Author: Brian McEvoy

266 Articles

Tube Tumbler Provides The Perfect Culture

March 27, 2022 by 2 Comments

We’ve all had to shake jars of nail polish, model paint, or cell cultures. Mixing paint is easy – but bacteria and cells need to be agitated for hours.  Happily, laboratory tube tumblers automate this for us. The swishing action is handled with rotation. The vials are mounted at angles around a wheel. The angular offset means the tubes are inclined as they rise, and declined as they fall. This causes the liquid in the tube to slosh from one side to the other as the wheel rotates.  [Sebastian S. Cocioba] aka [ATinyGreenCell] released his plans through Tinkercad and GitHub, and with a name like Sir Tumbalot, we know he must be cultured indeed.

Grab your monocles. Version 2 features a driven wheel lined with magnets to attach tube adapters, and he’s modeled 50mL and twin 15mL tube holders. The attachment points look like a simple beveled rectangle with a magnet pocket, so if you’re feeling vigorous for vials, you can whip up custom sockets and tumble any darn thing. A Trinamic StealthChop chip on a custom PCB controls the pancake stepper, and the whole shebang should cost less than $50USD. We’re wondering what other purposes this modular design could have, like the smallest rock tumbler or resin print rinser.

Making lab equipment is phenomenal for saving money for things that just spin up to a biotech lab.

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Jet burner and close-up

$7 Tent Heater Provides Comfort On A Budget

January 6, 2022 by 120 Comments

At Hackaday’s Minnesota office, we appreciate central heat and hot coffee because the outdoor temperature is sub-zero in Celsius and Fahrenheit. Not everyone here has such amenities, and families living in tents could use heater help. If you live somewhere inhospitably cold and have the resources (time being the most crucial), please consider building and donating alcohol jet burners.

Alcohol burners like these are great for tents because if they tip over, they self-extinguish. You can fill them with 70% rubbing alcohol and they’ll heat a small space, and if running on denatured alcohol, they can be used to cook with. They won’t do you much good outdoors unless you have significant wind protection, as the tiny jet is likely to blow out. The first time you light one, you must heat the coil with a lighter or another heater to vaporize incoming fuel, then it can sustain itself by wicking fluid up from the reservoir jar. Relighting after a tip or accidental gust only takes a spark since the copper is already hot.

If you came for a hack, note how they fill the small tubes with salt funneled through a condiment cap before bending them. Sure, there are springy pipe bending tools, but who doesn’t already have salt and tape? Keeping humans warm is crucial, but heating metal takes a different approach.

Thank you for the tip, [cyberlass]

USB to Dupont adapter by [PROSCH]

USB Power Has Never Been Easier

January 5, 2022 by 48 Comments

USB cables inevitably fail and sometimes one end is reincarnated to power our solderless breadboards. Of course, if the cable broke once, it is waiting to crap out again. Too many have flimsy conductors that cannot withstand any torque and buckle when you push them into a socket. [PROSCH] has a superior answer that only takes a couple of minutes to print and up-cycles a pair of wires with DuPont connectors. The metal tips become the leads and the plastic sheathing aligns with the rim.

The model prints with a clear plus sign on the positive terminal, so you don’t have to worry about sending the wrong polarity, and it shouldn’t be difficult to add your own features, like a hoop for pulling it out, or an indicator LED and resistor. We’d like to see one with a tiny fuse holder.

If you want your breadboard to have old-school features, like a base and embedded power supply, we can point you in the right direction. If you are looking to up your prototyping game to make presentation-worthy pieces, we have a host of ideas.

Attack Of The Eighty-Foot String Shooter

January 1, 2022 by 24 Comments

String shooters are exciting because they adhere to the laws of physics in that peculiar way that makes us ask, “How?” and “Why?” After a bit of poking and prodding, maybe some light rope burn, we probably have a few ideas on how we’d make our own. [Nick Belsten] and [Joey Rain] saw some desktop models and thought, “Let’s make that puppy eighty feet long!” Video also embedded after the break.

Instead of hobby motors, flashlight batteries, and toy car wheels, they choose a washing machine motor and bike tires, then plug into an extension cord. The three-minute video isn’t a how-to build because once you start welding this kind of hardware together, you are already flying by the seat of your pants. You will see a front yard with people delighting in the absurdity of launching rope continuously over the treetops. There’s plenty of room for observing a wave traveling along the cord or polishing your fingernails in a hurry.

We want to make string shooters for the office and add our personal flavor, like lights or colored string so they’re safe to touch. If you have a unique twist on any physics experiments, drop us a line, but for insurance reasons, we’ll add that you should not make a chainsaw without a guide bar, aka, the forbidden chain-saber.

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Jared Holladay

The Safest Model Roller Coaster

December 2, 2021 by 9 Comments

[Jared Holladay] is a computer engineering student at the University of Cincinnati and a life-long roller coaster fanatic. A lot of people look at roller coasters as an exciting example of physics, like potential energy versus kinetic energy or inertia, and rightly so. [Jared] looks at them and wonders about the controls. Video also below and there is a feature-length explanation with more details. Some Hackaday readers and writers can identify the components, so we think his coaster model belongs here.

Like many folks in this field, he’s built K’nex models to get a handle on construction. He’s toured STEM shows with the tracks and undoubtedly wowed kids, adults, and physics teachers, but since he can speak to the programming, he is a triple threat. Now, he’s growing out of the toy construction plastic and moving into 3D printed parts with needle-fine tolerances.

His latest base is extruded aluminum, like what you’d want in a rigid CNC or printer. In addition to the industrial-grade surface, Rockwell Automation sent him a safety programmable logic controller, PLC, and a touchscreen HMI. Our fellows in the industry tell us those are far beyond the price scope of regular hobbyists. But fear not; your Arduino clones will suffice until you get your first grant.

The point of all the ruggedized hardware, aside from authenticity, is to implement safety features the same way you would in the industry. The redundant PLC connects to inductive prox sensors to check train speed and location. Other moving parts, like friction brakes, have sensors to report if there is a jam. After all, it’s no good if you can’t stop a train full of people. There are hundreds of things that can go wrong. Just ask [Jared] because he programmed on-screen indicators for all of them and classified them to let an operator know if they can keep the ride moving or if they need to call maintenance.

Not all homemade coasters are scale models, and some of the traditional ones have more than meets the eye.

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Several frames from Bad Apple

PineTime Smartwatch And Good Code Play Bad Apple

October 16, 2021 by 11 Comments

PineTime is the open smartwatch from our friends at Pine64. [TT-392] wanted to prove the hardware can play a full-motion music video, and they are correct, to a point. When you watch the video below, you should notice the monochromatic animation maintaining a healthy framerate, and there lies all the hard work. Without any modifications, video would top out at approximately eight frames per second.

To convert an MP4, you need to break it down into images, which will strip out the sound. Next, you load them into the Linux-only video processor, which looks for clusters of pixels that need changing and ignores the static ones. Relevant pixel selection takes some of the load off the data running to the display and boosts the fps since you don’t waste time reminding it that a block of black pixels should stay the way they are. Lastly, the process will compress everything to fit it into the watch’s onboard memory. Even though it is a few minutes of black and white pictures, compiling can take a couple of hours.

You will need access to the watch’s innards, so hopefully, you have the developer kit or don’t mind cracking the seal. Who are we kidding, you aren’t here for intact warranties. The video resides in the flash chip and you have to transfer blocks one at a time. Bad Apple needs fourteen, so you may want to practice on a shorter video. Lastly, the core memory needs some updating to play correctly. Now you can sit back and…watch.

Pine64 had a rough start with the single-board computers, but they’re earning our trust with things like soldering irons and Google-less Linux mobile phones.

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100% display from filter screen and the responsible mod chip

Clearing The Air About Proprietary Consumables With A Xiaomi Filter DRM Resetter

August 28, 2021 by 16 Comments

The “razor and blades model” probably set a lot of young hackers on their current trajectory. If we buy a widget, we want to pick our widget refills instead of going back to the manufacturer for their name-brand option. [Flamingo-Tech] was having none of it when they needed a new filter for their Xiaomi air purifier so they set out to fool it into thinking there was a genuine replacement fresh from the box. Unlike a razor handle, the air purifier can refuse to work if it is not happy, so the best option was to make a “mod-chip.”

The manufacturer’s filters have a Near-Field Communication (NFC) chip and antenna which talk to the base station. The controller receives the filter data via I2C, but the mod-chip replaces that transmitter and reassures the controller that everything is peachy in filter town. On top of the obvious hack here, [Flamingo-Tech] shows us how to extend filter life with inexpensive wraps, so that’s a twofer. You can create your own mod-chip from the open-source files or grab one from [Flamingo-Tech’s] Tindie store.

We usually hear about mod-chips in relation to games, but we are happy to extend that honor to 3D printers. Have you ever fooled a “razor?”

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