Remote Control Robot Deals Dominoes

Oh, dominoes — the fun of knocking them down is inversely proportional to the pain of setting them all up again. [DIY Machines] is saving loads of time by automating the boring part with a remote control domino-laying machine. If only it could pick them back up.

This machine can be driven directly over Bluetooth like an R/C car, or programmed to follow a predetermined path via Arduino code. Here’s how it works: an Arduino Uno drives two servos and one motor. The 1:90 geared motor drives the robot around using a 180° servo to steer. A continuous servo turns the carousel, which holds nearly 140 dominoes. We love that the carousel is designed to be hot-swappable, so you can keep a spare ready to go.

[DIY Machines] really thought of everything. Every dozen or so dominoes, the machine leaves a gap in case one of the dominoes is tipped prematurely. There are also a couple of accessories for it, like a speedy domino loading stick and a fun little staircase bridge to add to your domino creations. Though all the machine files are freely available, [DIY Machines] requests a small donation for the accessories files. Check out the complete build video after the break, followed by a bonus video that focuses on upgrading the machine with an HM10 Bluetooth module for controlling it directly with a phone.

This certainly isn’t the first domino-laying device we’ve seen, though it might be the most accessorized. [Matthias Wandel]’s version uses only one motor to move and deal the dominoes.

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Dice Roller Keeps Germs Out Of Your Snake Eyes

Do you need a to find a more sanitary way to roll the dice at your next socially-distanced board game gathering? [CJA3D]’s pop-o-matic mason jar dice roller can roll the bones two different ways — either by hitting that big, inviting arcade button, or though a web app that everyone can access on their own phones.

We think this looks great, and is a great reuse of a glass jar. The brains of this operation is an ESP8266, which drives a continuous-rotation servo underneath the dice. Push the button or use the web app and the servo disturbs the plate, moving the dice around.

Besides the sanitary aspect, one benefit of using the web app is that there are four different speed presets for the servo. As a bonus, [CJA3D] included the files for a pair of printed 6-sided dice. Click through to the project to see it in action.

We know you take games seriously, and so do we. Just look at this dice roller that uses machine vision to ensure fairness.

ExoMy Is A Miniature European Mars Rover With A Friendly Face

Over the past few weeks, a new season of Mars fever kicked off with launches of three interplanetary missions. And since there’s a sizable overlap between fans of spaceflight and those of electronics and 3D printing, the European Space Agency released the ExoMy rover for those who want to experience a little bit of Mars from home.

ExoMy’s smiling face and cartoonish proportions are an adaptation of ESA’s Rosalind Franklin (formerly the ExoMars) rover which, if 2020 hadn’t turned out to be 2020, would have been on its way to Mars as well. While Rosalind Franklin must wait for the next Mars launch window, we can launch ExoMy missions to our homes now. Like the real ESA rover, ExoMy has a triple bogie suspension design distinctly different from the rocker-bogie design used by NASA JPL’s rover family. Steering all six wheels rather than just four, ExoMy has maneuvering chops visible in a short Instagram video clip (also embedded after the break).

ExoMy’s quoted price of admission is in the range of 250-500€. Perusing instructions posted on GitHub, we see an electronics nervous system built around a Raspberry Pi. Its published software stack is configured for human remote control, but as it is already running ROS (Robot Operating System), it should be an easy on-ramp for ExoMars builders with the ambition of adding autonomy.

ExoMy joins the ranks of open source rover designs available to hackers with 3D printing, electronics, and software skills. We recently covered a much larger rover project modeled after Curiosity. Two years ago NASA JPL released an open source rover of their own targeting educators, inspiring this writer’s own Sawppy rover project, which is in turn just one of many projects tagged “Rover” on Hackers love rovers!

New Part Day: Lynxmotion Smart Servos

Anyone who shops for robotics kits would have come across a few designed by Lynxmotion. They’ve been helping people build robots since 1995, from robot arm kits to hexapod chassis and everything in between. We would expect these people know their motors, so when they launched their own line of servo motors called Lynxmotion Smart Servos (LSS), it is worth spending a bit of time to look over what they offer.

While these new devices have a PWM mode compatible with classic remote control servos, unleashing their full power requires bidirectional communication over a serial bus. We’ve previously given an overview of three serial bus servos already on the market for comparison. A quick look at the $68-$100 price tags listed on Lynxmotion’s parent company RobotShop made it clear they do not intend to compete on price, so what interesting features do these new kids on the block have?

Digging into product documentation found some great details. Acceleration and deceleration rates are adjustable, which can help with smoother robot movement. There’s also an adjustable level of “stiffness” that adds some “give” (compliance) so a robot won’t have to be as stiff as… well, a robot!

Mechanically, the most interesting internal component is the magnetic position sensor. They are far more precise than potentiometers, but more importantly, they allow positioning anywhere within full 360 degrees. Many other serial bus servos are constrained to positions within an arc less than 360 degrees leaving a blind spot.

An interesting quirk of the LSS offerings is that the serial communication protocol uses human-readable text characters, so sending a number 255 means transmitting a three byte string ‘2’, ‘5’, and ‘5’ instead of single byte 0xFF. This would make debugging our custom robot code far easier, at the cost of reduced bandwidth efficiency and loss of checksum for detecting communication errors. It’s a trade-off that some robot builders would be happy to make, but others might not.

Externally, these servos have bountiful mounting options including some we didn’t know to ask for. Historically Lynxmotion kits have used a wide variety of servo mounting brackets, so they are motivated to make mechanical integration easy. The most novel offering is the ability to bolt external gears to the servo body. A set of 1:3 gears allow for gearing the servo up or down, or you can use a set of 1:1 gears for a compact gripper.

As you’d expect of servos in this price range, they all have metal gears, but they also have the ability to power the motor directly from a battery pack (a 3 cell lithium polymer is recommended). There are additional features, like an RGB LED for visual feedback, which we didn’t cover here so dig into the documentation for more. We look forward to seeing how these interesting little actuators perform in future robotics projects.

Palm-Sized Gatling Gun Has 32 Mini Elastics With Your Name On Them

One thing 3D printers excel at is being able to easily create objects that would be daunting by other methods, something that also allows for rapid design iteration. That’s apparent in [Canino]’s palm-sized, gatling-style, motorized 32-elastic launcher.

The cannon has a rotary barrel driven by a small motor, and a clever sear design uses the rotation of the barrels like a worm gear. The rotating barrel has a spiral formation of hooks which anchor the stretched elastic bands. A small ramp rides that spiral gap, lifting ends of stretched bands one at a time as the assembly turns. This movement (and therefore the firing control) is done with a small continuous rotation servo. While in theory any motor would do, using a servo has the advantage of being a standardized shape, and therefore easy to integrate into the design. A video is embedded below in which you can see it work, along with some close-ups of the action.

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Dog-Or-Catapult Controls The Speed Of The Feed

[NathanKing] has a cute, rambunctious pupper who eats way too fast for her own good. He’s tried various distribution methods intended to get her to slow down, but she’s just too excited to eat. [Nathan]’s latest solution is to launch the food piece by piece using a catapult. The dog loves the gamified feeding method, which is sort of like one-way fetch. She gets a bit of exercise, and everyone is amused for the half hour it takes to fling 1.5 cups of food one piece at a time.

Electronics-wise, this food flinger doesn’t use much more than three servos and an Arduino Uno. Servo #1 pulls the arm back until it hits a limit switch. Servo #2 holds the arm down , and servo #3 rotates the food tube until it drops a unit of kibble into the spoon. Then servo #2 lets the arm go, and the tasty morsel flies about 30 feet (10 meters).

[Nathan] doesn’t offer step-by-step instructions, but there is more than enough detail to replicate this project. He used what he had on hand, such as scrap aluminium from another project for the frame. Future plans include swapping out the 6V lantern battery for rechargeable AAs, and downsizing to a Nano. We’ve fetched a couple of videos for you and thrown them in after the break. Go get ’em, reader!

Pets need plenty of water, especially during the summer. Here’s a no-sweat automatic watering solution we saw a few years ago.

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Wrangling RC Servos Becoming A Hassle? Try Serial Bus Servos!

When we need actuators for a project, a servo from the remote-control hobby world is a popular solution. Though as the number of servos go up, keeping their wires neat and managing their control signals become a challenge. Once we start running more servos than we have fingers and toes, it’s worth considering the serial bus variety. Today we’ll go over what they are and examine three products on the market.

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