Ode To The TL431, And A LiFePO4 Battery Charger

January 8, 2016 by Elliot Williams 85 Comments

Nerd Ralph loves cheap and dirty hacks, and for that we applaud him. His latest endeavor is a LiFePO4 battery charger that he made out of parts he had on hand for under $0.50 US. (Although we think he really made it for the fun of making it.)

The circuit is centered around a TL431 programmable shunt regulator, which is an awesome and underrated chip in its own right. If you don’t know the TL431 (aka LM431), you owe it to yourself to fetch the datasheet and pick up a couple with your next electronics part order. In fact, it’s such a great chip, we can’t resist telling you about it for a minute.

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CES: Self-Flying Drone Cars

January 8, 2016 by Brian Benchoff 36 Comments

CES, the Consumer Electronics Show, is in full swing. Just for a second, let’s take a step back and assess the zeitgeist of the tech literati. Drones – or quadcopters, or UAVs, or UASes, whatever you call them – are huge. Self-driving cars are the next big thing. Flying cars have always been popular. On the technical side of things, batteries are getting really good, and China is slowly figuring out aerospace technologies. What could this possibly mean for CES? Self-flying drone cars.

The Ehang 184 is billed as the first autonomous drone that can carry a human. The idea is a flying version of the self-driving cars that are just over the horizon: hop in a whirring deathtrap, set your destination, and soar through the air above the plebs that just aren’t as special as you.

While the Ehang 184 sounds like a horrendously ill-conceived Indiegogo campaign, the company has released some specs for their self-flying drone car. It’s an octocopter, powered by eight 106kW brushless motors. Flight time is about 23 minutes, with a range of about 10 miles. The empty weight of the aircraft is 200 kg (440 lbs), with a maximum payload of 100 kg (220 lbs). This puts the MTOW of the Ehang 184 at 660 lbs, far below the 1,320 lbs cutoff for light sport aircraft as defined by the FAA, but far more than the definition of an ultralight – 254 lbs empty weight.

In any event, it’s a purely academic matter to consider how such a vehicle would be licensed by the FAA or any other civil aviation administration. It’s already illegal to test in the US, authorities haven’t really caught up to the idea of fixed-wing aircraft powered by batteries, and the idea of a legal autonomous aircraft carrying a passenger is ludicrous.

Is the Ehang 184 a real product? There is no price, and no conceivable way any government would allow an autonomous aircraft fly with someone inside it. It is, however, a perfect embodiment of the insanity of CES.

Add Seinfeld Bass Riffs To Any Doorway

January 8, 2016 by Elliot Williams 19 Comments

It’s not the most involved hack we’ve seen this week, but it’s definitely creative and made us laugh. [Grant] and some friends were joking around about how cool it would be to have sitcom-style entry music fire off every time someone came in through a door, but in real life. You know, like everyone wants to have their own theme music? This is the same idea, but the Seinfeld equivalent. (Video embedded below the break.)

A few simple parts later (Arduino, MP3 shield, magnetic door reed switch) and a tiny bit of code to randomize which bass riff plays, and it’s a done deal. Like we said, it’s not rocket science, but it’s a humorous addition to what looks like a well-stocked game room. (Is that a Joust console we see?)

For even greater comic effect, why not add Seinfeld bass riffs to your skateboard ramps?

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Make PCBs With DLP, OMG!

January 7, 2016 by Elliot Williams 48 Comments

There’s so many ways to skin the home-fabrication-of-PCBs cat! Here’s yet another. [Nuri Erginer] had a DLP projector on hand, and with the addition of some reducing optics, managed to turn it into a one-shot PCB exposer.

If you’ve ever used photo-resist PCB material before, you know the drill: print out your circuit onto transparency film, layer the transparency with the sensitized PCB, expose with a UV light for a while, dissolve away the unexposed resist, and then etch. Here, [Nuri] combines the first three steps in one by exposing the board directly from a DLP projector.

The catch is that the projector’s resolution limits the size of the board that you can make. To fab a board that’s 10cm x 10cm, at XGA resolution (1024×768), you’ll end up with a feature size of around 0.004″ in the good direction and 0.005″ in the other.

For DIP parts, that’s marginal, but for fine-pitch or small SMT parts, that won’t do. On the other hand, for a smaller board, optimally one in the same 4:3 ratio, it could work. And because it exposes in one shot, you can’t beat the speed. Cool hack, [Nuri]!

When you need more precision, strapping a UV laser to an accurate 2D robot is a good way to go, but it’s gonna take a while longer.

The Most Plausible Apollo Moon Landing Conspiracy Ever Devised

January 6, 2016 by Brian Benchoff 247 Comments

The Internet is polluted with craziness, and there is no better example than YouTube. If you’ve ever wondered what would happen when you give everyone on the planet the power to show everyone else on the planet their innermost thoughts, desires, and insane ramblings, you need only look at YouTube.

One of the biggest offenders of incoherent ramblings is the subject of spaceflight. Simply search ‘space shuttle’ on YouTube, and you’ll find accusations of the crew of Columbia being abducted by aliens. Crazy, incoherent, and somewhat insulting. Accusations of a moon landing conspiracy are unavoidable in the ‘related videos’ section and are similarly filled with videos from people with either a tenuous grasp of reality or too much time on their hands.

A broken clock is right twice a day, a broken calendar is right every twenty-eight years or so, and every once in a while, simply from the volume of videos on the subject, one conspiracy theorist will present a new and novel idea. Here we present perhaps the only moon landing conspiracy theory that makes sense, is consistent with physical laws, and that may actually be true.

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The 3D Printers Of CES

January 6, 2016 by Brian Benchoff 65 Comments

CES, the Consumer Electronics Show, is in full swing. That means the Hackaday tip line is filled to the brim with uninteresting press releases, and notices that companies from the world over will be at CES.

3D printing has fallen off the radar of people who worship shiny new gadgets of late, and this is simply a function of 3D printing falling into the trough of disillusionment. The hype train of 3D printing is stuck on a siding, people are bored, but this is the time that will shape what 3D printing will become for the next ten years. What fascinating news from the 3D printing industry comes to us from CES?

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Ten Mile Raspberry Pi WiFi (with A Catch)

January 5, 2016 by Al Williams 57 Comments

How would you like to have a WiFi connection that covers 10 miles? Or how about an even wider network made up of a mesh of multiple nodes? It is possible, but there is a catch: you probably need a ham radio license to do it (at least, you do in the United States).

What makes it possible is the realization that conventional WiFi channels 1-6 are inside an existing US ham band. That means (if you are a ham) you can elect to use FCC part 97 rules instead of part 15 that governs WiFi routers. That means you can use more power and–even more importantly–better antennas to get greater range.

Traditionally, hams have used custom firmware for Netgear routers or Ubiquiti hardware. However, [WZ0W] recently posted his experience using Raspberry Pi boards as mesh nodes. The code (which also works with some other single board computers) is available on GitHub (with details on the project blog). [WZ0W] points out that, unlike using a consumer router, using a Pi provides a reasonably powerful computer for hosting services as well as hosting the network.

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