Blackboard Becomes Tidy Pen Plotter

Printers are all well and good, but they’re generally limited to smaller paper sizes and use expensive ink. If you instead want to produce art on a larger scale, a plotter can be a great way to go. [tuenhidiy] built a tidy example using an old blackboard as a base.

These days, such a build is quite easily approachable, thanks to the broad DIY CNC and 3D printing communities. The plotter consists of a pair of stepper motors, driven by an off-the-shelf RAMPS 1.4 controller and an Arduino Mega 2560. The motors are mounted at the top corners of the blackboard, and move the pen holder via a pair of toothed belts, counter-weighted for stability. The pen holder itself mounts a simple permanent marker, and uses a servo to push the holder away from the paper for retraction, rather than moving the pen itself. Control of the system is via the Makelangelo firmware, an open-source effort capable of driving a wide variety of CNC motion systems.

The final result is a simple plotter using readily available parts that can reliably plot large graphics on a piece of A1 paper. We’re particularly impressed by the clean, continuous lines it produces – testament to a sound mechanical design.

We see plenty of plotters around these parts; even rotary types that can draw on curves. Video after the break.

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Domino Layer Lets You Focus On Toppling

Knocking dominoes down is a fun pastime for a rainy afternoon, but setting them all up can be a drag. Thankfully, [Lewis] of [DIY Machines] has built a helpful machine to do the job for you, letting you focus on the fun part instead!

The machine is run by an Arduino Uno, that can be pre-programmed with a layout or controlled over Bluetooth in real time. It uses a geared-down DC motor to drive around a smooth surface, with a servo for steering. A second servo is used to turn a carousel loaded with up to 130 dominoes, allowing the machine to lay long runs without needing a refill. It’s designed to be easy to change so multiple carousels can be printed to quickly run courses of extended lengths.

The build is a great example of a machine capable of doing a tricky task with ease, thanks to 3D printing and smart design. We’re particularly impressed with the simple domino transport mechanism integrated into the drive system without requiring extra motors or servos. It’s not the first domino layer we’ve seen, either. Video after the break.

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Cupcake Machine Makes Tasty, If Weird, Creations

Baking cupcakes is a fun pastime, and one which we imagine many people took up in this year of quarantine and lockdown. However, anything a human can do, a machine can certainly make an attempt at, as [Skyentific] shows with this roboticized cupcake machine.

The build will be familiar to anyone who has worked with 3D printers or DIY CNC machines before. A series of stepper motors move a carriage carrying a regulation-sized patty pan. This is filled with dough from a tube, squirted out by a modified electric caulking gun. The carriage then transports it to a small microwave chamber of custom construction. After a minute or so of cooking, it’s then removed, and topping is applied from a further two caulking guns. An Arduino is in charge of the operation, running the show with some stepper drivers, limit switches, and a bank of relays.

The final product isn’t the prettiest cupcake we’ve ever seen, but it’s perfectly edible. We can imagine with some small modifications the device could probably cook batches of four at a time without too much trouble. We’ve seen other baking robots before, too. Video after the break.

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Water And Molten Aluminium Is A Dangerous Combination

It is not uncommon for a Hackaday writer to trawl the comments section of a given article, looking for insights or to learn something new. Often, those with experience in various fields will share kernels of knowledge or raise questions on a particular topic. Recently, I happened to be glazing over an article on aluminium casting with interest, given my own experience in the field. One comment in particular caught my eye.

 And no, the water won’t cause a steam explosion. There’s a guy on youtube (myfordlover, I think) who disproves that myth with molten iron, pouring the iron into water, pouring water into a ladle of molten iron and so on. We’ll be happy to do a video demonstrating this with aluminum if so desired.

Having worked for some time in an aluminium die casting plant, I sincerely hope [John] did not attempt this feat. While there are a number of YouTube videos showing that this can be done without calamity, there are many showing the exact opposite. Mixing molten aluminium and water often ends very poorly, causing serious injury or even fatalities in the workplace. Let’s dive deeper to see why that is.

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New Part Day: SD NAND Are Surface Mount Chips That Work Like An SD Card

SD cards have long been a favorite with microcontroller hobbyists. Cheap, readily available, and easily interfaced, they remain a staple for small projects that need to store a lot of data. Now, they’re available in chip form! These are known as SD NAND parts that emulate the SD card interface itself.

[LadyAda] recently gave them a test-drive after spotting a tweet from [Greg Davill] (who we’re familiar with thanks to his excellent LED cubes). The devices are manufactured by XTX Technology and available from LCSC in a range of 1, 2, 4, and 8 GB sizes. [Ivan Grokhotkov] also illuminated a similar device from another maker in a reply to [Greg’s] original tweet, so there may be more sources out there.

These chips come in standard LGA8 surface mount package and can be easily soldered to a board, offering mechanical and manufacturing benefits versus using a normal SD or microSD card in a slot-type connector. Also, unlike other SMD flash memory parts, they handle all the file system details and wear levelling for you! With the inflation of SD card sizes, it’s also difficult to find these on the shelf in normal cards these days.

[Adafruit] plan to have a breakout for these parts out soon with a level shifter included for ease of use. We can imagine these chips finding their way into all manner of datalogger projects, since they can be ordered with other parts and permanently soldered into a design. If you’ve got a particularly good idea where these chips would prove useful, sound off in the comments. Video after the break.

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Analyzing The “Source Code” Of The COVID-19 Vaccine

Computer programs are written in code, which comes in many forms. At the lowest level, there’s machine code and assembly, while higher-level languages like C and Python aim to be more human-readable. However, the natural world has source code too, in the form of DNA and RNA strings that contain the code for the building blocks of life. [Bert] decided to take a look at the mRNA source code of Tozinameran, the COVID-19 vaccine developed by BioNTech and Pfizer.

The analysis is simple enough for the general reader, while nonetheless explaining some highly complex concepts at the cutting edge of biology. From codon substitutions for efficiency and the Ψ-base substitution to avoid the vaccine being destroyed by the immune system, to the complex initialisation string required at the start of the RNA sequence, [Bert] clearly explains the clever coding hacks that made the vaccine possible. Particularly interesting to note is the Prolase substitution, a technique developed in 2017. This allows the production of coronavirus spike proteins in isolation of the whole virus, in order to safely prime the immune system.

It’s a great primer and we can imagine it might inspire some to delve further into the rich world of genetics and biology. We’ve featured other cutting edge stories on COVID-19 too; [Dan Maloney] took a look at how CRISPR techniques are helping with the testing effort. If there’s one thing the 2020 pandemic has shown, it’s humanity’s ability to rapidly develop new technology in the face of a crisis.

The Mouth-Watering World Of NIST Standard Foods

The National Institute Of Standards and Technology was founded on March 3, 1901 as the National Bureau of Standards, taking on its current moniker in 1988. The organisation is charged by the government with ensuring the uniformity of weights and measures across the United States, and generally helping out industry, academia and other users wherever some kind of overarching standard is required.

One of the primary jobs of NIST is the production and sale of Standard Reference Materials, or SRMs. These cover a huge variety of applications, from steel samples to concrete and geological materials like clay. However, there are also edible SRMS, too. Yes, you can purchase yourself a jar of NIST Standard Peanut Butter, though you might find the price uncompetitive with the varieties at your local supermarket. Let’s dive into why these “standard” foods exist, and see what’s available from the shelves of our favourite national standards institute. Continue reading “The Mouth-Watering World Of NIST Standard Foods” →