Need A Night-Light?

[Scott] created an LED candle in preparation for the big mac daddy storm (storms?) coming through.  Like millions of other people in Florida, he was stuck at home with his roommates when an oncoming hurricane headed their way.  Worrying about blundering about in the dark when the power inevitably went out, they set off to gather up all of the candles they had lying around.  Realizing the monstrous pile of candles and matches looked more and more like a death wish, the decision was made to create a makeshift light out of what components they had on hand.  Now, not having access to any outside sources for parts means that you are going to have a bare bones model.

That being said, this straightforward light only takes a couple of seconds to put together.  Jury rig a couple of AA or AAA batteries up, then slap on a resistor, LED, and jumper to get that sucker running.  Wrap electrical tape around the whole thing, or even try duct tape, whatever gets the job done.  A little paper hat on top of it will diffuse the light and bada bing, bada boom, you’re all done.  Generally though, soldering directly onto a battery is not a wise idea.  So, if you want to get fancy, perhaps a better alternative is to have a battery casing as shown below.

This LED candle is a clear option if your home isn’t a micro warehouse for electronic components (apparently it is frowned upon to clog up your garage for projects), and you have limited time.  However, if you have a number of extra minutes lying around before your windows blow in, see if you can top the brightest flashlight ever made (thus far). 

If you are lacking in some of the hardware used in either of these projects, just work with what you’ve got.  Here is another makeshift light that instead uses LED modules running from 12V DC power.  As long as you have a power source and LED of some sort, you can create light.  Half of the fun of being limited to working with random parts is figuring out what you can make with them.

Another notion of losing power that would make any sane person in this day and age flinch is the thought of their phone dying.  Portable battery packs are wonderful, but not everyone has one and we all know how easy it is to forget to make sure they’re charged up and ready for a disaster.  A handy way to get around this is by MacGyvering your own bad boy with a car USB charger, a pile of C cells, some paper clips, and tape.

Even the smallest of power outages can happen at any time, so it is better to be prepared than SOL.  What is your favorite emergency hack?


36 thoughts on “Need A Night-Light?

  1. I almost always have more fun getting the most out of the little I have rather than having an entire warehouse of parts and all the right tools. It’s like Junkyard Wars, but in my office :P

    1. This – limited materials always makes things more fun somehow.

      Also, FWIW you *can* solder to batteries (people weld tabs on them, after all) – I did a lot of it years ago to save money – but you have to be careful about it; scratching and heating with the very tip of a low-powered iron to get a small trace of solder down and then letting it cool, then reheat the solder to attach a wire.

      1. Scuff/burnish the battery tabs with an abrasive type ink eraser, then clean with your favorite electrical cleaner or rubbing alcohol.
        Then a grab cotton swab with a tiny dab of appropriate flux, to rub over the fresh cleaned areas.
        Do a quick, light, tinning of the surfaces and your ready for your pre-tinned wires.
        I do this this with almost all terminals. Makes for lot nice solder flow with less dwelling of the soldering gun.
        IF your scrounged wire is a bit less than shiny, Use a (clean) plastic scrubbing pad , like the Scotchbrite style, to pinc around, then pull the bare conductor through it a couple times. Usually the green pads from the kitchen cleaning dept will do just fine.
        Now do the same damp wipe with the cleaning rag and then flux & tin them.
        Happy soldering then!

        1. Less problem prone than soldering to the batteries themselves is to just solder (or in a pinch, but not nearly as long-lived, wrap) wires to brass pushpins, which can be pressed into wood. Even say, paint stirrers, which could be taped, rubberbanded or velcro-stripped together on either side of your alternating battery array. Now you’re set up to replace batteries in your pack rather than have to reassemble the pack entirely from scratch each time.

          However, a far superior battery holder can be made if you have a suitable diameter of PVC pipe (as commonly used for garden irrigation in the USA). This will provide a more reliable battery contact, be more resistant to the elements, and be easier to replace cells in. US pipe sizing 1/2″ works for AA cells, 1″ for C, 1 1/4″ for D. You can make do without PVC endcaps, but it all goes together nicely if you use them. Measure off an appropriate length of PVC for the number of cells you want to run, and add perhaps half an inch (or an inch if you’re trying to make do without end caps). If no end caps. drill a hole clear through the pipe about 1/4 to 3/8″ from one end Run a nail, cotter pin, or even solid conductor (12 AWG would work nicely) copper wire through, and bend it over so it stays in place. If using caps, drill suitable diameter holes through the middle of the ends of the caps and thread in your screw or bolt (I find a machine screw into a slightly undersized hole works great), and solvent glue the cap to the pipe at one end. Stack your batteries in, and press-fit the other cap on. The batteries may have play – just gently tighten the screw at one or both ends to take up the slack, and you’re ready to make connections to the two terminals. Label + and – ends and the number and size of battery (as a rule, I solvent the negative side). If you use machine screws, before driving them into the endcaps, you could thread a nut onto each machine screw as a mechanism for tightening up on some wire wrapped around the screw. If so equipped, you could drill a hole through the side of the screw or bolt near the head, which you could pass a wire through and then tighten the nut down on that to trap it. Otherwise, alligator clip, solder (best done before threading into the PVC), or snugly wrap wire onto the terminals. If you’re doing without end caps, the removable end can either be carefully cross drilled and pinned similar to the closed end, or you could use a tight fitting dowel with a screw or nail run through it to make contact with the terminal. Actual cost is negligible, but if you deal with any irrigation/repair at home, all the parts are things you should have on hand. It’s a useful thing to do with short scrappy bits of PVC, including pieces taken out due to repair/rework. IMO, the only real downside is that if you have a significant number of cells, your battery pack will be long (but still mechanically sound) and not near as compact as an alternating array, though you could make several shorter pipes and wire them in series, strapping them together in a bundle, though in my own exploits 3 or 4 cells in series is usually all one is looking for.

          For making connections to individual batteries, you can solder lead wires to pieces of copper tape and then encapsulate small (like 4 or 5mm diameter) neodymium magnets with the adhesive facing in towards the magnet. Do not wrap and then solder – high heat from the soldering will nearly instantly demagnetize the cells — and for this reason, keep the batteries away while you’re soldering, lest they fly up and affix themselves briefly to the soldering iron like a moth to a flame. Once assembled, these readily snap onto the terminals of most alkaline cells, although some astoundingly cheap ones seem to have the caps made out of something less than steel.

          My own use of pushpins is actually for making battery replacements (the recently posted CR2016/32 emulator PCB is along the same lines). I laser cut (yea, not a typical field expedient) acrylic discs and keyed centre shafts with holes in them for wire strain reliefs. These are solvent glued together into small battery analogs and a pushpin is heated and pressed into one or both ends and soldered to wire which runs off to the new supply. One can use a suitable chunk of wooden dowel (cut piece of small tree branch driven through your window by the storm perhaps) or other material as well. These serve to allow external power (wallwart, or a rechargeable with buck/boost, etc) to be provided to a device designed to run from batteries only, without modification to the host device. Making a small notch in the battery hatch for wires to pass through is helpful though.

          A switchmode regulator (or even a linear, but I don’t recommend that if you have an option because they’re far less efficient) can be soldered between a pair of alligator clip leadwires, so you can clip it to a higher voltage battery supply – such as a 12V automotive battery – to supply power to devices which run from a lower voltage. Even for prototyping, I have some 9V clips with either 5 or 3V3 regulators inline to the wiring (along with a switch so they’re not regulating when not in use), which is a handy way to use up 9V cells retired from your smoke or CO2 detector.

    1. It’s not anything new, but it’s in the hacker spirit. I don’t know about you, but something about even simple disaster scenario hacks gets cogs turning in my head. It was a cute article.

      1. Yeah, but taping some shit up to a battery isn’t anything we haven’t all thought of ourselves, and wouldn’t do if we were stuck.

        BTW I’d be surprised if that car USB charger needs a full 12V to run. Probably 7.5 or even 6 volts would do. It’s either a linear dropper (likely if it’s cheap) or a buck convertor, either way it’ll run on a lot less. No point throwing precious batteries at generating tiny amounts of heat.

        Meanwhile in reliable-world there’s torches. They’re very cheap. I’d be surprised if most people planning for a disaster didn’t have a few around the place.

      1. Don’t blame me, either. I sent in a tip about the recent breaking of the Dallas DS5002FP protection on a set of arcade games which until now have been unable to be emulated, and as far as I can tell, nothing ever materialized of it. I practically wrote the opening paragraph of the article.

        The Hackaday editors and other people always reply to the effect of “well send your cool projects and such into the tip line”, but it’s pretty demotivating when one isn’t even given a reason why a tip is rejected.

    2. It’s an expedient post on emergency power and light, during a particularly nasty hurricane season. Not all Hackaday posts feature incredible hacks, sometimes they feature the hacks you might need.

    1. I was Lauren’s editor on this one, and I read it as a quick piece on expedient power and light hacks. Yes, of which hooking up an LED to a battery is one, get over it. Given what’s crossing my TV screen atm from the Caribbean or Mexico, the wider topic is not entirely out of scope.

      1. Perhaps “common sense” should prevail, and prioritizing time urgent tasks in a life / property threatening environment would be more prudent. Living in a known hurricane zone (that’s why they have rigorous new FL building codes in place), it would have been less Darwinian for the ‘hacker’ (hummph !) to obtain – in ADVANCE – emergency supplies! (of which lighting equipment would be a staple…. how much is a stupid flashlight at the dollar store ? $1.00 ?).

        What’s his next trick ? house on fire ? let’s ‘hack’ together a fire extinguisher ! (never mind about having one around just in case – or calling the fire dept – maybe hack together a “zero phone” first ?)…. “SMH” !!!

        1. “in ADVANCE” … of course, like planning ahead and jumping into our private Lear Jet and fly to one of our safe homes spread all over the world … because everybody has them!

          Nah, no fun on that.

  2. Wikipedia says alkaline c cells can hold up to 8000 mAh, does that mean that 8 of them hooked up to that usb charger like that hold as much as 64000 mAh? Or is there some other math involved i’m not aware of?

  3. I feel like the people worried about candles the ones who have never used one. There are many, many perfectly good and easy ways to mitigate the well known dangers of an open flame. Tile doesn’t burn and neither does any form of countertop made out of stone, concrete, and other non-flammable materials. Drywall is by nature flame resistant and many many products contain or are treated with flame retardant. The important thing is to not leave the open flame out of sight/unattended. People managed to get on mostly without incident for centuries with oil lamps, candles, and eventually gas powered lights.

    That’s not to say that an LED device wouldn’t be handy. FWIW, exposed batteries that are shorted/connected that have exposed wires could be a small fire risk too.

    1. And there are “many, many perfectly good and easy ways to” – use a slide rule …. but does any practicing engineer use one ? Candles are an anachronism from days gone by (much like the slide rule). Using any sort of open flame in a post disaster scenario is begging for fate to unleash her fury on the hapless soul who dare tempt her. Natural gas leaks in collapsed structures are fairly common hazards. So the use of candles after – say an earthquake – is begging for a Darwin Award.

    2. Ah yes. Nothing like the thoughts of LiPo cells and a million chunks of broken glass and bits of lumber with nails and screws, sheet metal, etc.
      All being tossed together by hurricane force winds. :^D

      There. That thought should help you to sleep better.
      Sounds like a story for the local “Nit-Witness” news severe storm alert channel.

  4. Hey can I enter my rolling some old printer paper around AA cells to I can stick them in my C cell flashlight in a pinch for a hack a day entry? I made a bunch of them a few years ago and I still use them. If you have not hit on this yet, C cella and AA’s are the same length, and you can make a mandrel to hold AA’s in place of C’s. In LED flashlights (torches for you guys overseas) they work really well.

      1. You can get close enough with a piece of 1/2″ PVC pipe, though I generally just avoid using too many things that use C or D cells in the first place — devices which use C and D tend to have higher current demands.

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