Interesting Optics Make This Laser Engraver Fit In A Pocket

July 24, 2022 by 37 Comments

We’re going to start this post with a stern warning: building a laser engraver that can fit in your pocket is probably not a wise idea. Without any safety interlocks and made from lightweight components as it is, this thing could easily tip over and sear a retina before you’d even have time to react. You definitely should not build this, or even be in the same room with it. Got it?

Safety concerns aside, [DAZ] has taken a pretty neat approach to making this engraver, eschewing the traditional X-Y gantry design in favor of something more like the galvanometers used for laser projectors, albeit completely homebrew and much, much slower than commercial galvos. Built mostly of 3D-printed parts, the scanning head of this engraver uses a single mirror riding on an angled block attached to gimbals with two degrees of freedom. The laser module and mirror gimbals are mounted on a stand made of light aluminum so that the whole thing is suspended directly over a workpiece; the steppers slew the mirror to raster the beam across the workpiece and burn a design.

The video below shows it at work, and again, we have to stress that this is about as close to this build as you should get. It shouldn’t be too hard to add some safety features, though — at a minimum, we’d like to see a tilt-switch that kills power if it’s knocked over, and maybe some kind of enclosure. Sure, that would probably spoil the pocketability of the engraver, but is that really a feature valuable enough to risk your eyesight for?

If there’s a laser build in your future, please read our handy guide to homebrew laser cutter safety — before you can’t.

Continue reading “Interesting Optics Make This Laser Engraver Fit In A Pocket” →

Turn Drone Into A Large Propeller To Increase Hover Efficiency

July 24, 2022 by 42 Comments

Multirotor drones are significantly more popular than conventional helicopter designs for many reasons, which do not include efficiency. Making use of the aerodynamic effects behind this, [Nicholas Rehm] was able to significantly increase the efficiency of his experimental tricopter by turning it into one large spinning propeller.

Since aerodynamic drag is proportional to velocity, a small, high-RPM propeller will require more power to produce the same thrust as a large, low-RPM propeller. With this in mind, [Nicholas] built a tricopter that can rotate all three long arms together using a single servo, giving it very aggressive yaw control. By attaching a wing to each of the arms, it becomes a large variable pitch propeller powered by tip thrusters.Power draw graph

To measure the efficiency of the craft, a small lidar sensor was added to allow accurate PID altitude control. While keeping the drone at a constant altitude a few feet off the ground, [Nicholas] measured the power draw of the motors in a hover, and then let the drone spin around its yaw axis up to almost 5 rev/s.

At a spin rate of 4 rev/s, the power draw of the motors was reduced by more than 60%. Even compared to the drone without the added weight of the wings, it still used 50% less power to maintain altitude.

Since [Nicholas] hadn’t yet implemented horizontal position control while spinning, the length of each test run was limited by the wind drift. He plans to solve this, and also do some testing of the drone in horizontal flight, where the added airfoils will also increase efficiency.

We’ve featured a few of [Nicholas]’ flying machines here on Hackaday, including a foam F-35 VTOL and a cyclocopter. Most of his aircraft run his open source dRehmFlight flight stabilization, created specifically for hacking.

Continue reading “Turn Drone Into A Large Propeller To Increase Hover Efficiency” →

A ’70s TV With ’20s Parts

July 24, 2022 by 45 Comments

Keeping older technology working becomes exponentially difficult with age. Most of us have experienced capacitor plague, disintegrating wire insulation, planned obsolescence, or even the original company failing and not offering parts or service anymore. To keep an antique running often requires plenty of spare parts, or in the case of [Aaron]’s vintage ’70s Sony television set, plenty of modern technology made to look like it belongs in a machine from half a century ago.

The original flyback transformer on this TV was the original cause for the failure of this machine, and getting a new one would require essentially destroying a working set, so this was a perfect candidate for a resto-mod without upsetting any purists. To start, [Aaron] ordered a LCD with controls (and a remote) that would nearly fit the existing bezel, and then set about integrating the modern controls with the old analog dials on the TV. This meant using plenty of rotary encoders and programming a microcontroller to do the translating.

There are plenty of other fine details in this build, including audio integration, adding modern video and audio inputs like HDMI, and adding LEDs to backlight the original (and now working) UHF and VHF channel indicators. In his ’70s-themed display wall, this TV set looks perfectly natural. If your own display wall spotlights an even older era, take a look at some restorations of old radios instead.

Continue reading “A ’70s TV With ’20s Parts” →

Condemned Precision Capacitors Find New Home, Refuse To Become Refuse

July 24, 2022 by 12 Comments

Ah, the age old tradition of Dumpster diving! Sometimes we happen to spot something that’s not quite trash, but not quite perfect, either. And when [dzseki], an EEVblog.com forum user, spotted some high-precision capacitors being 86’d at their employer’s e-waste pile, [dzseki] did what any good hacker would do: took them home, tested them, and tore them down to understand and either repair or reuse them. They explain their escapades and teardown in this EEVblog.com forum post.

High-precision capacitors with RF connectors.

If you’re not familiar with capacitors, they are really just two or more plates of metal that are separated by an insulator, and in the case of these very large capacitors, that insulator is mostly air. Aluminum plates are attached with standard bolts, and plastic insulators are used as needed. There’s also discussion of an special alloy called Invar that lends to the thermal stability of the capacitors.

[dzseki] notes that these capacitors were on their way to the round file because they were out of spec, but only by a very, very small amount. They may not be usable for the precision devices they were originally in, but it’s clear that they are still quite useful otherwise. [dzseki]

Of course, Dumpster diving for cool parts is nothing new, and we’ve covered nifty projects such as this frankenmonitor bashed together from two bin finds.

Thank you [David] for the great tip, and don’t forget to leave your own in the Tip Line.

Hack Your Brain: Bionic Reading — Panacea Or Placebo?

July 23, 2022 by 17 Comments

In the Star Trek episode Space Seed, [Khan] famously said, “Improve a mechanical device, and you may double productivity. But improve man, you gain a thousandfold.” Most of our hacks center on the mechanical or electromechanical kind, but we do have an interest in safely improving ourselves. The problem is that most of us don’t want to mess with our DNA or have surgery, so it sort of limits our options.

We are always interested in less invasive hacks, so we certainly took note of Bionic Reading. However, a recent paper claims to debunk the claims of benefits. The company promoting the technology claims a Swiss University study showed that while the results were not clear, “the majority had a positive effect.” They also claim, anecdotally, that the technique can help those with dyslexia. What’s the truth? We don’t know, but it is an interesting discussion to follow.

If you haven’t seen it before, Bionic Reading — which, by the way, may not be free to use — is a way of using a dark font to emphasize certain key parts of words. For example, you can read this article using Bionic Reading. [Daniel Doyon] analyzed reading by 2,074 testers and found that participants actually read slower when using the Bionic Reading technique.

Continue reading “Hack Your Brain: Bionic Reading — Panacea Or Placebo?” →

Adding A Battery To Extend Speaker Life

July 23, 2022 by 14 Comments

Perhaps the weakest point in modern electronics when it comes to user servicability is the lifecycle of the batteries included from the manufacturer. Without easily replaceable batteries, many consumer goods end up in the landfill when they’re otherwise working perfectly. If you’d like to get more out of your devices than the manufacturer intends, you might have to go to great lengths like [Théo] did with his JBL speaker.

This was a Bluetooth device produced by JBL nearly a decade ago, and while the original device boasted several hours of battery life, after so many years of service, it was lucky to get a half hour before the battery died. To replace it, [Théo] removed the original battery and extended the case to be able to hold a larger cell phone battery. He also decided to use the original battery management circuit from the speaker with the new battery after verifying the voltage and chemistry were close enough to the original.

Since the phone battery is a proprietary Samsung device, [Théo] also decided to build a version that uses standard 18650 cells instead, although he prefers the slimmer design with the phone battery for his use case.  Straightforward as this build may be, it does go a long way to demonstrate the principle that if you can’t fix your devices, you don’t really own them.

Digital “Toy” Camera, Made For Tilt-Shift And Other Analog-Like Experimenting

July 23, 2022 by 5 Comments

Like many others, [volzo] loves playing with photography in a playful and experimental way. Oddball lenses, vintage elements, and building from kits is what that world looks like. But that kind of stuff is really the domain of film cameras, or at least it was until [volzo] created his Digital Toy Camera design. The result? A self-built, lomography-friendly digital camera that allows for all kinds of weird and wonderful attachments and photo shenanigans.

3D-printed mounts and magnetic attachment makes swapping parts a breeze.

To make a DIY digital camera that allowed that kind of play, the first problem [volzo] had to solve was deciding on an image sensor. It turns out that sourcing image sensors as an individual is a pretty cumbersome process, and even if successful, one still needs to write a driver and create things from the ground up. So, the guts of [volzo]’s creations use the Raspberry Pi and camera sensor ecosystem and M12 lenses, a decision that allows him to focus on the rest of the camera.

3D printing, a bit of CNC machining, and some clever design yields a “toy” camera: simple, inexpensive, and enabling one to take a playful and experimental approach to photography. The design files are available on GitHub, and there are some neat elements to the design. Magnetic mounts allow for easy swapping of lens assemblies, and a M12 x 0.75 tap cuts perfect threads into 3D-printed pieces for M12 lenses.

Heat-set inserts also provide robust fastening that can hold up to disassembly and re-assembly (and don’t miss that our own [Joshua Vasquez] has shared how best to design for and use heat-set inserts.)

[volzo] has a fantastic video to accompany his project; give it a watch (embedded below, under the page break) and see if you don’t come away with some inspiration of your own.

Continue reading “Digital “Toy” Camera, Made For Tilt-Shift And Other Analog-Like Experimenting” →