Simple Beetle Robot Uses Smoking Soldering Iron

As robot projects go, [creative ideas km]’s isn’t going to impress many Hackaday readers. Still, as an art project or something to do with the kids, it might be fun. But the reason it caught our interest wasn’t the actual robot, but the improvised soldering iron used in its construction.

The robot itself isn’t really autonomous. It is just a battery, a motor, and a switch. The motor vibrations make the robot scoot around on its bent copper wire legs. Some hot glue holds it all together, but the electrical wiring is soldered.

If you look at the video below, you’ll see the soldering is done with an unusual method. A disposable lighter generates a flame that hits an attached copper wire with a coil wound in it. The coil acts as a heat exchanger, and the wire becomes a soldering iron tip.

We doubt you’d want to use this kind of soldering iron for anything serious. Even a cheap iron would be more convenient. On the other hand, you might find this hacked soldering iron handy as a field expedient, especially when you don’t have access to AC power.

We doubt you’d improve this hack to make it ultrasonic, unless you let the robot straddle your lighter. Maybe you’d be better off with a homebrew iron that uses commercial tips.

34 thoughts on “Simple Beetle Robot Uses Smoking Soldering Iron

    1. Freeze framing at 1:14 it looks like the can has been cut-up and rolled into a cone with a thick wire (possibly a coat hanger) twisted around the cone from the ‘nozzle’ to a couple of nails attached to a block of wood that forms a handle of sorts. I think it then looks to have been blackened by soot, presumably from heating the ‘nozzle’ with the aforementioned lighter and then fresh (cold) glue is pushed in to the back of it manually.

        1. It’s not like glue guns aren’t dirt-cheap though, and this is inferior in a few ways that’d make it annoying to use. I just don’t get… why? I can see making something when you want something particular that doesn’t exist, or to save a lot of money, but this is just a bit pointless. Maybe if you really NEEDED a glue gun in a hurry and only had a can, a tea candle, some thick wire, wire bending tools, and a block of wood and the tools to shape it. And some screws, and a spring. And all the shops you bought all those tools from were closed. And you couldn’t just use some tape.

          THEN this might be a good idea. If you couldn’t just wait.

      1. Sounds cool, does anyone have a video? :3

        All kidding aside, i love these sort of things, ofc its subpar to a cheap soldering iron or gluegun, but the guy earns my respect for making them himself, most of us (calling ourself hackers tinkerers and whatnot) would just go to the store to acquire a new tool, theres something to be said for making your own.

      2. Neato, now lets parlay that into a candle powered extruder rigged to a 3D pantograph arrangement rigged with cotton spool pulleys and string that lets you 3D print from tracing a modelling clay mockup….

    1. I feel like I’m unproductive ???????????????????????????? I have too much fancy equipment, am drawn in too many directions, and end up magnetically suspended in the center.

      1. Your first statement is true, however i recently learned that your second statement is not. after years i finally bought a gaming mouse and by god thats a big difference vs the logitech ‘office-ish’ mouse i had before.

        Anyway OT: the guy deserves my respect for making his own tools, seems to me that thats a much more valuable skill then knowing how to use certain (store bought) tools

        1. THIS
          I enjoy the game of “me on a decrepit space station-can I fix it with what is on hand?” realm of tinkering and don’t have a lot of nice gear yet. That said, I will always remember the first time I used a temp controlled soldering iron vs my old pencil iron. It was like night and day similar to your gaming mouse.
          As folks that fix things all of the time it is nice to get something fully-functional every once in a while :)
          Great points, Olivier :)

          1. I tend to play the game of yes I could have absofreakinglutely got the SS Columbia back home. Man am I ever pissed about how that went down.

            By the way, flame powered tools won’t work great in free fall.

    1. I didn’t, but that’s interesting, ta!

      Half of them seem to be “make the flame bigger”, I think that’s basic-grade lighter hacking. Sure to be a couple of things to learn though.

      In response to the lower comment on blowtorches, you can buy adaptors that plug onto a disposable lighter, using it like a fuel tank. They, AFAIK, mix more air in, to give a blue blowtorchy flame. Like the cheap blowtorch windproof lighters you can buy.

      Once had a lighter with a green flame, had a little bit of wire with a blob of stuff suspended in the flame. Dunno what it was, but it never seemed to get any smaller. Also seen, online, ones with red, green, blue flames, with a little switch to change between the colours. Waiting for the day someone uses them to display video.

  1. I have a tiny butane torch that works fine for soldering heavier things. It could surely be used to heat up some hot glue. I remember reading the suggestion of slicing up the hot glue stick, then heating each bit with a soldering iron, so a torch would take care of that.

    I bought a better butane torch, it can actually stand up by itself. It included some tips, including a soldering tip, so I think I’d trust it for soldering circuit boards. I’ve yet to get around to filling it with butane, so I haven’t tried it yet.


  2. Unbelievably dangerous idea. Many years back, I tried making a mini blow torch with a Bic. I was very fortunate that I perforated the wall of the lighter by dropping it on the workbench and hitting something hot. Spectacular. Had I been holding it when it went, the damage would have been serious. I have heard tales of folks using a grinding wheel while having a Bic in a shirt pocket. One spark and third degree burns. I don’t think anyone should try this hack

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