Hackaday Prize 2022: DIY Brushless Hand Cranked Generator

August 6, 2022 by Jenny List 12 Comments

A standard part of travel kit for the 2020s is now a battery pack — a hefty lithium-ion cell with onboard electronics for USB charging, that ensures all of our devices stay topped up while we’re out of range of a socket. But what happens when there is no handy mains supply to recharge it from? Step in [Chleba], with a hand cranked generator.

There are plenty of hand cranked generators to be found online, from tiny devices intended to top up a single phone to sturdy metal boxes intended for battery charging. This one differs from those in that most use a brushed DC motor as a cheap generator, while here that function comes from a stepper motor feeding a rectifier pack and thence a DC-to-DC converter. A step-up gearbox provides the necessary shaft speed, and a neat 3D-printed case rounds everything off.

The result is about as neat a generator as you could imagine, and would certainly be of use shoved into any off-grid backpack. Meanwhile it’s not the first we’ve shown you, we’ve even see one that could start a car.

The Rotary-X Engine Is A Revolution In Thermodynamics

February 15, 2021 by Kristina Panos 119 Comments

If you’re running an army, chances are good that you need a lot of portable power for everything from communications to weapons control systems. When it comes to your generators, every ounce counts. The smaller and lighter you can get them, the better.

Connecticut-based company LiquidPiston is developing a high-powered generator for the US Army that uses the company’s own rotary x-engine — a small, light, and powerful beast that sounds like a dream come true. It can run on gasoline, diesel, natural gas, kerosene, or jet fuel, and is scalable from 1 to 1,000 horsepower (PDF).

Co-founder and CEO Alex Schkolnik describes the design as a combination of the best parts of the Otto and Atkinson cycle engines, the Diesel, and the Wankel rotary while solving the big problems of the latter two. That sounds impressive, but it doesn’t mean much unless you understand how each of these engines work and what their various advantages and disadvantages are. So let’s take a look under the hood, shall we?

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Mobile Power From Cordless Tool Batteries

June 12, 2020 by Tom Nardi 26 Comments

For years, [Michael Davis] has been using a large lead-acid battery to power the electronic components of his custom Dobsonian telescope; but that doesn’t mean he particularly enjoyed it. The battery was heavy, and you always had to be mindful of the wires connecting it to the scope. Looking to improve on the situation somewhat, he decided to build an adapter for Ryobi cordless tool batteries.

[Michael] had already seen similar 3D printed adapters, but decided to make his the traditional way. Well, sort of. He used a CNC router to cut out the distinctive shape required to accept the 18 V lithium-ion battery pack, but the rest was assembled from hardware store parts.

Bent mending plates with nuts and bolts were used to create adjustable contacts, and a spring added to the top ensures that there’s always a bit of tension in the system so it makes a good electrical contact. This setup makes for a very robust connector, and as [Michael] points out, the bolts make a convenient place to attach your wires.

With the logistics of physically connecting to the Ryobi batteries sorted out, the next step was turning that into useful power for the telescope. A stable 12 V is produced by way of a compact DC-DC converter, and a toggle switch and fuse connect it to a pair of automotive-style power sockets. Everything is held inside of a wooden box that’s far smaller and lighter than the lead-acid monster it replaced, meaning it can get mounted directly to the telescope rather than laying on the ground.

If you want to build a similar adapter, the 3D printing route will potentially save you some time and effort. But we have to admit that the heavy-duty connection [Michael] has rigged up here looks quite stout. If you’ve got an application where the battery could be knocked around or vibrated lose, this may be the way to go.

DIY Power Station Puts Ryobi Batteries To Work

February 20, 2020 by Tom Nardi 35 Comments

Anyone with a few cordless tools has probably amassed quite a collection of batteries for them. If you’re a professional contractor, having a fleet of batteries you can swap out during the day’s work is a necessity. But if you’re just doing the occasional DIY project, those batteries are probably going to sit unused more often than not.

Looking to find alternative uses for his growing collection of Ryobi batteries, [Chris Nafis] has come up with a portable power station design that lets him put all that stored energy to use. With support for multiple charging standards and even an integrated work light, this device would be perfect to have around for power outages or to take with you on a camping trip.

Ryobi standardized on an 18 V battery a while back, so [Chris] is using a 10 A DC-DC buck converter to step that down to a more generally useful 12 V. From there he’s got a standard “cigarette lighter” automotive power connector which offers compatibility with a wide range of mobile devices such as small inverters or mobile radios. There’s also dual 2.4 USB “A” ports and a Quick Charge 3.0 compatible USB-C port for charging your mobile gadgets.

As an aside, this project is an excellent example of how powerful 3D printing can be when building your own hardware. Trying to make an interface for a Ryobi battery, without sacrificing a tool as a donor anyway, would be maddeningly difficult with traditional at-home manufacturing methods. But with a pair of calipers and a bit of time in your CAD package of choice, it’s possible to design and build an exact match that works like the real thing.

Which incidentally should make adapting the design to other battery types relatively easy, though editing STLs does pose its own set of unique challenges. A future improvement to this project could be making the battery interface a separate piece that can be swapped out instead of having to reprint the entire thing.

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Desperately Trying To Find A Use For The ChugPlug

March 7, 2018 by Tom Nardi 21 Comments

[AkBKukU] writes in to tell us of his experiments with the rather vile-sounding “ChugPlug”, an odd portable AC power bank designed for the express purpose of powering MacBook chargers. It would seem more efficient to simply build a DC power bank with a MagSafe connector to cut out the charger all together, but presumably there is some market for this particular niche device. Especially at the $15 they are currently selling for on Amazon.

Unfortunately, the ChugPlug that [AkBKukU] bought doesn’t seem to work. After some experimenting he found that it appears to only be outputting 80 VAC, obviously too low for many devices to function. But he reasoned that some things, like switch mode power supplies or restive loads, might still work. He just needed to come up with a way to plug them into the ChugPlug.

If his testing setup gives you a case of sweaty palms, you aren’t alone. He breaks open a dead MacBook charger to recover the female AC connector, and then solders that directly to an AC grounding adapter. The resulting pigtail lets [AkBKukU] plug in various AC loads while allowing him to probe the wires with his multimeter and oscilloscope.

Once he’s satisfied his hack works conceptually, that is, he’s able to plug arbitrary AC loads into this purpose-built battery pack, he follows up with a less dangerous looking adapter. Making use of the shell of the dead MacBook charger and what some might describe as a salacious amount of hot glue, he produces a compact and relatively safe looking device that will let him use his handicapped ChugPlug as a general purpose source of AC power.

It’s not the most elaborate portable power supply we’ve ever seen, and certainly wouldn’t be our first choice in an emergency, but at least [AkBKukU] managed to wring some use out of the thing in the end.

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