An Arduino Powered Tank Built To Pull Planes

June 19, 2018 by Tom Nardi 39 Comments

Surely our readers are well aware of all the downsides of owning an airplane. Certainly the cost of fuel is a big one. Birds are a problem, probably. That bill from the traveling propeller sharpener is a killer too…right? Alright fine, we admit it, nobody here at Hackaday owns an airplane. But probably neither do most of you; so don’t look so smug, pal.

But if you did own a plane, or at least work at a small airport, you’d know that moving the things around on the ground is kind of a hassle. Smaller planes can be pulled by hand, but once they get up to a certain size you’ll want some kind of vehicle to help out. [Anthony DiPilato] wanted a way to move around a roughly 5,200 pound Cessna 310, and decided that all the commercial options were too expensive. So he built his own Arduino powered tank to muscle the airplane around the tarmac (if site is down try Google cache), and his journey from idea to finished product is absolutely fascinating to see.

So the idea here is pretty simple. A little metal cart equipped with two beefy motors, an Arduino Mega, a pair of motor controllers, and a HC-08 Bluetooth module so you can control it from your phone. How hard could it be, right? Well, it turns out combining all those raw components into a little machine that’s strong enough to tow a full-scale aircraft takes some trial and error.

It took [Anthony] five iterations before he fine tuned the design to the point it was able to successfully drag the Cessna without crippling under the pressure. The early versions featured wheels, but eventually it was decided that a tracked vehicle would be required to get enough grip on the blacktop. Luckily for us, each failed design is shown along with a brief explanation about what went wrong. Admittedly it’s unlikely any of us will be recreating this particular project, but we always love to see when somebody goes through the trouble of explaining what went wrong. When you include that kind of information, somewhere, somehow, you’re saving another maker a bit of time and aggravation.

Hackers absolutely love machines with tank treads. From massive 3D printed designs to vaguely disturbing humanoid robots, there’s perhaps no sweeter form of locomotion in the hacker arsenal.

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Arduino Watchdog Sniffs Out Hot 3D Printers

June 18, 2018 by Tom Nardi 23 Comments

We know we’ve told you this already, but you should really keep a close eye on your 3D printer. The cheaper import machines are starting to display a worrying tendency to go up in flames, either due to cheap components or design flaws. The fact that it happens is, sadly, no longer up for debate. The best thing we can do now is figure out ways to mitigate the risk for all the printers that are already deployed in the field.

At the risk of making a generalization, most 3D printer fires seem to be due to overheating components. Not a huge surprise, of course, as parts of a 3D printer heat up to hundreds of degrees and must remain there for hours and hours on end. Accordingly, [Bin Sun] has created a very slick device that keeps a close eye on the printer’s temperature at various locations, and cuts power if anything goes out of acceptable range.

The device is powered by an Arduino Nano and uses a 1602 serial LCD and KY040 rotary encoder to provide the user interface. The user can set the shutdown temperature with the encoder knob, and the 16×2 character LCD will give a real-time display of current temperature and power status.

Once the user-defined temperature is met or exceeded, the device cuts power to the printer with an optocoupler relay. It will also sound an alarm for one minute so anyone in the area will know the printer needs some immediate attention.

We’ve recently covered a similar device that minimizes the amount of time the printer is powered on, but checking temperature and acting on it in real-time seems a better bet. No matter what, we’d still suggest adding a smoke detector and fire extinguisher to your list of essential 3D printer accessories.

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Watch The World Spin With The Earth Clock

June 18, 2018 by Sven Gregori 9 Comments

With the June solstice right around the corner, it’s a perfect time to witness first hand the effects of Earth’s axial tilt on the day’s length above and beyond 60 degrees latitude. But if you can’t make it there, or otherwise prefer a more regular, less deprived sleep pattern, you can always resort to simulations to demonstrate the phenomenon. [SimonRob] for example built a clock with a real time rotating model of Earth to visualize its exposure to the sun over the year.

The daily rotating cycle, as well as Earth’s rotation within one year, are simulated with a hand painted plastic ball attached to a rotating axis and mounted on a rotating plate. The hand painting was done with a neat trick; placing printed slivers of an atlas inside the transparent orb to serve as guides. Movement for both axes are driven by a pair of stepper motors and a ring of LEDs in the same diameter as the Earth model is used to represent the Sun. You can of course wait a whole year to observe it all in real time, or then make use of a set of buttons that lets you fast forward and reverse time.

Earth’s rotation, and especially countering it, is a regular concept in astrophotography, so it’s a nice change of perspective to use it to look onto Earth itself from the outside. And who knows, if [SimonRob] ever feels like extending his clock with an aurora borealis simulation, he might find inspiration in this northern lights tracking light show.

This is a spectacular showpiece and a great project you can do with common tools already in your workshop. Once you’ve mastered earth, put on your machinists hat and give the solar system a try.

3D Printer Tech Cuts Paper

June 16, 2018 by Al Williams 18 Comments

While 3D printing has been a great thing all by itself, it has also made electromechanical hardware a commodity item. Instead of raiding an old printer for motors and rods of unknown provenance, you can now buy everything very inexpensively due to the economy of scale and offshore manufacturing.

[Mr. Innovation] proves this point with his recent paper cutting machine which feeds and slices paper strips with user-selected width and quantity. He did steal one roller assembly from an old printer, but most of it is straight out of a 3D printer build. There’s NEMA stepper motors, modular motor driver boards, smooth rods, belts, and pulleys.

The blade of the cutter is just a standard snap off box cutter blade. It is angled so it doesn’t drag when the motor pulls it back to the home position after a cut. Honestly, we might have made the paper mechanism retract the paper a bit at that point, but that would be simple to add to the device’s firmware.

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A Crash Course In Reliable Communication

June 14, 2018 by Tom Nardi 21 Comments

It’s probably fair to say that anyone reading these words understands conceptually how physically connected devices communicate with each other. In the most basic configuration, one wire establishes a common ground as a shared reference point and then the “signal” is sent over a second wire. But what actually is a signal, how do the devices stay synchronized, and what happens when a dodgy link causes some data to go missing?

All of these questions, and more, are addressed by [Ben Eater] in his fascinating series on data transmission. He takes a very low-level approach to explaining the basics of communication, starting with the concept of non-return-to-zero encoding and working his way to a shared clock signal to make sure all of the devices in the network are in step. Most of us are familiar with the data and clock wires used in serial communications protocols like I2C, but rarely do you get to see such a clear and detailed explanation of how it all works.

He demonstrates the challenge of getting two independent devices to communicate, trying in vain to adjust the delays on the receiving and transmitting Arduinos to try to establish a reliable link at a leisurely five bits per second. But even at this digital snail’s pace, errors pop up within a few seconds. [Ben] goes on to show that the oscillators used in consumer electronics simply aren’t consistent enough between devices to stay synchronized for more than a few hundred bits. Until atomic clocks come standard on the Arduino, it’s just not an option.

[Ben] then explains the concept of a dedicated clock signal, and how it can be used to make sure the devices are in sync even if their local clocks drift around. As he shows, as long as the data signal and the clock signal are hitting at the same time, the actual timing doesn’t matter much. Even within the confines of this basic demo, some drift in the clock signal is observed, but it has no detrimental effect on communication.

In the next part of the series, [Ben] will tackle error correction techniques. Until then, you might want to check out the fantastic piece [Elliot Williams] put together on I2C.

[Thanks to George Graves for the tip.]

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Poetry Is The Fruit Of This Loom

June 14, 2018 by Tom Nardi 14 Comments

We’d wager that most people reading these words have never used a loom before. Nor have most of you churned butter, or ridden in a horse-drawn wagon. Despite these things being state of the art technology at one point, today the average person is only dimly aware of their existence. In the developed world, life has moved on. We don’t make our own clothes or grow our own crops. We consume, but the where and how of production has become nebulous to us.

[David Heisserer] and his wife [Danielle Everine], believe this modern separation between consumption and production is a mistake. How can we appreciate where our clothing comes from, much less the people who make it, without understanding the domestic labor that was once required to produce even a simple garment? In an effort to educate the public on textile production in a fun and meaningful way, they’ve created a poetry printing loom called Meme Weaver.

The Meme Weaver will be cranking out words of woolen wisdom at the Northern Spark Festival taking place June 15th and 16th in downtown Minneapolis. If any Hackaday readers in the area get a chance to check out the machine, we’d love to hear about it in the comments. Take photos! Just don’t blame us if you have a sudden urge to make all of your clothing afterwards.
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Automatic Sunglasses For The Lazy Hacker

June 13, 2018 by Adam Fabio 10 Comments

[Andreas] may have created the ultimate lazy hacker accessory: automatic sunglasses, or “Selfblending sunglasses” as he creatively titled his video. If you can’t tell from the name, these are glasses that you never have to take off. If the light is dim, they move away from your eyes. Going back outside to bright light? The glasses move to protect your eyes.

The glasses consist of a couple of micro servos which move tinted lenses toward or away from the user’s eyes. A side-mounted Arduino Uno reads a CdS cell light sensor and drives the servos. Why an Uno rather than a much more wearable Arduino Nano? It’s what [Andreas] had lying around.

Yes, a good portion of the fun of this build is [Andreas’] comedy. But the best part comes when he tests the glasses out — in an actual car on the highway. The glasses work better than expected — moving the lenses into and out of [Andreas] field of view as he drives through tunnels. You can actually see how surprised [Andreas] is that it works so well.

These aren’t the first automatic sunglasses we’ve seen, nor are they the most peril-sensitive. Still, it’s a fun project and the video gave us a few chuckles.

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