In the video game Metro 2033 and its subsequent sequels, players fight their way through a post-apocalyptic version of Russia using improvised weapons and tools cobbled together from the sort of bits and bobs the survivors of a nuclear war might be able to scavenge from the rubble. One of the most useful devices in the game is known as the “Universal Charger”: a hand-operated dynamo that the player must use periodically recharge their electrical devices.
As demonstrated in the video after the break, his charger manages to produce enough energy to light an LED on each squeeze of the trigger. Though if we were packing our gear to go fight mutated beasties in alternate-future Moscow, we might look for something with a bit more kick.
Beyond the 3D printed parts, the charger uses a couple short pieces of 8 mm rod, a NEMA 17 stepper motor, and a one-way bearing that’s usually used for pull starting small gasolene engines.
How many of you plan to build a wind-powered generator in the next year? Okay, both of you can put your hands down. Even if you don’t want to wind your coils manually, learning about the principles in an electric generator might spark your interest. There is a lot of math to engineering a commercial model, but if we approach a simple version by looking at the components one at a time, it’s much easier to understand.
For this adventure, [K&J Magnetics] start by dissect a commercial generator. They picked a simple version that might serve a campsite well, so there is no transmission or blade angle apparatus to complicate things. It’s the parts you’d expect, a rotor and a stator, one with permanent magnets and the other with coils of wire.
The fun of this project is copying the components found in the commercial hardware and varying the windings and coil count to see how it affects performance. If you have ever wound magnet wire around a nail to make an electromagnet, you know it is tedious work so check out their 3D printed coil holder with an embedded magnet to trigger a winding count and a socket to fit on a sewing machine bobbin winder. If you are going to make a bunch of coils, this is going to save headaches and wrist tendons.
They use an iterative process to demonstrate the effect of multiple coils on a generator. The first test run uses just three coils but doesn’t generate much power at all, even when spun by an electric drill. Six windings do better, but a dozen finally does the trick, even when turning the generator by hand. We don’t know about their use of cheap silicone diodes though, that seems like unintentional hobbling, but we digress.
We all know that hacker that won’t use a regular compiler. If he’s not using assembly language, he uses a compiler he wrote. If you don’t know him, maybe it is you! If you really don’t know one, then meet these two. [Nathan Fuller] and [Andy Baldwin] want to encourage you to write your own 3D slicer.
Their post is very detailed and uses Autodesk Dynamo as a graphical programming language. However, the details aren’t really specific to Dynamo. It is like a compiler. You sort of know what it must be doing, but until you’ve seen one taken apart, there are a lot of subtleties you probably wouldn’t think of right away if you were building one from scratch.
We think this hand cranked robot design is nothing short of absolute brilliance. The toy is remote-controlled through a short section of wire. It can drive forward and turn, but not at the same time. Still that’s impressive considering it uses no battery or power supply and, of the two servo motors, only one is actually in the robot itself.
The second servo, which is visible to the right, acts as a dynamo. When you crank it electricity is generated. The inputs of that servo are connected to the inputs of the one in the robot to power it. If you crank in one direction the colorful toy will drive forward. But there is a one-way catch on one of the side wheels so when the servo is cranked backward the little guy actually executes a reverse turn. The magic of building a project like this is perfect for a weekend activity with the kids. Don’t miss the demo embedded after the jump.
[Scott Nietfeld] built a charger from a Dyna-flex wrist exerciser. We hadn’t heard of a these gyroscopic devices before but once we saw the promo video (embedded after the break) we realized that this is the kind of thing that infomercials were made to sell. [Scott] knew the internals spun to fairly high RPM and figured that adding a few magnets on the inside and coils on the outside would turn this thing into a generator. Four rare-earth magnets fit the bill, with two external coils feeding a rectifier and linear regulator. Below you can see his demonstration video where he takes the orb apart, then spins it up, generating 250 mA at about 7.5 volts to drive the regulator and charge a cellphone. Not bad!
[Garote] has been extremely busy. Busy building an electrical system into his bicycle, and even busier writing a monumental post about it. He covers an impressive range of topics, starting with the goal of adding a generator, battery, charging system, lights, and accessories to the bike. From there he clicks off one thing at a time, researching and ordering a wheel with a Dynamo hub for the generator, assembling and testing the cells of his battery, choosing the controller board for the charging system, and designing the accessory circuits like the iPhone charger above. If he adds too much more to the two-wheeled rig he’s going to have to plan a big road trip with it.