Insert Coin (Cell) To Play LedCade

May 6, 2019 by Roger Cheng 3 Comments

In this era of 4K UHD game console graphics and controllers packed full of buttons, triggers, and joysticks, it’s good to occasionally take a step back from the leading edge. Take a breath and remind ourselves that we don’t always need all those pixels and buttons to have some fun. The LedCade is a μ (micro) arcade game cabinet built by [bobricius] for just this kind of minimalist gaming.

Using just three buttons for input and an 8×8 LED matrix for output, the LedCade can nevertheless play ten different games representing classic genres of retro arcade gaming. And in a brilliant implementation of classic hardware hacking humor, a player starts their game by inserting not a monetary coin but a CR2032 coin cell battery.

Behind the screen is a piezo speaker for appropriately vintage game sounds, and an ATmega328 with Arduino code orchestrating the fun. [bobricius] is well practiced at integrating all of these components as a result of developing an earlier project, the single board game console. This time around, the printed circuit board goes beyond being the backbone, the PCB sheet is broken apart and reformed as the enclosure. With classic arcade cabinet proportions, at a far smaller scale.

If single player minimalist gaming isn’t your thing, check out this head-to-head gaming action on 8×8 LED arrays. Or if you prefer your minimalist gaming hardware to be paper-thin, put all the parts on a flexible circuit as the Arduflexboy does.

New Part Day: Lynxmotion Smart Servos

May 3, 2019 by Roger Cheng 33 Comments

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.

Give Your Solar Garden Lights A Color Changing LED Upgrade

April 24, 2019 by Roger Cheng 14 Comments

White LEDs were the technological breakthrough that changed the world of lighting, now they are everywhere. There’s no better sign of their cost-effective ubiquity than the dollar store solar garden light: a complete unit integrating a white LED with its solar cell and battery storage. Not content with boring white lights on the ground, [Emily] decided to switch up their colors with a mix of single-color LEDs and dynamic color-changing LEDs, then hung them up high as colorful solar ornaments.

The heart of these solar devices is a YX8018 chip (or one of its competitors.) While the sun is shining, solar power is directed to charge up the battery. Once the solar cell stops producing power, presumably because the sun has gone down, the chip starts acting as a boost converter (“Joule thief”) pushing a single cell battery voltage up high enough to drive its white LED. Changing that LED over to a single color LED is pretty straightforward, but a color changing LED adds a bit of challenge. The boost converter deliver power in pulses that are too fast for human eyes to pick up but the time between power pulses is long enough to cause a color-changing circuit to reset itself and never get beyond its boot-up color.

The hack to keep a color-changing LED’s cycle going is to add a capacitor to retain some charge between pulses, and a diode to prevent that charge from draining back into the rest of the circuit. A ping-pong ball serves as light diffuser, and the whole thing is hung up using a 3D-printed sheath which adds its own splash of color.

Solar garden lights are great basis for a cheap and easy introduction to electronics hacking. We’ve seen them turn into LED throwies, into a usable flashlight, or even to power an ATTiny microcontroller.

Continue reading “Give Your Solar Garden Lights A Color Changing LED Upgrade” →

Ikea Furniture Hacks Make Accessibility More Accessible

March 31, 2019 by Roger Cheng 11 Comments

The ThisAbles project is a series of 3D-printed IKEA furniture hacks making life easier for those without full use of their bodies. Since IKEA furniture is affordable and available across most of the planet, it’s the ideal target for a project that aims to make 3D-printed improvements accessible to everyone.

These hacks fit all meanings of the word “accessible”: Available worldwide, affordable, and helping people overcome physical barriers of everyday living. ThisAbles has support of multiple organizations including IKEA Israel. In their short introductory video (embedded below the break) they explained their process to find ways to make big impacts with simple 3D-printed modifications. From bumpers protecting furniture against wheelchair damage, to handles that allow drawers to be opened without fine fingertip control. Each of these designs also fit the well-known IKEA aesthetic, including their IKEA style illustrated manuals.

The site launched with thirteen downloadable solutions, but they have ambitions for more with user feedback. There’s a form where people can submit problems they would like to see solved, or alternatively, people can submit solutions they’ve already created and wish to share with the world. Making small changes to commodity IKEA furniture, these 3D printed accessories will have far more impact on people’s lives than the average figurine trinket on Thingiverse. It’s just the latest way we can apply hacker ingenuity to help others to do everything from simple daily tasks to video gaming.

[via Washington Post]

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Printed Perching Pals Proliferate

March 30, 2019 by Roger Cheng 4 Comments

Anansi in African folktale is a trickster and god of stories, usually taking physical form of a spider. Anansi’s adventures through oral tradition have adapted to the situation of people telling those stories, everything ranging from unseasonable weather to living a life in slavery. How might Anansi adapt to the twenty-first century? [odd_jayy] imagined the form of a cyborg spider, and created Asi the robot companion to perch on his shoulder. Anyone who desire their own are invited to visit Asi’s project page.

Asi was inspired by [Alex Glow]’s Archimedes, who also has a project page for anyone to build their own. According to [Alex] at Superconference 2018, she knew of several who have done so, some with their own individual customization. [odd_jayy] loved the idea of a robot companion perched on his shoulder but decided to draw from a different pool of cultural folklore for Asi. Accompanying him to various events like Sparklecon 2019, Asi is always a crowd pleaser wherever they go.

Like every project ever undertaken, there is no shortage of ideas for Asi’s future and [odd_jayy] listed some of them in an interview with [Alex]. (Video after the break.) Adding sound localization components will let Asi face whoever’s speaking nearby. Mechanical articulation for legs would allow more dynamic behaviors while perched, but if the motors are powerful enough, Asi can walk on a surface when not perched. It’s always great to see open source projects inspire even more projects, and watch them as they all evolve in skill and capability. If they all become independently mobile, we’ll need clarification when discussing the average velocity of an unladen folklore robot companion: African or European folklore?

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New Part Day: Pyboard D Is Smaller, Wireless, And Has Expansion Modules

March 20, 2019 by Roger Cheng 16 Comments

Historically, microcontrollers’ limited computing power and storage space meant software had to be written in low-level languages out of necessity. In recent years small affordable chips grew powerful enough that they could theoretically run higher level languages, sparking numerous efforts to turn that theory into reality. MicroPython delivered on this promise in a big way when their Kickstarter-funded pyboard was delivered along with its open source software. Several years have since passed, and now it is time for an upgraded pyboard: the D-series.

We’ve talked with [Damien George] back when the original Kickstarter was still underway. Since the launch of pyboard and release of MicroPython source code, we’ve played with ports running on an ESP8266 and on a BBC micro:bit. The software ecosystem has continued to grow, most recently we looked at LittlevGL graphics library. But just because all the flashy action has been happening on the software side doesn’t mean the hardware side has been sitting stagnant.

Pyboard-D upgraded from original pyboard’s STM32F4 to more capable STM32F7 chips. Witnessing the popularity of MicroPython on networked darlings ESP8266 and ESP32, there will be a pyboard D variant with a Murata 1DX on board for WiFi and Bluetooth connectivity. The new pyboard will be extremely compact with limited edge connections so a fine-pitched connector is required to bring out all the pins. To bring the new pyboard back to its educational and tinkerer roots, a breakout board will take those pins and spread them out in a breadboard friendly form factor. These breakout boards can also host small (12 mm x 12 mm) “tiles” to add individual features.

The wireless pyboard D will obviously invite comparison tests with an ESP32 running MicroPython, and its hardware expansion tiles invites comparison with Adafruit’s Wings. It’ll be interesting to see how they fare once widely available and we can get our hands on them. If you’ve picked up an earlier release at FOSDEM 2019, we invite you to share your experience in comments.

[via Adafruit blog]

Octavo Systems Shows Off With Deadbug Linux Computer

March 15, 2019 by Roger Cheng 11 Comments

Once upon a time, small Linux-capable single board computers were novelties, but not anymore. Today we have a wide selection of them, many built around modules we could buy for our own projects. Some of the chipset suppliers behind these boards compete on cost, others find a niche to differentiate their product. Octavo Systems is one of the latter offering system-in-package (SiP) modules that are specifically designed for easy integration. They described how simple it would be to build a minimal computer using their SC335x C-SiP, and to drive the point home they brought a deadbug implementation to Embedded World 2019. [Short video after the break.]

Most of us encounter Octavo modules as the heart of a BeagleBoard. Their increasing integration made tiny wonders like PocketBeagle possible. But bringing out all those pins for use still required a four-layer circuit board. Octavo’s pitch for hardware professionals center around how easy integration saves time for faster time to market, and fortunately for us easy integration also translates to a more accessible device for our projects. It’s one thing to publish a document describing a hypothetical single-layer PCB for an Octavo module, it’s quite something else to show that concept in action with no PCB at all.

Of course, this little machine only has access to a fraction of the module’s functionality, and it is certainly overkill if the objective is just to blink a few LEDs. If so, we’d just use 555 timers! But it does show how simple a bare bones “Hello World” machine can be built, removing intimidation factor and invite more people to come play.

One of the three top winners in our circuit sculpture contest was a wireframe Z80 computer. There’s quite a jump from a Z80 to an Octavo SC335x, but we’ve already seen one effort by [Zach] over Supercon 2018 weekend to build a deadbug computer with an Octavo module. It won’t be long before someone one-ups this minimalist LED blinker with something more sophisticated and we can’t wait to see it. Continue reading “Octavo Systems Shows Off With Deadbug Linux Computer” →