Building A 1.4W Laser Pointer In A Tiny Housing

Laser pointers were cool for about 30 seconds when they first came out, before becoming immediately passé and doing absolutely nothing to improve the boss’s quarterly reports presentation. However, just as with boom boxes and sports cars, more power can always make things better. [Styropyro] was unimpressed with the weak and unreliable laser pointers he’d sourced from eBay, so gutted one and began a fresh build.

After fiddling with some basic 1mW eBay green lasers, [styropyro] had some fun turning up the wick by fiddling with the internal trimpots. This led to the quick and untimely death of the cheap laser diodes, leaving a compact laser pointer shell ripe for the hacking.

To replace the underwhelming stock components, [styropyro] chose a Nichia NDG7475 high-powered laser diode, fitting it into a small heatsink for thermal management. Current draw was far too high to use the original switch, so the stock housing’s button is instead used to switch a MOSFET which delivers the full current to the laser driver. To reach the higher output power of 1.4W, the laser diode is being run over specification at 2.3 amps. All this current draw would quickly overwhelm standard AAA batteries, so a pair of lithium polymer 10440 batteries are substituted in to do the job.

The build shows that with clever parts selection and some easy hand soldering, you too can build an incredibly dangerous laser pointer at home, that fits neatly in your shirt pocket. Alternatively, you might prefer something on the larger scale. Video after the break.

 

33 thoughts on “Building A 1.4W Laser Pointer In A Tiny Housing

  1. Neat, but mine is smaller and more powerfull :P (1.65W peak)
    (I didnt build it tho, i bought it from some bloke near me i found on laserpointerforums[dot]com)

    Not saying this isnt cool or anything (quite the opposite actually) just that i thought 1-2W portable lasers where quite common these days? mines like 7 years old?

    Again, no disrespect, neat laser ^^

    1. Lasers are by design bad for you, the wavelength doesnt really change anything about that (so like, regardless if it emits more or less IR, its still the same total power output, still the same chance on doing damage)

      1. Yes, but it affects behaviour.

        IR (and UV) is kinda more dangerous because you don’t realise how bright it is.

        When people see a super-bright laser they automatically treat them a bit more carefully, but when they see a dim green one and don’t see the far brighter IR/UV component, they don’t realise how powerful it is and won’t be as cautious.

      2. The issue is one of safety, you buy laser googles to protect against the advertised green light wavelength but unbeknownst to you you’ve got a load of IR pouring out the end that you weren’t aware of. Laser safety googles are usually only deign for a specific wavelength, decent board band laser googles get really expensive.

    2. This one is a single-mode (direct) green diode as opposed to an IR+divider/doubler setup. These are new in the last few years, and won’t have the IR leakage problem b/c they don’t make the IR in the first place.

      I just looked, and you can get low-power direct greenies for $50 or so. The one demonstrated here is a $300 diode.

      It’s alluded to in the video, but these have been much anticipated for the last decade, since the high-power blues came out. This makes a 1+1+1 W RGB somewhat affordable.

      Wait five more years, and you’ll be buying the 1.5 W greens for $50 and a full-color multi-watt laser projector for a few hundred. Fun times. :)

  2. I have the opposite problem, most of the ebay laser pointers I have come across are sold as 5mw, but are actually 10+mw when they arrive. The 660nm ones seem to be the most egregious offenders, I have yet to find one which puts out under 100mw… The result is that they are painfully bright when used for laser pointing, and require disassembly and modifications to tone them down to a reasonable brightness. Some of them can be corrected with adjustment of the pot, but most of the ones I have come across so far were uncomfortably bright even at minimum current and required tweaking the onboard resistors to get to a reasonable brightness. I found that the optimal brightness is ~1mw for 520nm at the peak of the eyes sensitivity, 3-5mw for the various shades of blue (450-480) and red-orange (630-640), and about 10mw for the colors at the edge of human vision–ultravolet/violet/deepred (365, 405, 660, etc). For safety I keep the invisible ones (700nm+) at 1mw which is usually plenty to make it through a cell phone camera IR filter or light up a phosphor type IR viewer card.

      1. To put it into perspective, the (unfocused) spot from this laser is about 1000x more intense than sunlight, and when you consider that it is also nearly at the peak of human vision sensitivity compared to the blackbody spectrum of the sun it will appear to be over 10,000x brighter than sunlight to the eye. I can’t imagine any application where such an intense static spot would be desirable to look at.

        Such ‘laser pointers’ really are only useful for their ‘setting things on fire’ properties.

      1. “can you clarify whether you’re scaring them off or shooting them out of the sky?”
        If shooting them from the sky, can you provide us with the ebay link to the surplus laser guided munitions you use. Just asking for a friend you understand.

  3. This one is _definitely_ a don’t-do-it-at-home-unless-you-know-about-laser-safety project.

    Still, in place of a non-constructive statement that it’s dangerous, it would be a lot more informative if it included a “how to do this safely” instead. Mains electricity is deadly, yet we know how to take appropriate safety precautions. The same would be good for lasers.

    Things I would have liked to see in the video: beam termination or even some mention of reflective surfaces. With a watt or so, you really need to think about containing the beam. You really don’t want to get even a 1/10th of this one in the eye.

    Styro, maybe you could do a video on laser safety?

    Awesome diode, though. :)

    1. Elliot, can Hackaday stop frequenting the same bits of Youtube/ Internet I’ve already looked at ;-)
      Seriously though much of what you are putting up these days is what YT and their algorithms are offering me except a month or more earlier. Not sure if I’m a leader of fashion or this is a common event amongst Hackaday’s readers.

      Again maybe we are all focused through the same traffic via the algorithms but it kind makes Hackaday like the repeats on TV not original programming !

      1. No, we can’t! And here’s why. (Warning, serious answer to an offhand question!)

        YT does a decent job at profiling you based on what you watch, and they’re ready to serve you a stream of recomendations before the video is even made public, b/c they have the inside angle. But their algorithms aren’t really all _that_ good. They still try to show you perpetual motion machines just b/c you like machines, for instance. Don’t get me started on the flat earth thing.

        We, however, are made of real people with (possibly similar) interests to yours, and if I dare say it, pretty good taste in hacks. But we watch, collectively, _a ton_ off videos before we recommend one to you. Things can get even worse if we have a sudden barrage of truly awesome hacks to write up. In short, we have a much higher signal to noise ratio than YT, but to do this takes time, so we’re naturally slower than them.

        Thus: if you value _your_ time, check out Hackaday. :) Where real live humans / hackers have spent the time filtering out the crap for you.

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