Better Battery Design Through Science

Before the age of lithium batteries, any project needing to carry its own power had to rely on batteries that were much less energy-dense and affordable. In many ways, we take modern lithium technology for granted, and can easily put massive batteries in our projects by the standards of just a few decades ago. While the affordability of lithium batteries has certainly decreased the amount of energy we need to put in to our projects to properly size batteries, there’s still a lot of work to be done if you’re working on a bigger project or just want to get the maximize the efficiency and effectiveness of your DIY battery pack.

The main problem with choosing a battery, as [ionworks] explains, is that batteries can’t be built for both high energy and high power, at least not without making major concessions for weight or cost. After diving in to all of the possible ways of customizing a battery, the battery guide jumps in to using PyBaMM to perform computational modeling of potential battery designs to hopefully avoid the cumbersome task of testing all of the possible ways of building a battery. With this tool virtually all of a battery’s characteristics can be simulated and potential problems with your setup can be uncovered before you chose (or start production of) a specific battery system.

While customizing a battery pack to this extent might not be a consideration for most of us unless the project is going to be big enough to run something like an electric car or a whole-house generator, it’s a worthwhile tool to know about as even smaller projects like ebikes can benefit from choosing the right cell for the application. Some of the nuances of battery pack design can be found in this guide to building packs from the standard 18650 cells.

Header: Lead holder, CC BY-SA 3.0 .

Taco Bell To Bring Voice AI Ordering To Hundreds Of US Drive-Throughs

Drive-throughs are a popular feature at fast-food places, where you can get some fast grub without even leaving your car. For the fast-food companies running them they are also a big focus of automation, with the ideal being a voice assistant that can take orders and pass them on to the (still human) staff. This probably in lieu of being able to make customers use the touch screens-equipped order kiosks that are common these days. Pushing for this drive-through automation change is now Taco Bell, or specifically the Yum Brands parent company.

This comes interestingly enough shortly after McDonalds deemed its own drive-through voice assistant to be a failure and removing it. Meanwhile multiple Taco Bell in the US in 13 states and five KFC restaurants in Australia are trialing the system, with results apparently encouraging enough to start expanding it. Company officials are cited as it having ‘improved order accuracy’, ‘decreased wait times’ and ‘increased profits’. Considering the McDonalds experience which was pretty much the exact opposite in all of these categories we will remain with bated breath. Feel free to share your Taco Bell or other Voice AI-enabled drive-through experiences in the comments. Maybe whoever Yum Brands contracted for their voice assistant did a surprisingly decent job, which would be a pleasant change.

Top image: Taco Bell – Vadnais Heights, MN (Credit: Gabriel Vanslette, Wikimedia)

Bright green shelving units suspended with silver hardware from a black frame. They are against a dark wooden wall.

Sliding Shelves Supersize Storage

Organizing things in your home or workshop is a constant battle for some of us. Until we have access to a Tardis or bag of holding, maybe the next best thing is a sliding shelf system.

[HAXMAN] found a great set of sliding shelves online, but after recovering from sticker shock decided he could build something similar for much less. The frame for the shelving was built from 4×4 posts, some 2x4s, and strut channel track welded to steel 2x6s. Aluminum plates bolted to strut trolleys support the weight of the shelving units he built from plywood.

Everything was painted with a multi-material paint formulated for covering both wood and metal so everything has a uniform appearance. We love the bright shelving offset by the more classic black appearance of the rack. Just because its storage, doesn’t mean it has to look boring!

Looking for more clever storage solutions? You might like your to make your own shadow boards, favor Gridfinity, or just wonder what other readers do to organize their electronic odds and ends.
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Custom Hat Gives Vintage Mitutoyo Calipers A New Lease On Life

Metrology fans are usually at least a little bit in love with Mitutoyo, and rightfully so. The Japanese company has been making precision measuring instruments for the better part of 100 years, and users appreciate their precision almost as much as the silky smooth feel of their tools. If you can afford it, a Mitutoyo caliper is quite an addition to your toolbox.

As good as they are, though, they’re not perfect, which is what led to this clever Mitutoyo digital caliper hack by [turbanedengineer]. The calipers in question, a digital set from the early 1980s, happen to have a unique history with a tangential Hackaday angle — they belonged to [Dhaval], mechanical engineer and avid motorcyclist who happens to be the late elder brother of our own [Anool Mahidharia].

The tool, in need of a little TLC, made its way to [turbanedengineer] who first restored the broken battery contacts. Once powered up again, it became apparent that while the caliper’s native metric measurements were spot on, the internal conversion to inches was considerably off. This led [turbanedengineer] to the data port on the tool, which is intended to send serial data to an external computer for logging measurements. After a little experimentation to nail down the data format, he prototyped a tiny circuit using an ATtiny85 and an OLED display that reads the caliper data, converts metric to inches, and displays both measurements on the screen. The prototype led to a more permanent version, which cleverly sits over the original display and taps into the data port without any free wires. The video below shows the very slick results.

Our hearts go out to [Anool] and his family for their loss, and we tip our hats to [turbanedengineer] for his thoughtful and respectful hack of a storied tool. We know that anthropomorphizing tools makes no rational sense, but we think it’s safe to say that a tool like this has a soul, and it’s probably happy to be back in the game.

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Over-molding Wires With Hot Glue And 3D Printed Molds

We’ve said it before and we’ll say it again: water always finds a way in. That’s particularly problematic for things like wire splices in damp environments, something that no amount of electrical tape is going to help. Heat shrink tubing might be your friend here, but for an electrically isolated and mechanically supported repair, you may want to give over-molding with a hot glue gun a try.

The inspiration for [Print Practical]’s foray into over-molding came from a video that’s making the rounds showing a commercially available tool for protecting spliced wires in the automotive repair trade. It consists of a machined aluminum mold that the spliced wires fit into and a more-or-less stock hot glue gun, which fills the mold with melted plastic. [Print Practical] thought it just might be possible to 3D print custom molds at home and do it himself.

His first attempt didn’t go so well. As it turns out, hot glue likes to stick to things — who knew? — including the PETG mold he designed. Trying to pry apart the mold after injection was a chore, and even once he got inside it was clear the glue much preferred to stay in the mold. Round two went much better — same wire, same mold, but now with a thin layer of vegetable oil to act as a release agent. That worked like a charm, with the over-mold standing up to a saltwater bath with no signs of leaking. [Print Practical] also repaired an iPhone cable that has seen better days, providing much-needed mechanical support for a badly frayed section.

This looks like a fantastic idea to file away for the future, and one that’s worth experimenting with. Other filament types might make a mold better able to stand up to the hot glue, and materials other than the ethylene-vinyl acetate copolymer found in most hot glue sticks might be explored. TPU over-molds, anyone? Or perhaps you can use a printer as an injector rather than the glue gun.

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Hackaday Podcast Episode 282: Saildrones, A New Classic Laptop, And SNES Cartridges Are More Than You Think

In this episode, the CrowdStrike fiasco has Hackaday Editors Elliot Williams and Tom Nardi pondering the fragility of our modern infrastructure. From there the discussion moves on to robotic sailboats, the evolving state of bespoke computers, and the unique capabilities of the Super Nintendo cartridge. You’ll also hear about cleaning paintings with lasers, the advantages of electronic word processors, stacking 3D printed parts, and the joys of a nice data visualization. They’ll wrap the episode up by marveling at the techniques required to repair undersea fiber optic cables, and the possibilities (and frustrations) of PCB panelization using multiple designs.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

As always, the Hackaday Podcast is available in DRM-free MP3 for offline listening.

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A circular concrete pond in a garden. A small round fountain jets water out in the center and a solar panel and control box are visible attached to the end of the pond opposite the camera. On the top left is the text, "3D printed, Solar powered, and Arduino controlled" in yellow

Solar Fountain Aerates Garden Pond

Sometimes off-the-shelf solutions to a problem don’t meet your expectations. That’s what led [TomGoff] to build his own solar pond fountain.

This build features a lot of creative reuse of materials [TomGoff] already had on hand, like the end of a cable reel for the platform and a wheelbarrow inner tube for flotation. A 3D printed nozzle in the center of this apparatus is attached to a 12 V water pump and the whole thing is controlled by an Arduino running 30 seconds on and 3 minutes off to conserve battery power.

A hand-built perfboard contains a light dependent resistor (LDR) to tell the Arduino not to run at night, the relay for the pump, and a battery charge monitor. Be sure to check out the full write-up to see the video of the Tinkercad electronics simulation as well as the code. A 20 W solar panel keeps the whole thing charged so you don’t have to run mains power out to your pond.

If you need more solar projects for your garden, how about this Charmander lamp or a solar powered irrigation system?

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