Chainsaw/flashlight overkill

[Robbtoberfest] has earned our admiration with this crazy chainsaw powered spot light. It looks horribly dangerous, extremely inefficient, and woefully under engineered. We absolutely love it. This could be plucked from a video game or a movie and seems to be one UV bulb away from being the ultimate post apocalyptic zombie vampire Armageddon weapon. He has taken apart a chainsaw and attached it to a DC treadmill motor using a couple of bike sprockets and a chain. That DC motor then feeds a car headlight directly. As you can see in the video, when he cranks the gas, it shines pretty brightly. The unfinished nature of this is due to a deadline for a contest on instructables, so he plans on adding a protective cowl, some fancy paint work, and a voltage regulator down the road.

While this may be inefficient, it is certainly a step up from a steam powered spud gun.


  1. Nomad says:

    This is totally an anti-vampire weapon :D

    i think i’m going to make a 3D model of this

  2. HARaaM says:

    Will this thing charge a dead battery, on a hummer, 30 klicks north of the Green Zone?

  3. Sp`ange says:

    I like your thinkin, HARaaM. He could add a power strip or a car lighter adapter to power other things.

  4. Bleck says:

    Reminds me of Homer’s makeup gun.

  5. localroger says:

    Typical chain saw. He spends half the video trying to get it started, and it stalls while he’s demoing it. That’s not good when you’re blasting the oncoming zombies with your UV lamp mod.

  6. Viztro says:


  7. spyder_21 says:

    When I read the topic I thought kind of stupid. Then I seen what he did, then I thought that sweet. But then I noticed it was just made into a generator, not bad but he could of used something other than a chainsaw that stalls all the time.

    Good thinking though.

  8. Jake says:

    Holy balls!

    This is why I only buy STIHL and husqvarna chainsaws! No starting problems!

    Pretty rad. I think it would be better to mount the motor closer to the engine, maybe even couple them together and use no chain at all. He mentions the need for a voltage regulator- IMO, the best way to get 12V from this thing and keep the weight down would be to bolt a motorcycle/snowmobile/ATV stator right to the engine, and then use the accompanying voltage regulator. Better yet, use the headlight from the donor machine as well, if it uses a halogen bulb. That would cut the weight and size almost in half!

  9. bothersaidpooh says:

    hehe, nice mod.
    wonder if you could charge a phosphate lithium pack from this, would make a great emergency inverter for keeping your freezer/etc going in the event of a prolonged power failure (koff 2012solarArmageddon /koff) ;-)
    And the light makes a great addon for warding off the armies of the undead reanimated by said solar flare… sort of like Macgyver meets Dawn of the Dead. Film at 11.

  10. Cree says:

    socks and flip-flops? really?

  11. steaky says:

    Im not going to lie, I was expecting it to keep the chainsaw blade intact.
    also it looks like he was afraid to go full throttle maybe because of the bulb lifetime?

  12. barry99705 says:

    I was hoping for the same thing. I think he blew the light in the last few seconds of the video.

  13. Fili says:

    That’s the reason I use only electric chainsaws. They start at the push of a button. Much more reliable in case of a zombie attack. Well, as long as they don’t chew the wires and come in range of the wire. But aside from that, you’re set! :)

  14. BetaLyte says:


    Where would you publish such a model, please?
    Whould love one in a good resolution for a wallpaper or something.

  15. Jake says:

    It’s a generator, so yes, you obviously could charge batteries with it. The problem is that this is a rather inefficient setup, you would most certainly get a much higher efficiency from an actual generator. This unit retains the original clutch, and loses efficiency to the friction introduced by the chain and sprocket setup, among other things. This not to mention the fact that simply turning a motor shaft to create electricity is not very efficient (relatively speaking) to begin with.

    @steaky, barry
    He says that he doesn’t have a voltage regulator on it, that’s why he was trying to keep the RPM so low.

  16. Itwork4me says:

    What the guy didn’t show you is how he’s got multiple ones of these. Two for when he’s braking, two for turning, and two for hazards.

  17. Dan says:

    Wow what a piece of junk

  18. todd says:

    i find this completely impracticable and virtually useless as/is.not only is it very dangerous(a bike chain and no guard,and did you see that chain flapping)but i doubt you would be able to hold it up for more then a minute or two with all that crap hanging off the front of it.

    maybe it would have some sort of use as a generator you plug into,assuming he could get it to idle but even then you would have no way to increase the rpm to deal with the load put on it,so actually it’s a useless waste of a nice old homelite saw that probably would cut real nice with a tune up and new bar and chain.

  19. Olivier says:

    Can’t wait to see the next Texas Chainsaw Massacre movie !

  20. Diddle says:

    Noisiest. Flashlight. Evar.

  21. Hirudinea says:

    Bruce Campbell called, he wants his flashlight back.

  22. pixelwhip says:

    ironic thing is, he needs to add a torch to it so you can see what you are doing when you are trying to start it in the dark..

  23. Brad Hein says:

    This is a wonderful invention and I wish I had one to bring it to show and tell at my next outdoor bonfire or camping trip!

  24. cj says:

    > the ultimate post apocalyptic zombie
    > vampire Armageddon weapon.

    Ahahahahahahaha! I had this gestaltic moment as soon as I read that. Bon mot!

  25. gregman_1 says:

    What is it with all the HAD commenters lately bringing up the practicality of this
    stuff? I’m pretty sure that if you were looking for practicality, “Chainsaw Flashlight” was a pretty poor choice of article to click on.

  26. Ren says:

    Chainsaw vibration + incandescent filament = short bulb life

    A rechargeable battery on the output of the DC motor would help regulate the light output.

  27. Good-morning says:

    Pink-Panther ++ Willy E. Coyote Win!!

  28. Don says:

    hey why not use a car alternator!!!!!!
    Chevy ones (older) have built in Regulater

  29. steve0 says:

    pretty silly idea . lots of work for little gain . just my2 cents

  30. hyte says:

    makes me want to get an old chainsaw, car altenator and some expensive hi output white leds to have a mix of hi efficiency and low efficiency with a long bulb life and constant output.

    It probably would work well, though i hear xenon car lights are better than leds.

  31. jay says:

    This is cool because it isn’t green.. I like to be different

  32. ravyne says:

    You guys may be laughing, but I would have loved to have one of these when I was playing through Alan Wake!

  33. Jake says:

    To the guys thinking that you can use a car alternator, you CAN’T without initial current to start the generation process (you’d need a battery)

    You need what’s called a self-exciting alternator, they can be had but are rather uncommon as compared to a regular car alternator.

    It’s been a while since I’ve looked at the torque requirements for your average car alternator, but I suspect that your average chainsaw engine won’t *cut* it (heheheahahaha) unless you keep the power draw pretty low. A small stator is a much lighter, more compact solution and will still provide a decent amount of current.

  34. Jake says:


    Have you ever heard of a voltage regulator? They are pretty cool. You should check it out.

  35. todd says:

    i most certainly have…but why are you asking ME this?what relevance does it have to my comment other then it might run the light he has mounted without blowing it.i see no use for it as i see no use for this “device”.

    anywhere this monstrosity could be used i bet there would be atleast 100 or more other/better/smarter/MORE PRACTICAL and useful tools that could be used.

    like i said this is a horrible waste of a real nice old saw that would do it’s prescribed job 100 times better then to be used as a clunky loud unbalanced flashlight.

  36. Jake says:


    You said “but even then you would have no way to increase the rpm to deal with the load put on it”

    This led me to believe that you don’t realize how such a device works.

  37. Jake says:

    And you’re calling a homelite saw NICE? I’d call that a $5 garage-sale-worthy piece of crap!!!

    If it isn’t a stihl or husqvarna, I really don’t think it’s worth using unless you are one of those people that cuts up about 1 tree per year xD

  38. todd says:

    yes the homelites were good saws,in all honisty i would rather have an old homelite xl then a stihl but that’s not my main point,my main point is that this is a useless waist of equipment and time.

    it’s not even close to being ergonomic in any way and a lantern would be more practical in just about any situation then this not to mention the millions of other battery and other fueled lamps.

    unless you actually strap this thing to your back and hike a few miles with it i just don’t see you being in a situation where this would be your only source of light

  39. Jake says:

    It’s pretty rare to see a post on this site that could be described as ‘practical’, and that is the point – People make these things just to prove that they can. Yes, there is always a better way, and quite often these people are aware of that better way.

    If you’ve ever made some random gadget like this, you know that it *never* goes together the way you had it in mind (well, not unless you own a lathe, end mill, and about 1000 other shop/electrical tools and machines).

    Also, dude, hooked on phonics – Check it out :P :P :P

  40. Jake says:

    Oh, I forgot to mention that it helps to have an endless supply of cash and time – That also makes projects go together exactly as you imagined ;)

  41. Nitori says:

    This is how an ork would build a flash light.

  42. Eraser says:

    Go Jake.

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