Small Spotify Remote Broadens Musical Horizons

When was the last time you tried listening to a new genre of music, or even explored a sub-genre of something you already like? That’s what we thought. It’s good to listen to other stuff once in a while and remind ourselves that there’s a whole lot of music out there, and our tastes are probably not all that diverse. As a reminder, [sorghum] made a spiffy little Spotify remote that can cruise through the musical taxonomy that is Every Noise at Once and control any Spotify-enabled device.

There’s a lot to like about this little remote, which is based upon a LilyGo TTGO ESP32 board with on-board display. The circuitry is basically that and a rotary encoder plus a tiny LiPo battery. Can we talk about the finish on those prints? Yes, those are both printed enclosures. Getting that buttery smooth finish took two grits of wet/dry sandpaper plus nine grits of polishing cloths.

As you can see in the brief demo after the break, there are several ways to discover new music. [sorghum] can surf through all kinds of Japanese music for example, or surf by the genre’s ending word and listen to metalcore, deathcore, and grindcore from all over the globe. For extra fun, there’s a genre-ending randomizer so you can discover just how many forms of *core there are.

Want everyone in the room to know what you’re listening to? Behold the Spotify split-flap display.

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A Battery To Add A Tingling Sensation To Your Tweets

Internet-connected sex toys are a great way to surprise your partner from work (even the home office) or for spicing up long-distance relationships. For some extra excitement, they also add that thrill of potentially having all your very sensitive private data exposed to the public — but hey, it’s not our place to kink-shame. However, their vulnerability issues are indeed common enough to make them regular guests in security conferences, so what better way to fight fire with fire than simply inviting the whole of Twitter in on your ride? Well, [Space Buck] built just the right device for that: the Double-Oh Battery, an open source LiPo-cell-powered ESP32 board in AA battery form factor as drop-in replacement to control a device’s supply voltage via WiFi.

Battery and PCB visualization
Double-Oh Battery with all the components involved

In their simplest and cheapest form, vibrating toys are nothing more than a battery-powered motor with an on-off switch, and even the more sophisticated ones with different intensity levels and patterns are usually limited to the same ten or so varieties that may eventually leave something to be desired. To improve on that without actually taking the devices apart, [Space Buck] initially built the Slot-in Manipulator of Output Levels, a tiny board that squeezed directly onto the battery to have a pre-programmed pattern enabling and disabling the supply voltage — or have it turned into an alarm clock. But understandably, re-programming patterns can get annoying in the long run, so adding WiFi and a web server seemed the logical next step. Of course, more functionality requires more space, so to keep the AA battery form factor, the Double-Oh Battery’s PCB piggybacks now on a smaller 10440 LiPo cell.

But then, where’s the point of having a WiFi-enabled vibrator with a web server — that also happens to serve a guestbook — if you don’t open it up to the internet? So in some daring experiments, [Space Buck] showcased the project’s potential by hooking it up to his Twitter account and have the announcement tweet’s likes and retweets take over the control, adding a welcoming element of surprise, no doubt. Taking this further towards Instagram for example might be a nice vanity reward-system improvement as well, or otherwise make a great gift to send a message to all those attention-seeking people in your circle.

All fun aside, it’s an interesting project to remote control a device’s power supply, even though its application area might be rather limited due to the whole battery nature, but the usual Sonoff switches may seem a bit unfitting here. If this sparked your interest in lithium-based batteries, check out [Lewin Day]’s beginner guide and [Bob Baddeley]’s deeper dive into their chemistry.

A Beginner’s Guide To Lithium Rechargeable Batteries

Batteries were once heavy, awkward things, delivering only a limp amount of current for their size and weight. Thankfully, over time, technology has improved, and in 2020, we’re blessed with capable, high-power lithium polymer batteries that can provide all the power your mobile project could possibly need. There are some considerations one must make in their use however, so read on for a primer on how to properly use LiPos in your project!

So Many Types!

With the first commercial lithium-ion battery entering the market in 1991, the (nearly) 30 years since have seen rapid development. This has led to a proliferation of different technologies and types of battery, depending on construction and materials used. In order to treat your batteries properly, it’s important to know what you’ve got, so paying attention to this is critical. Continue reading “A Beginner’s Guide To Lithium Rechargeable Batteries”

Better Battery Management Through Chemistry

The lead-acid rechargeable battery is a not-quite-modern marvel. Super reliable and easy to use, charging it is just a matter of applying a fixed voltage to it and waiting a while; eventually the battery is charged and stays topped off, and that’s it. Their ease is countered by their size, weight, energy density, and toxic materials.

The lithium battery is the new hotness, but their high energy density means a pretty small package that can get very angry and dangerous when mishandled. Academics have been searching for safer batteries, better charge management systems, and longer lasting battery formulations that can be recharged thousands of times, and a recent publication is generating a lot of excitement about it.

Consider the requirements for a battery cell in an electric car:

  • High energy density (Lots of power stored in a small size)
  • Quick charge ability
  • High discharge ability
  • MANY recharge cycles
  • Low self-discharge
  • Safe

Lithium ion batteries are the best option we have right now, but there are a variety of Li-ion chemistries, and depending on the expected use and balancing and charging, different chemistries can be optimized for different performance characteristics. There’s no perfect battery yet, and conflicting requirements mean that the battery market will likely always have some options.

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Teardown: Catel CTP300 Restaurant Pager

I have a problem. If I go to a swap meet , or even a particularly well stocked yard sale, I feel compelled to buy something. Especially if that something happens to be an oddball piece of electronics. While on the whole I’m a man of few vices, I simply can’t walk away from a good deal; doubly so if it has a bunch of buttons, LEDs, and antennas on it.

Table for one, by the window.

Which is exactly how I came into the possession of a Catel CPT300 restaurant paging system for just $20 a few months ago. I do not, as you may have guessed, operate a restaurant. In fact, as many of my meals take the form of military rations eaten in front of my computer, I’m about as far away from a restaurateur as is humanly possible. But I was so enamored with the rows of little plastic pagers neatly lined up in their combination charging dock and base station that I had to have it.

The man selling it swore the system worked perfectly. Even more so after he plugged it in and it didn’t do anything. But appearances can be deceiving, and his assurance that all the pagers needed was a good charge before they’d burst back to life seemed reasonable enough to me. Of course, it hardly mattered. The regular Hackaday reader at this point knows the fate of the CPT300 was to be the same whether or not it worked.

Incidentally, those cute little pagers would not burst back to life with a good charge. They may well have burst into something, but we’ll get to that in a moment. For now, let’s take a look at a gadget that most of us have used at one time or another, but few have had the opportunity to dissect.

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Replacement Batteries For The Sony Discman

Some of the first Sony Discmans included rechargeable batteries. These batteries were nickel metal hydride batteries (because of the technology of the time) and are now well past their service life. The new hotness in battery technology is lithium — it offers greater power density, lighter weight, and a multitude of ready-to-go, off the shelf cells. What if someone were to create a new battery pack for an old Sony Discman using lithium cells? That’s exactly what [sjm4306] did for their entry into this year’s Hackaday Prize.

The Discman [sjm] is working with uses a custom, Sony-branded battery based on NiMH technology with a capacity of around 500 mAH. After carefully measuring the dimensions of this battery, it was replicated in plastic with a 3D printer. This enclosure was then stuffed with a small lithium cell scavenged from a USB power bank.

The only tripping points for this build were the battery contacts. The originally battery had two contacts on the end that fit the Discman exactly; these were replicated with a small PCB wired up to the guts of the USB powerbank. The end result is a direct, drop-in replacement for the original Discman battery with a higher capacity, that’s also rechargeable via USB. It’s a fantastic project, with the entire build video available below.

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