any given time so I can't simply get a 1-Volt relay and use a single AAA or AA battery.

    More information: the unit is to be used for really short periods of time. I'm using this wireless doorbell receiver as the power source for igniting my model rockets. As stated previously, there's a relay with a 9-Volt that will be fed to a single e-match. As you can imagine, the unit will be set down, turned on, and activated after which it will be quickly turned off - this thing isn't expected to be on for long periods of time. I also do not mind having to change the batteries often.

    There is however another option I have considered: I could use the 12-Volt "23A" to set off the e-match and go with the original two/three AAA battery configuration for the receiver. Do you think that the battery specified will have enough juice to make a 15Ω, 0.125-Watt resistor light up quickly?

    I've made some neat modifications to both the transmitter and receiver. Once I've successfully finished this project, I'll post pictures if anyone's interested.

    Thank you very much for any help. Take care.
     

    Attached Files:

  2. chopnhack

    chopnhack

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    Apr 28, 2014
    Have you any concerns with stray wavelengths that could be received, possibly igniting your fuse prematurely?
     
    LucidSymmetry606 likes this.
  3. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    The lighter battery will not work. The best is an alkaline 9v battery. It will blow up your resistor.
    Use 3 x AAA cells as this is the correct voltage for the front end.
     
    LucidSymmetry606 likes this.
  4. LucidSymmetry606

    LucidSymmetry606

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    Mar 15, 2015
    I have had that thought come to mind plenty of times. However, my family and I have owned several wireless battery-operated doorbells for a very, very, very long time and we haven't had a single false or phantom ring. Only a confirmed ding-dong ditch or two... What's the probability of the receiver catching stray waves?
     
  5. LucidSymmetry606

    LucidSymmetry606

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    Mar 15, 2015
    I tested the lighter battery right after my post. I wish I waited and read your response first because... It didn't work. Lol. I held the battery to the e-match for a good 5-7 seconds and it only managed to suck a good chunk of life from the battery. Yeah. Only the 9-Volt alkalines will do the trick. That or a car battery...
     
  6. chopnhack

    chopnhack

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    Apr 28, 2014
    I am not sure what the probability is, just mentioned it since the risk of injury could be great - regardless of what the chances are.
    Don't get me wrong, I like cool projects that repurpose items instead of trashing them, but why not use wire and battery for igniting?
     
    hevans1944 likes this.
  7. LucidSymmetry606

    LucidSymmetry606

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    Mar 15, 2015
    It's cumbersome and messy. I have a loop of 30 meters of wire. I've gotten myself and the insides of my car dirty with mud and stuff the wire picked up from the ground. It also takes a while to wind up the cable. There's also the issue of the cable coiling like a spring and pulling out the igniter if I don't leave a gratuitous amount of slack.
    I just remember seeing my old science teacher having a similar set-up once and I guess I was intrigued by the idea. It's simpler to wipe off a single module and a few feet of wiring rather than 30 meters of it.

    The switches I've implemented in the design don't have me turning on the unit the thing I'm going to be setting off is a few feet away from me. I don't plan on hooking up the igniter to the receiver when the receiver is on standby and ready to receive stray signals. It seems I've eliminated as much risk as possible. Any ideas?
     
    chopnhack likes this.
  8. LucidSymmetry606

    LucidSymmetry606

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    Mar 15, 2015
    *...have me turning on the unit until the thing I'm going to be setting off...
    I missed an 'until' there.
     
  9. LucidSymmetry606

    LucidSymmetry606

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    Mar 15, 2015
    I have another question related to the same project. Before making a new thread, I'll post it here along w/ a picture.

    Moving on to the transmitter, I'd like to put in a collapsible telescopic antenna to increase the range. In order to do so, I'd have to dremel out a little bit of the PCB. I have done this previously with another project with very successful results, however, I have some reservations about doing the same thing here. Take a gander at the pictures I've included to see exactly what I mean...

    Seriously. Thank you guys and gals for your help. :)
     

    Attached Files:

  10. chopnhack

    chopnhack

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    352
    Apr 28, 2014
    I know its been awhile, but I came across this - a little more complex than perhaps what you were thinking, but you might enjoy seeing it:

     
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