Blinging Up A Scope: Scale Your Divisions In Style

June 14, 2018 by Ben James 20 Comments

When a hacker owns an oscilloscope, it’s more than a possession. Weary nights are spent staring at the display, frantically twiddling the dials to coax out vital information. Over time, a bond is formed – and only the best will do for your scope. So why settle for the stock plastic dials when you could go for gold? Well in case you hadn’t noticed, we’re partial to a bit of over-engineering here at Hackaday, and [AvE] has upgraded his Rigol scope by adding metal knobs.

Employing his usual talent in the shop, [AvE] first turns the basic knob shapes from the stock, before drilling them and milling the outer texture pattern at an angle. Voilà: six custom knobs for 100% more torque and traction control. No matter how trivial the project, it’s always good to watch him at work. This [AvE] video doesn’t come with the usual fruity language warning; instead this build is set to the swelling tones of Beethoven. “Less Talk – More Action!” says the title, but we have to say that we miss his quips. That said, he still manages to deliver his signature humour through action alone.

For some slightly more functional oscilloscope upgrades, you can read about adding a hybrid touchscreen interface, or hacking a Rigol scope’s software to unlock greater bandwidth, storage depth and more.

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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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Making Robot Snakes That Slither, Sidewind, And Strike

June 14, 2018 by Steven Dufresne 5 Comments

[Will Donaldson] has been making robot snakes of all sorts. One of his snakes hugs the ground, slithering across it with a sine wave motion. Flipping it on its side and calling different code, that same snake also moves like an inchworm. Another of his snakes lifts parts of itself upward to move sideways across the ground, again using sine waves.

At first, his slithering snake would only oscillate in place on the floor. Looking more closely at biological snakes, he found that part of the reason they moved forward was due to their scales. The scales move smoothly over the ground in one direction but grip when pushed backward or sideways. He also found work done at Harvard University where they combined pumped air and papercraft to make scales which change shape. And so [Will] designed and 3D printed some scales for his snake. However, as you can see in the video below, they didn’t work on carpet.

His success came when he added wheels to each segment. They didn’t work like a car, there was no engine turning the wheels. Instead, they acted more like scales, rotating freely in one direction and gripping when pushed sideways. This success also allowed him to add a parameter to his code for turning left or right.

As we said above, he can flip the ground hugger sideways and run it as an inchworm and he also has a working sidewinder snake variation. The sidewinder can even lift up its head and strike like a cobra. Check out his hackaday.io page if you want to make your own. He’s provided STL files, code, and construction details.

[Will] has a lot of future plans for his snakes. Currently, they’re tethered to a modified ATX power supply but he’d like to incorporate LiPo batteries into the snakes instead. His original goal was to make a tree climbing snake like the one by the Biorobotics lab at Carnegie Mellon University (updated link for the article) but his first snake wasn’t long enough. He still plans on pursuing that as well as an underwater electronic eel. There seems to be no limit to the things he can try. For now, check out the video below to see his successes and his failures so far. Maybe you even have some suggestions for those tricky scales. The undersides of his snake’s segments do seem modular, lending themselves to experimentation.

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Espresso Machine From Motorbike Engine Parts

June 14, 2018 by Steven Dufresne 15 Comments

[Rulof Maker] is a master at making things from salvaged parts, and being an Italian lover of espresso coffee, this time he’s made an espresso machine. The parts in question are a piston and cylinder from an old motorbike, believe it or not, and parts from an IKEA lamp.

Why the piston and cylinder? For those not familiar with espresso machines, they work by forcing pressurized, almost boiling water through ground coffee. He therefore puts the water in the piston cylinder, and levers the piston down onto it, forcing the water out the bottom of the cylinder and through the waiting coffee grounds. Parts from the IKEA lamp form a base for the waiting cup to sit on.

Of course, he takes great care to clean out any burnt oil and gas before starting. We also like how he centers a lever arm on a U-shaped bolt using two springs. Clever. But see the master in action for yourself in the video below.

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Folding Robots With Special Materials

June 14, 2018 by Brian Benchoff 16 Comments

When it comes to robots, we usually see some aluminum extrusion, laser-cut parts, maybe some 3D printed parts, and possibly a few Erector sets confabulated into a robot arm. This entry for the Hackaday Prize is anything but. It’s a robot chassis, a 3D printer, and the structural frame for any sort of moving project that’s made out of a special composite material.

[Marc]’s project for the Hackaday Prize is all about articulated mechanisms. Instead of the usual structural components, he’s using Hylite, a special material that’s basically a polypropylene core clad in a sheet of aluminum on both sides. By carefully milling away the aluminum on both sides, [Marc] is creating a living hinge that can be used to build a 3D printer, robot, or really anything else.

This really isn’t a finished project; it’s more of a technology demonstrator. That said, [Marc] has a lot of examples where he can bend these Hylite aluminum plates over on themselves, can create boxes and space frames, and has the ability to create just about any shape he wants. It’s really a highly precise means of bending aluminum with a mill, and has the added benefit of looking really, really good.

Already, [Marc] has a few interesting robots that are built around this construction technology. The first is a remote control focus for a telescope that simply connects an eyepiece to the scope. Actuation is provided pneumatically, and all reports say this example works well. The other example is a flat-pack phone stand. It’s a bit simpler than a focus mechanism, but it is a small and inexpensive way to show off the technology. Great work, and an excellent project in The Hackaday Prize.

General Purpose I/O: How To Get More

June 14, 2018 by Inderpreet Singh 28 Comments

The first program anyone writes for a microcontroller is the blinking LED which involves toggling a general-purpose input/output (GPIO) on and off. Consequently, the same GPIO can be used to read digital bits as well. A traditional microcontroller like the 8051 is available in DIP packages ranging from 20 pins to 40 pins. Some trade the number of GPIOs for compactness while other devices offer a larger number of GPIOs at the cost of complexity in fitting the part into your design. In this article, we take a quick look at applications that require a larger number of GPIOs and traditional solutions for the problem.

A GPIO is a generic pin on an integrated circuit or computer board whose behavior, including whether it is an input or output pin, is controllable by the user at runtime. See the internal diagram of the GPIO circuit for the ATmega328 for reference.

Simply put, each GPIO has a latch connected to a drive circuit with transistors for the output part and another latch for the input part. In the case of the ATmega328, there is a direction register as well, whereas, in the case of the 8051, the output register serves as the direction register where writing a 1 to it sets it in output mode.

The important thing to note here is that since all the circuits are on the same piece of silicon, the operations are relatively fast. Having all the latches and registers on the same bus means it takes just one instruction to write or read a byte from any GPIO register.
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DIY Talkbox Gives You More Bounce To The Ounce

June 14, 2018 by Kristina Panos 10 Comments

Back in the 70s, you couldn’t swing a macrame plant hanger around a record store without knocking over numerous displays of albums featuring talkboxes. They were all over 70s music, kind of like how almost every 80s song has a sax solo and/or Michael McDonald on backing vocals. Not sure you’ve heard one being used? Trust us, you definitely have and just don’t realize it.

Talkboxes are essentially an amplifier and a speaker contained in a box. The speaker is the acoustic diaphragm type used in bullhorns and civil defense sirens. You run your guitar, keyboard, or electrified hurdy gurdy into the box, and instead of driving a horn, the sound travels up a clear plastic tube and into your mouth. Your mouth, fine resonant cavity that it is, becomes the final effect pedal. Any way you can manipulate it will shape the sound coming from the instrument. Flap those lips, and suddenly you’re talking like a robot. Who wouldn’t want one of these?

So they aren’t complicated, but you wouldn’t know it from the price of commercial ones. [mosivers] really digs the sound and wanted to build one, so he scoured the internet to figure out how to do so properly and shared his findings in this Instructable. The most important bit is the compression driver. The drivers that featured in the original talkboxes aren’t made anymore, but there are suitable replacements for ~$40.

The next most important part is a high-pass filter to keep really low frequencies from damaging the driver. After that it’s down to the amplifier, some passives, and the all-important tube. You could laser cut an enclosure as [mosivers] did, or be the first person in history to reuse a Danish butter cookie tin for something other than sewing supplies. Boogie on down past the break and let’s groove tonight.

Speaking of the 80s, here’s a DIY talkbox built on a Game Boy.

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