Sailor Hat Adds Graceful Shutdown To Pis

Even though Windows and other operating systems constantly remind us to properly eject storage devices before removing them, plenty of people won’t heed those warnings until they finally corrupt a drive and cause all kinds of data loss and other catastrophes. It’s not just USB jump drives that can get corrupted, though. Any storage medium can become unusable if certain actions are being taken when the power is suddenly removed. That includes the SD cards on Raspberry Pis, too, and if your power isn’t reliable you might consider this hat to ensure they shut down properly during power losses.

The Raspberry Pi hat is centered around a series of supercapacitors which provide power for the Pi temporarily. The hat also communicates with the Pi to let it know there is a loss of power, so that the Pi can automatically shut itself down in that situation to prevent corrupting the memory card. The hat is more than just a set of backup capacitors, though. The device is capable of taking input power from a wide range of sources and filtering it for the power requirements of the Pi, especially in applications like boats and passenger vehicles where the input power might be somewhat noisy. There’s an optocoupled CAN bus interface as well for those looking to use this for automotive applications.

The entire project is also available on the project’s GitHub page for those wishing to build their own. Some sort of power backup is a good idea for any computer, though, not just Raspberry Pis. We’ve seen uninterruptible power supplies (UPS) with enough power to run an entire house including its computers, to smaller ones that’ll just keep your Internet online during a power outage.

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Inside A Cordless Soldering Station

There was a time when soldering stations were unusual in hobby labs. These days, inexpensive stations are everywhere. [Kerry Wong] looks at the TS1C station, which is tiny and cordless. As he points out, cordless irons are not new, but modern battery technology has made them much more practical. However, this iron doesn’t actually have a battery.

The iron has a large 750 Farad supercapacitor. This has advantages and disadvantages. On the plus side, a supercapacitor charges quickly and doesn’t get weaker with each charging cycle like a conventional battery. On the minus side, the large capacitor makes the unit bulky compared to normal irons. [Kerry] notes that it is ergonomic, though, and he felt comfortable holding it. Also, the supercapacitor limits the amount of charge available while soldering.

It is somewhat of a balance, though. If you want to take the iron and climb a tower, you might be very interested in a longer running time. But if you return the unit to the base every few minutes, the fast charging of the cap will compensate for the lower capacity, and you’ll probably never notice it go flat.

The iron itself doesn’t display any data. The display is on the base, meaning the devices must be paired via Bluetooth. It also requires a PD-enabled USB-C connection, so you can’t just wire it to a battery. You can plug a power supply right into the iron if you prefer, but you still can’t use a simple power connection.

Of course, you assume it does an adequate job of soldering. We wanted to see inside! And [Kerry] didn’t disappoint. If you want to see soldering, skip to about the 10-minute marker. The teardown starts at around 16 minutes.

Honestly, for the bench, we’d probably stick with a wired iron. You don’t always want a base and a PD power supply for a portable iron. But if you absolutely hate cords, this could be a reasonable answer. We’ve seen another review of this iron that didn’t like the plastic casings. Maybe it is like Jedi and lightsabers: you should just build your own.

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MIT Cracks The Concrete Capacitor

It’s a story we’ve heard so many times over the years: breathless reporting of a new scientific breakthrough that will deliver limitless power, energy storage, or whichever other of humanity’s problems needs solving today. Sadly, they so often fail to make the jump into our daily lives because the reporting glosses over some exotic material that costs a fortune or because there’s a huge issue elsewhere in their makeup. There’s a story from MIT that might just be the real thing, though, as a team from that university claim to have made a viable supercapacitor from materials as simple as cement, carbon black, and a salt solution. Continue reading “MIT Cracks The Concrete Capacitor”

A loudspeaker with a supercapacitor PCB next to it

Hackaday Prize 2023: Supercapacitors Let Solar Speaker Work In Darkness

Solar panels are a great way to generate clean electricity, but require some energy storage mechanism if you also want to use their power at night. This can be a bit tricky for large solar farms that feed into the grid, which require enormous battery banks or pumped storage systems to capture a reasonable amount of energy. It’s much easier for small, handheld solar gadgets, which work just fine with a small rechargeable battery or even a big capacitor. [Jamie Matthews], for instance, built a loudspeaker that runs on solar power but can also work in the dark thanks to two supercapacitors.

The speaker’s 3D-printed case has a 60 x 90 mm2 solar panel mounted at the front, which charges a pair of 400 Farad supercaps. Audio input is either through a classic 3.5 mm socket or through the analog audio feature of a USB-C socket. That same USB port can also be used to directly charge the supercaps when no sunlight is available, or to attach a Bluetooth audio receiver, which in that case will be powered by the speaker.

A speaker's passive radiator next to a solar panel
The solar panel sits right next to the passive radiator before both are covered with speaker fabric.

The speaker’s outer shell, the front bezel, and even the passive radiator are 3D-printed and spray-painted. The radiator is made of a center cap that is weighed down by a couple of M4 screws and suspended in a flexible membrane. [Jamie] used glue on all openings to ensure the box remains nearly airtight, which is required for the passive radiator to work properly. Speaker fabric is used to cover the front, including the solar panel – it’s apparently transparent enough to let a few watts of solar power through.

A salvaged three-inch Bose driver is the actual audio source. It’s driven by a TI TPA2013D1 chip, which is a 2.7 W class-D amplifier with an integrated boost converter. This enables the chip to keep a constant output power level across a wide supply voltage range – ideal for supercapacitor operation since supercaps don’t keep a constant voltage like lithium batteries do.

[Jamie] has used the speaker for more than nine months so far and has only had to charge it twice manually. It probably helps that he lives in sunny South Africa, but we’ve seen similar solar audio projects work just fine in places like Denmark. If you’re taking your boombox to the beach, a sunscreen reminder feature might also come in handy.

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Hackaday Links: June 25, 2023

Is it really a dystopian future if the robots are radio-controlled? That’s what came to mind reading this article on a police robot out of Singapore, complete with a breathless headline invoking Black Mirror, which is now apparently the standard by which all dystopias are to be judged. Granted, the episode with the robo-dogs was pretty terrifying, but it seems like the Singapore Police Force has a way to go before getting to that level. The bot, which has been fielded at Changi Airport after extensive testing and seems to be completely remote-controlled, is little more than a beefy telepresence robot. At 5.5 feet (1.7 meters) tall, the bot isn’t terribly imposing, although it apparently has a mast that can be jacked up another couple of feet, plus there are lights, sirens, and speakers that can get the message across. Plus cameras, of course; there are always cameras. The idea is to provide extra eyes to supplement foot patrols, plus the potential to cordon off an incident until meatspace officers arrive. The buzzword game here is weak, though; there’s no mention of AI or machine learning at all. We have a feeling that when the robots finally rise up, ones like this will be left serving the drinks.

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Homemade Scope Does Supercapacitor Experiments

We’ve always been a little sad that supercapacitors aren’t marked with a big red S on a yellow background. Nevertheless, [DiodeGoneWild] picked up some large-value supercapacitors and used his interesting homemade oscilloscope to examine how they worked. You can watch what he is up to in his workshop in the video below.

Supercapacitors use special techniques to achieve very high capacitance values. For example, the first unit in the video is a 500 F capacitor. That’s not a typo — not microfarads or even millifarads — a full 500 Farads. With reasonable resistance, it can take a long time to charge 500F, so it is easier to see the behavior, especially with the homemade scope, which probably won’t pick up very fast signals.

For example, A 350 mA charging current takes about an hour to bring the capacitor up to 2.6 V, just under its maximum rating of 2.7 V. Supercapacitors usually have low voltage tolerance. Their high capacity makes them ideal for low-current backup applications where you might not want a rechargeable battery because of weight, heat, or problems with long-term capacity loss.

The real star of the video, though, is the cast of homemade test equipment, including the oscilloscope, a power supply, and a battery analyzer. To be fair, he also has some store-bought test gear, too, and the results seem to match well.

Supercapacitors are one of those things that you don’t need until you do. If you haven’t had a chance to play with them, check out the video or at least watch it to enjoy the homebrew gear. We usually look to [Andreas Spiess] for ESP32 advice, but he knows about supercaps, too. If you really like making as much as you can, you can make your own supercapacitors.

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Battery Engineering Hack Chat Gets Charged Up

Turn the clock back a couple of decades, and the only time the average person would have given much thought to batteries was when the power would go out, and they suddenly needed to juice up their flashlight or portable radio.  But today, high-capacity batteries have become part and parcel to our increasingly digital lifestyle. In fact, there’s an excellent chance the device your reading this on is currently running on battery power, or at least, is capable of it.

So let’s get to know batteries better. What’s the chemical process that allows them to work? For that matter, what even is a battery in the first place?

It’s these questions, and more, that made up this week’s Battery Engineering Hack Chat with Dave Sopchak. Our last Hack Chat of 2022 ended up being one of the longest in recent memory, with the conversation starting over an hour before the scheduled kickoff and running another half hour beyond when emcee Dan Maloney officially made his closing remarks. Not bad for a topic that so often gets taken for granted.

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