A Robotic Arm For Those Who Like Their Kinematics Both Ways

October 19, 2018 by Lewin Day 1 Comment

A robotic arm is an excellent idea if you’re looking to get started with electromechanical projects. There’s linkages to design, and motors to drive, but there’s also the matter of control. This is referred to as “kinematics”, and can be considered in both the forward and inverse sense. [aerdronix] built a robotic arm build that works in both ways.

The brains of the build is an Arduino Yun, which receives commands over the USB interface. Control is realised through the Blynk app, which allows IoT projects to easily build apps for smartphones that can be published to the usual platforms.

The arm’s position is controlled in two fashions. When configured to use inverse kinematics, the user commands an end effector position, and the arm figures out the necessary position of the linkages to make it happen. However, the arm can also be used in a forward kinematics mode, where the individual joint positions are commanded, which then determine the end effector’s final position.

Overall, it’s a well-documented build that lays out everything from the basic mechanical design to the software and source code required to control the system. It’s an excellent learning resource for the newcomer, and such an arm could readily be used in more complex projects.

We see plenty of robotic arms around these parts, like this fantastic build based on an IKEA lamp. If you’ve got one, be sure to hit up the tip line. Video after the break.

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Decorative Light Box Lets You Guess The Time

October 19, 2018 by Sven Gregori 7 Comments

Telling time by using the current position of the sun is nothing revolutionary — though it probably was quite the “life hack” back in ancient times, we can assume. On the other hand, showing time by using the current position of the sun is what inspired [Rich Nelson] to create the Day Cycle Clock, a color changing light box of the Philadelphia skyline, simulating a full day and night cycle in real time — servo-controlled sun and moon included.

At its core, the clock uses an Arduino with a real-time clock module, and the TimeLord library to determine the sunrise and sunset times, as well as the current moon phase, based on a given location. The sun and moon are displayed on a 1.44″ LCD which doubles as actual digital clock in case you need a more accurate time telling after all. [Rich] generally went out of his way with planning and attention to detail in this project, as you can see in the linked video, resulting in an impressively clean build surely worthy as gift to his brother. And if you want to build one for yourself, both the Arduino source code and all the mechanical parts are available on GitHub.

An interesting next iteration could be adding internet connectivity to get the current weather situation mixed into the light behavior — not that it would be the first time we’d see weather represented by light. And of course, simulating the northern lights is also always an option.

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Redeem Your Irresponsible 90s Self

October 18, 2018 by Bryan Cockfield 5 Comments

If you were a youth in the 90s, odds are good that you were a part of the virtual pet fad and had your very own beeping Tamagotchi to take care of, much to the chagrin of your parents. Without the appropriate amout of attention each day, the pets could become sick or die, and the only way to prevent this was to sneak the toy into class and hope it didn’t make too much noise. A more responsible solution to this problem would have been to build something to take care of your virtual pet for you.

An art installation in Moscow is using an Arduino to take care of five Tamagotchis simultaneously in a virtal farm of sorts. The system is directly wired to all five toys to simulate button presses, and behaves ideally to make sure all the digital animals are properly cared for. Although no source code is provided, it seems to have some sort of machine learning capability in order to best care for all five pets at the same time. The system also prints out the statuses on a thermal printer, so you can check up on the history of all of the animals.

The popularity of these toys leads to a lot of in-depth investigation of what really goes on inside them, and a lot of other modifications to the original units and to the software. You can get a complete ROM dump of one, build a giant one, or even take care of an infinite number of them. Who would have thought a passing fad would have so much hackability?

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Popup Notification Dinosaur

October 18, 2018 by Bryan Cockfield 1 Comment

There’s a lot going on our virtual spaces, and anyone with a smart phone can attest to this fact. There are pop-up notifications for everything you can imagine, and sometimes it’s possible for the one really important notification to get lost in a sea of minutiae. To really make sure you don’t miss that one important notification, you can offload that task to your own personal dinosaur.

The 3D-printed dinosaur has a rack-and-pinion gear set that allows it to extend upwards when commanded. It also has a set of LEDs for eyes that turn on when it pops up. The two servos and LEDs are controlled by a small Arduino in the base of the dinosaur. This Arduino can be programmed to activate the dinosaur whenver you like, for an email from a specific person, a reply to a comment on Reddit, or an incoming phone call to name a few examples. Be sure to check out the video below the break.

With this dinosaur on your desk, it’s not likely you’ll miss its activation. If you’d like something that has the same function but with less movement and more lights, there’s also a notification 3D cube made out of LEDs that’s sure to catch your eye as well. Continue reading “Popup Notification Dinosaur” →

Flamethrower Gets Update, Retains Some Sketchiness

October 17, 2018 by Bryan Cockfield 16 Comments

Part of what makes flamethrowers fun is their inherent danger. This is what makes a lot of things fun, though, from snowboarding to skydiving to motorcycle riding. As with all of these sensible hobbies, though, it’s important to take as much unnecessary risk out of the activity as possible to make sure you’re around as long as possible to enjoy your chosen activity. With that in mind, [Stephen] decided to make some improvements on his classic wrist-mounted flamethrower.

To start, he ditched the heavy lead-acid battery that powered the contraption in favor of a smaller 5 V battery. In fact, the entire build is much more compact and efficient. He was also able to use the same battery to run a tiny taser that acts as an ignition source for the flamethrower’s fuel. The fuel itself is butane, and the modified flamethrower is able to launch flames much further than the original due to improvements in the fuel delivery system. These improvements also include “Finding a way to prevent butane droplets from lighting and landing on [his] hand” which seems like a necessary feature as well.

The entire build now is very well refined and professional-looking, which is also a major improvement from the first version. It’s also worth watching the video after the break as well, which includes a minor run-in with the New York City fire marshal. And, it still retains some of the danger and all of the fun of the original builds which is something we always like to see.

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DIY Wire Bender Gets Wires All Bent Into Shape

October 14, 2018 by Steven Dufresne 30 Comments

It’s been a while since we’ve shown a DIY wire bending machine, and [How To Mechatronics] has come up with an elegant design with easy construction through the use of 3D-printed parts which handle most of the inherent complexity. This one also has a Z-axis so that you can produce 3D wire shapes. And as with all wire bending machines, it’s fun to watch it in action, which you can do in the video below along with seeing the step-by-step construction.

One nice feature is that he’s included a limit switch for automatically positioning the Z-axis when you first turn it on. It also uses a single 12 volt supply for all the motors, and the Arduino that acts as the brains. The 5 volts for the one servo motor is converted from 12 using an LM7805 voltage regulator. He’s also done a nice job packaging the Arduino, stepper motor driver boards, and the discrete components all onto a single custom surface mount PCB.

The bender isn’t without some issues though, such as that there’s no automatic method for giving it bending instructions. You can write code for the steps into an Arduino sketch, which is really just a lot of copy and paste, and he’s also provided a manual mode. In manual mode, you give it simple commands from a serial terminal. However, it would be only one step more to get those same commands from a file, or perhaps even convert from G-code or some other format.

Another issue is that the wire straightener puts too much tension on the wire, preventing the feeder from being able to pull the wire along. One solution is to feed it pre-straightened wire, not too much to ask for since it’s really the bending we’re after. But fixing this problem outright could be as simple as changing two parts. For the feeder, the wire is pulled between copper pipe and a flat steel bearing, and we can’t help wondering whether perhaps replacing them with a knurled cylinder and a grooved one would work as the people at [PENSA] did with their DIWire which we wrote about back in 2012. Sadly, the blog entries we linked to no longer work but a search shows that their instructable is still up if you want to check out their feeder parts.

As for the applications, we can think of sculpting, fractal antennas, tracks for marble machines, and really anything which could use a wireframe for its structure. Ideas anyone?

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Flash: Arduino Vidor FPGA Instructions Hit France

October 14, 2018 by Al Williams 12 Comments

If you speak French and you have an Arduino Vidor 4000, you are in luck because there’s some good news. The good news is there’s finally some inside information about how to configure the onboard FPGA yourself. The bad news though is that it is pretty sparse. If your high school French isn’t up to the task, there’s always Google Translate.

We knew some of this already. You’ll need Quartus, the FPGA design tool from Altera — er, Intel — and we know about the sample project on GitHub, too. Instead of using conventional Verilog or VHDL, the new information uses schematic capture, but that’s OK. All the design entry winds up in the same place, so it should be easy to adapt to the language of your choice. In fact, in part 2 they show both some schematics and some Verilog. Google Translate does have a little trouble with code comments, though. If you want something even stouter, there’s an example that uses Verilog to output a video frame.

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