One of the interesting things about living in modern times is that a confluence of the Internet and rapid changes in the electronics industry means that test gear that used to be astronomically priced is now super affordable. Especially if, like [Frankie Mashockie], you can do a little repair work. He picked up an HP6038A power supply for $50. We couldn’t find the original list price, but even refurbs from “professional” sources go for around $800. However, the $50 price came with a “for parts” disclaimer.
The power supply is autoranging. You usually think of that as a feature of meters. In a power supply, autoranging means the device can adjust the voltage based on load as you can see explained in the video below.
This week, Elliot sat down with Dan for the penultimate podcast of 2023, and what a week it was. We started with news about Voyager; at T+46 years from launch, any news tends to be bad, and the latest glitch has everyone worried. We also took a look at how close the OSIRIS-REx mission came to ending in disaster, all for want of consistent labels.
Elliot was charmed by a Cthulhu-like musical instrument, while Dan took a shine to a spark gap transmitter that’s probably on the FCC’s naughty list. Any sufficiently advanced technology is indistinguishably from magic, and we looked at the laser made possible by the magician-in-chief himself, C.V. Raman. Why would you stuff a PSU full of iron filings? Probably for the same reason you’d print fake markings on a 6502 chip. We also took a look at the chemistry and history of superglue, a paper tape reader that could lop off your arm, and rocket gas stations in space.
If you’ve got a so-called uninterruptible power supply (UPS) on your system, you’re probably painfully aware that the “uninterruptible” part has some pretty serious limits. Most consumer units are designed to provide power during a black out only long enough to gracefully shut down your system. But with a few hacks like these, you can stretch that time out and turn it into a long-endurance UPS.
As many good stories do, this one starts in the trash, where [MetaphysicalEngineer] spotted an APC home office-style UPS. It was clearly labeled “broken,” but that just turned out to be a dead battery. While he could have simply replaced it with a 12-volt sealed lead-acid battery, [Meta] knew that his computer setup would quickly deplete the standard battery. A little testing showed him that a car battery would extend the run time significantly, especially if he threw in some extra cooling for the onboard inverter.
His final design uses a marine deep-cycle battery in a plastic battery box with the UPS mounted on top. The vacated battery compartment made a great place to add a cooling fan, along with a clever circuit to turn it on only when the beeper on the UPS sounds, with a bonus volume control for the annoying sound. He also added accessories to the battery box top, including a voltmeter, a USB charger, and a switched 12-volt power outlet. And kudos for the liberal use of fuses in the build; things could get spicy otherwise. The video below shows the entire build along with all the testing. [MetaphysicalEngineer] managed to triple the estimated runtime for the load he’s trying to power, so it seems like a win to us.
If your needs run more toward keeping your networking gear running through a blackout, you might want to check out this inverter-less DC UPS.
Remember Dieselgate, the scandal where certain diesel vehicles would detect an emissions test, and run cleaner for it, “cheating” the test? Traingate may just put that one into perspective. We’ll tell the story from the beginning, but buckle up for a wild and astonishing ride. It all starts with Polish trains getting a maintenance overhaul. These trains were built by Newag, who bid on the maintenance contract, but the contract was won by another company, SPS. This sort of overhaul involves breaking each train into its components, inspecting, lubricating, etc, and putting it all back together again. The first train went through this process, was fully reassembled, and then refused to move. After exhausting all of the conventional troubleshooting measures, SPS brought in the hackers. Continue reading “This Week In Security: Traingate, DNS, And JMP Slides”→
Inspired by many months of hours-long load shedding in South Africa, [JGJMatt] decided to make a portable speaker that can play tunes for hours on a single charge and even charge off the integrated solar panel to top the charge off. None of this should sound too surprising, but what differentiates this speaker is the use of two beefy 400 F, 2.7 V supercapacitors in series rather than a lithium-ion battery on the custom PCB with the Ti TPA2013D1 Class-D mono amplifier.
Insides of the speaker prior to stuffing and closing.
The reason for supercapacitors is two-fold. The first is that their lifespan is much longer than that of Li-ion batteries, the second that they can charge much faster. The disadvantages of supercapacitors come in the form of their lower energy density and linear discharge voltage. For the latter issue the TPA2301D1 amplifier has a built-in boost converter for an input range from 1.8 – 5.5 V, and despite the lower energy density a solid 6 hours of playback are claimed.
Beyond the exquisitely finished 3D printed PETG shell and TPU-based passive bass radiator, the functionality consists out of a single full-range speaker and an analog audio input (TRS jack and USB-C). To add Bluetooth support [JGJMatt] created a module consisting out of a Bluetooth module that connects to the USB-C port for both power and analog audio input.
Charging the speaker can be done via the USB-C port, as well as via the solar panel. This means that you can plug its USB-C port into e.g. a laptop’s USB-C port and (hopefully) charge it and play back music at the same time.
For those feeling like replicating this feat, the Gerbers, bill of materials, enclosure STLs, and everything else needed can be be found in the tutorial.
We’re so used to reverb effects being simply another software plugin that it’s easy to forget the electromechanical roots of the effect. Decades ago, a reverb would have been a metal spring fed at one end with a speaker and attached at the other to a microphone. You may not see them often in the 2020s, which is probably why [Ham-made] has produced one. It’s not the type with a speaker providing the sound, though. Instead, this is a microphone in its own right with a built-in spring line.
Perhaps it’s not the best microphone possible, with a somewhat heavy diaphragm and 3D printed body. But the hand-wound spring transmits the sound down to a piezo disk which serves as the electrical element, and the whole thing screws together into quite the usable unit. There are a selection of sample MP3 files that provide an interesting set of effect-laden sounds, so if you fancy building one yourself, you can judge the results.
Learning to play an instrument takes a certain level of dedication — and you can add another layer of dedication on top of that when it’s an instrument not found at your local Guitar Center. But it’s an entirely new level of dedication when someone crafts the instrument from scratch. If you’re looking for an example, check out this custom wooden zither [Nicolas Bras] built from laser cut parts.
The basic design of the instrument utilizes the sloted interlocking edges that are then glued together in lieu of traditional fasteners. Standard sized guitar tuning pegs and the accompanying steel guitar strings were then strung across two laser-cut bridges held in place by the string tension alone. The project began as way for [Nicolas] to learn the capabilities of his newly acquired laser cutter, but he himself is no amateur when it comes to constructing one-of-a-kind musical instruments. Just last year, he created a zither with bungee cords from the hardware store.
Zithers are German in origin, though some of the earliest zither-like instruments date back to 400 BCE China. The laser cut version [Nicolas] created had five strings to hammer on, though the type used in classical music arrangements typically contain upwards of thirty strings. The zither family of instruments may have given way to the electric guitars of today — it’s always neat to see new tech leveraged to embrace some old world charm.
