Sometimes, a person has a reason to track a target. A popular way to do this these days is with a camera, a computer, and software to analyze the video. But, that lends itself more to automated systems, like sentries. What if you want to be able to target something by “painting” it with a laser?
That’s exactly what [Jeremy Leaf] wanted to do, and the results are pretty impressive. He was able to track a .06 milliwatt laser at 2 meters. His design does this using three photodiodes in order to determine the position of a laser spot using triangulation.
Once the location of the laser spot has been determined, it can either simply be reported or it can be tracked. Tracking is achieved with a gimbal setup which updates quickly and accurately. Of course, it can only track the laser if the laser has something to be projected upon. If you need to track something in open 3D space, there are alternatives that would be better suited to the task.
[Scott Harden] is working on a research project involving optogenetics. From what we were able to piece together optogenetics is like this: someone genetically modifies a mouse to have cell behaviors which can activated by light sensitive proteins. The mice then have a frikin’ lasers mounted on their heads, but pointing inwards towards their brains not out towards Mr. Bond’s.
Naturally, to make any guesses about the resulting output behavior from the mouse the input light has to be very controlled and exact. [Scott] had a laser and he had a driver, but he didn’t have a controller to fire the pulses. To make things more difficult, the research was already underway and the controller had to be built
The expensive laser driver had a bizarre output of maybe positive 28 volts or, perhaps, negative 28 volts… at eight amps. It was an industry standard in a very small industry. He didn’t have a really good way to measure or verify this without either destroying his measuring equipment or the laser driver. So he decided to just build a voltage-agnostic input on his controller. As a bonus the opto-isolated input would protect the expensive controller.
The output is handled by an ATtiny85. He admits that a 555 circuit could generate the signal he needed, but to get a precision pulse it was easier to just hook up a microcontroller to a crystal and know that it’s 100% correct. Otherwise he’d have to spend all day with an oscilloscope fiddling with potentiometers. Only a few Hackaday readers relish the thought as a relaxing Sunday afternoon.
He packaged everything in a nice project box. He keeps them on hand to prevent him from building circuits on whatever he can find. Adding some tricks from the ham-radio hobby made the box look very professional. He was pleased and surprised to find that the box worked on his first try.
Everyone wants their prototypes to look polished, as opposed to looking like 3D-squirted weekend afterthoughts. The combination of Delrin and a Laser Cutter make this easy, especially if you learn a few tricks-of-the-trade that will make your assemply pop, both functionally and aesthetically.
If you’re just getting started in this domain, let me introduce you to two classic techniques for laser-cut prototypes: puzzle-piecing and the T-nut-slotting. While these techniques are tried-and-true, I hope, fearless reader, that they’ll leave you hungry for something cleaner, something more refined. If that’s the case, read on!
Laser-cut plywood boxes are cool. Don’t believe me? Take a look at the free projects out there for people to get started with when they get a laser cutter – it’s obviously a popular genre of project. Laser cut plywood boxes with combination locks are even cooler, especially when the combination is entered on four separate number selectors, on four sides of the very same box.
The LaserWeb project recently released version 3, with many new features and improvements ready to give your laser cutter or engraver a serious boost in capabilities! On top of that, new 3-axis CNC support means that the door is open to having LaserWeb do for other CNC tools what it has already done for laser cutting and engraving.
LaserWeb3 supports different controllers and the machines they might be connected to – whether they are home-made systems, CNC frames equipped with laser diode emitters (such as retrofitted 3D printers), or one of those affordable blue-box 40W Chinese lasers with the proprietary controller replaced by something like a SmoothieBoard.
We’ve covered the LaserWeb project in the past but since then a whole lot of new development has been contributed, resulting in better performance with new features (like CNC mode) and a new UI. The newest version includes not only an improved ability to import multiple files and formats into single multi-layered jobs, but also Smoothieware Ethernet support and a job cost estimator. Performance in LaserWeb3 is currently best with Smoothieware, but you can still save and export GCODE to use it with Grbl, Marlin, EMC2, or Mach3.
We recently shared a lot of great information on safe homebrew laser cutter design. Are you making your own laser cutting machine, or retrofitting an existing one? Let us know about it in the comments!
FreeCAD is a fairly sophisticated, open-source, parametric 3D modeler. The open-source part means that you can bend it to your will. [Alexandre] is working on a module that lets him easily add tabs, finger joints, and t-slots to models (YouTube link, embedded down under).
Right now the plugin is still experimental, but it looks usable. In the video demo, [Alexandre] builds up a simple box, and then adds all manner of physical connective pieces to it. You’ll note that the tabs look like they’re pieces added on to the main face — that’s because they are! He then exports the outlines to SVG and erases the lines that separate the tabs from the sides, and hands these files off to his laser cutter. Voilà! A perfect tab-and-t-slot box, with only a little bit of hand-work. ([Alexandre] mentions that it’s all still very experimental and that you should check out your design before sending it to the laser.)
We weren’t going to run this one, because, well, it’s just ridiculous. But enough of you have browbeat us by sending in tips to the tipline that we’re going to capitulate. We’re not going to name you all by name, because really, you should be ashamed of yourselves. But you know who you are!
[Styropyro] does a lot of crazy things on YouTube. We really liked his “stuff in a microwave oven” series. He’s also obsessed with lasers and popping black balloons. So he took the laser heads out of four DLP computer projectors (the ones with 24 of those 1.5W Nichia diodes) and combined them. Yup, 200W of 405 445nm blue.
Then he just straps them together and passes them through a lens. It’s not a tight beam, but this thing is really bright. Even though the beam is very loosely focused, it burns stuff. That’s about all you can say. Lots of laser. Boy Howdy!
OK, there, we ran it. Don’t do this at home. It doesn’t require much finesse, and it’s going to get someone blind. Much better to expend your efforts on something more civilized like a projector. At least then you can play vector games on the wall. And stay off my lawn!!! (Kids these days…)
For those that do want to burn stuff, [Joshua Vasquez] published an article yesterday about building a safe laser cutter… much more worth your energy than anything billed as a laser bazooka.