An Arduino Powered Tank Built To Pull Planes

June 19, 2018 by 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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Tables Are Turned As Robots Assemble IKEA Furniture

June 19, 2018 by 15 Comments

Hackaday pages are rife with examples of robots being built with furniture parts. In this example, the tables are turned and robots are the masters of IKEA pieces. We are not silly enough to assume that these robots unfolded the instructions, looked at one another, scratched their CPUs, and began assembling. Of course, the procedure was preordained by the programmers, but the way they mate the pegs into the ends of the cross-members is a very human thing to do. It reminds us of finding a phone charging socket in the dark. This kind of behavior is due to force feedback which tell the robots when a piece is properly seated which means that they can use vision to fit the components together without sub-millimeter precision.

All the hardware used to make the IKEA assembler is publicly available, and while it may be out of the typical hacker price range, this is a sign of the times as robots become part of the household. Currently, the household robots are washing machines, smart speakers, and 3D printers. Ten years ago those weren’t Internet connected machines so it should be no surprise if robotic arms join the club of household robots soon. Your next robotics project could be the tipping point that brings a new class of robots to the home.

Back to our usual hijinks, here is a robot arm from IKEA parts and a projector built into a similar lamp. or a 3D printer enclosed in an IKEA cabinet for a classy home robot.

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Hybrid Lab Power Supply From Broken Audio Amp

June 18, 2018 by 9 Comments

The lab power supply is an essential part of any respectable electronics workbench. However, the cost of buying a unit that has all the features required can be eye-wateringly high for such a seemingly simple device. [The Post Apocalyptic Inventor] has showed us how to build a quality bench power supply from the guts of an old audio amplifier.

We’ve covered our fair share of DIY power supplies here at Hackaday, and despite this one being a year old, it goes the extra mile for a number of reasons. Firstly, many of the expensive and key components are salvaged from a faulty audio amp: the transformer, large heatsink and chassis, as well as miscellaneous capacitors, pots, power resistors and relays. Secondly, this power supply is a hybrid. As well as two outputs from off-the-shelf buck and boost converters, there is also a linear supply. The efficiency of the switching supplies is great for general purpose work, but having a low-ripple linear output on tap for testing RF and audio projects is really handy.

The addition of the linear regulator is covered in a second video, and it’s impressively technically comprehensive. [TPAI] does a great job of explaining the function of all the parts which comprise his linear supply, and builds it up manually from discrete components. To monitor the voltage and current on the front panel, two vintage dial voltmeters are used, after one is converted to an ammeter. It’s these small auxiliary hacks which make this project stand out – another example is the rewiring of the transformer secondary and bridge rectifier to obtain a 38V rail rated for twice the original current.

The Chinese DC-DC switching converters at the heart of this build are pretty popular these days, in fact we’re even seeing open source firmware being developed for them. If you want to find out more about how they operate on a basic level, here’s how a buck converter works, and also the science behind boost converters.

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The Colpitts Oscillator Explained

June 18, 2018 by 10 Comments

The Colpitts oscillator is a time-tested design — from 1918. [The Offset Volt] has a few videos covering the design of these circuits including an op-amp and a transistor version. You can find the videos below.

You can tell a Colpitts oscillator by the two capacitors in the feedback circuit. The capacitors form an effective capacitance for the circuit (assuming you have C1 and C2) of the product of C1 and C2 divided by the sum of the two capacitors. The effective capacitance and the inductance form a bandpass filter that is very sharp at the frequency of interest, allowing the amplifier to build up oscillations at that frequency.

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Raytheon’s Analog Read-Only Memory Is Tube-Based

June 18, 2018 by 8 Comments

There are many ways of storing data in a computer’s memory, and not all of them allow the computer to write to it. For older equipment, this was often a physical limitation to the hardware itself. It’s easier and cheaper for some memory to be read-only, but if you go back really far you reach a time before even ROMs were widespread. One fascinating memory scheme is this example using a vacuum tube that stores the characters needed for a display.

[eric] over at TubeTime recently came across a Raytheon monoscope from days of yore and started figuring out how it works. The device is essentially a character display in an oscilloscope-like CRT package, but the way that it displays the characters is an interesting walk through history. The monoscope has two circuits, one which selects the character and the other determines the position on the screen. Each circuit is fed a delightfully analog sine wave, which allows the device to create essentially a scanning pattern on the screen for refreshing the display.

[eric] goes into a lot of detail on how this c.1967 device works, and it’s interesting to see how engineers were able to get working memory with their relatively limited toolset. One of the nice things about working in the analog world, though, is that it’s relatively easy to figure out how things work and start using them for all kinds of other purposes, like old analog UHF TV tuners.

Arduino Watchdog Sniffs Out Hot 3D Printers

June 18, 2018 by 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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Buttery Smooth Fades With The Power Of HSV

June 18, 2018 by 20 Comments

In firmware-land we usually refer to colors using RGB. This is intuitively pleasing with a little background on color theory and an understanding of how multicolor LEDs work. Most of the colorful LEDs we are use not actually a single diode. They are red, green, and blue diodes shoved together in tight quarters. (Though interestingly very high end LEDs use even more colors than that, but that’s a topic for another article.) When all three light up at once the emitted light munges together into a single color which your brain perceives. Appropriately the schematic symbol for an RGB LED without an onboard controller typically depicts three discrete LEDs all together. So it’s clear why representing an RGB LED in code as three individual values {R, G, B} makes sense. But binding our representation of color in firmware to the physical system we accidentally limit ourselves.

The inside of an RGB LED

Last time we talked about color spaces, we learned about different ways to represent color spatially. The key insight was that these models called color spaces could be used to represent the same colors using different groups of values. And in fact that the grouped values themselves could be used to describe multidimensional spacial coordinates. But that post was missing the punchline. “So what if you can represent colors in a cylinder!” I hear you cry. “Why do I care?” Well, it turns out that using colorspace can make some common firmware tasks easier. Follow on to learn how!

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