Homebrew PH Meter Uses Antimony Electrode

November 15, 2024 by Dan Maloney 11 Comments

Understanding the nature of pH has bedeviled beginning (and not-so-beginning) chemistry students for nearly as long as chemistry has had students. It all seems so arbitrary, being the base-10 log of the inverse of hydrogen ion concentration and with a measurement range of 0 to 14. Add to that the electrochemical reactions needed to measure pH electronically, and it’s enough to make your head spin.

Difficulties aside, [Markus Bindhammer] decided to tackle the topic and came up with this interesting digital pH meter as a result. Measuring pH electronically is all about the electrode, or rather a pair of electrodes, one of which is a reference electrode. The potential difference between the electrodes when dipped into the solution under test correlates to the pH of the solution. [Markus] created his electrode by drawing molten antimony into a length of borosilicate glass tubing containing a solid copper wire as a terminal. The reference electrode was made from another piece of glass tubing, also with a copper terminal but filled with a saturated solution of copper(II) sulfate and plugged with a wooden skewer soaked in potassium nitrate.

In theory, this electrode system should result in a linear correlation between the pH of the test solution and the potential difference between the electrodes, easily measured with a multimeter. [Marb]’s results were a little different, though, leading him to use a microcontroller to scale the electrode output and display the pH on an OLED.

The relaxing video below shows the build process and more detail on the electrochemistry involved. It might be worth getting your head around this, since liquid metal batteries based on antimony are becoming a thing.

Continue reading “Homebrew PH Meter Uses Antimony Electrode” →

Desert Island Acetylene From Seashells And Driftwood

November 15, 2024 by Dan Maloney 35 Comments

[MacGyver] would be proud of [Hyperspace Pirate]’s rough and ready method of producing acetylene gas from seashells and driftwood.

Acetylene, made by decomposing calcium carbide with water, is a vitally important industrial gas. Not only as a precursor in many chemical processes, but also as the fuel for the famous “blue wrench,” a tool without which auto mechanics working in the Rust Belt would be reduced to tears. To avoid this, [Hyperspace Pirate] started by beachcombing for the raw materials: shells to make calcium oxide and wood to make charcoal. Charcoal is pretty easy; you just cook chunks of wood in a reducing environment to drive off everything but the carbon. Making calcium oxide from the calcium carbonate in the shells isn’t much harder, with ground seashells heated in a propane-fired furnace to release carbon dioxide.

With the raw ingredients in hand, things get a little tricky. Making calcium carbide requires a lot of heat, far more than a simple propane burner can provide. [Hyperspace Pirate] decided to go with an electric arc furnace, to which end he cannibalized a 120 V to 240 V step-up converter for its toroidal transformer, which with a few extra windings provided the needed current to run an arc through carbon electrodes. This generated the needed heat, and then some, as the ceramic firebrick he was using to contain the inferno melted. After rewinding the melted secondary windings on his makeshift transformer and switching to a stainless steel crucible, he was able to make enough calcium carbide to generate an impressive amount of acetylene. The video below documents the process and the sooty results, as well as details a little of the excitement that metal acetylides offer.

For more about acetylene and its many uses, [This Old Tony] has you covered.

Continue reading “Desert Island Acetylene From Seashells And Driftwood” →

Retro Calculator Build Proves The Space Age Isn’t What It Used To Be

November 14, 2024 by Dan Maloney 20 Comments

The common wisdom these days is that even if we wanted to get back to the Moon the way we did in the 1960s, we’d never be able to do it. Most of the blame for that usually falls on the loss of institutional knowledge thanks to skilled minds and hands that have been stilled by the passage of time, but the real kicker would be finding replacements for all the parts that we used back then that just aren’t made anymore. A similar problem exists for those seeking to recreate the circuits that graced the pages of the many magazines that catered to electronics hobbyists back in the day.

Take this “Space Age Decimal Computer” reproduction that [Bob Alexander] undertook. Smitten with the circuit after seeing our story about a 1966 article detailing its construction, he decided to roll one of his own. That proved to be far harder than he thought it would be. The original circuit, really little more than an adding machine using a rotary telephone dial as an input device, used neon lamp ring buffers for counting, The trouble is, while NE-2 neon lamps are still made, they aren’t made very precisely. That makes it difficult to build a working ring buffer, which relies on precise on and off voltages. That was even a problem back then; the author suggested buying 100 lamps and carefully characterizing them after aging them in to get the 60 lamps needed.

In the end, [Bob] settled for modifying the circuit while making the build look as close as possible to the original. He managed to track down the exact model of enclosure used in the original. The front panel is populated with a rotary dial just like the original, and the same neon lamps are used too, but as indicators rather than in ring buffers. Behind the scenes, [Bob] relied on 7400-series counters and decoders to make it all work — kudos for sticking with 1970s tech and not taking the easy way out with an Arduino.

The video below goes into more detail on the build and the somewhat kludgy operation of the machine, with a few excellent [Tom Lehrer] references and a nice Cybertruck dunk to boot.

Continue reading “Retro Calculator Build Proves The Space Age Isn’t What It Used To Be” →

Nebraskan Farmers Were Using Wind Turbines Before Environmentalism Was Invented

November 14, 2024 by Jenny List 18 Comments

To a casual observer of public discourse here in 2024 it seem extremely odd that the issue of replacing coal fired power stations with wind turbines is a matter of controversy, whether in America or Europe it’s an issue which causes some sparks to fly. The Atlantic has a recent article with a set of pictures from a gentler time in which the industrious nature of Nebraskan farmers in the 1890s receives praise as they create a wide variety of home-made wind turbines.

Farmers have always been the best hardware hackers, using what they have at hand to solve their problems and create the things they need. Perhaps out image of agricultural wind power is one of commercially produced wind pumps, but these are the generation of home-made devices which preceded that. Some of them look conventional to modern eyes, but others such as the horizontal “Jumbo” turbines have little equivalent today.

It’s easy to forget with so many energy sources at our disposal, that in the past the locality affected the choice of motive power. The Netherlands doesn’t have windmills because they are pretty, but because hundreds of years ago they lacked handy coal mines or convenient heads of water. Similarly out in the Nebraskan prairies they had plenty of wind, and never the folk to pass up on an opportunity, they made the best of it. And we’re very glad over a century later, that someone took the time to record their work.

If you’re hungry for more old-style wind power, we’ve got you covered, meanwhile 19th century America was no stranger to clever ways to use power.

Thanks [Hugh Brown] for the tip.

Repairing The Questionable £25,000 Tom Evans Audiophile Pre-Amp

November 14, 2024 by Maya Posch 123 Comments

One of the power supply boards in the Tom Evans Mastergroove SR MkIII preamplifier. (Credit: Mend it Mark, YouTube)

It’s not much of a secret that in the world of ‘audiophile gear’ there is a lot of snake oil and deception, including many products that are at best of questionable value. The Tom Evans Mastergroove SR mkIII preamplifier is one example of this, as [Mark] from the Mend it Mark YouTube channel found in a recent video when he got one to repair which the manufacturer claimed ‘could not be fixed’. This marvel of audio engineering provides amplification for record players, for the low-low price of only twenty-five thousand quid, or about 29.000 US bucks. So what’s inside one of these expensive marvels?

Claiming to be a high-end unit, with only ten units produced per year, you’d expect a gold-plated PCB with excellent noise isolation. The unit does come with an absolutely massive external power supply that dwarfs the preamplifier itself, but the real surprise came after opening up the unit itself to take a peek at the damage, some of which was caused by transport.

As it turns out, the inside of the preamplifier consists out of four stacks of rather cheap, home-made looking boards with what looks like improvised RF shielding in the form of bare PCBs and filed-off markings on many parts. In between the rat’s nest of wiring running everywhere, [Mark] had to trace the broken channel’s wiring, creating a full repair manual in the process. Along the way one of the opamp boards was found to be defective, courtesy of a single shorted tantalum capacitor.

With the tantalum capacitor replaced, [Mark] had repaired the unit, but even though the preamplifier isn’t terribly designed, the illusion of its price tag has been shattered worse than the contents of a parcel kicked across the parking lot by the Royal Mail.

Thanks to [Jim] for the tip.

Continue reading “Repairing The Questionable £25,000 Tom Evans Audiophile Pre-Amp” →

Bluetooth Dongle Gives Up Its Secrets With Quick Snooping Hack

November 14, 2024 by Dan Maloney 5 Comments

There’s a lot going on in our wireless world, and the number of packets whizzing back and forth between our devices is staggering. All this information can be a rich vein to mine for IoT hackers, but how do you zero in on the information that matters? That depends, of course, but if your application involves Bluetooth, you might be able to snoop in on the conversation relatively easily.

By way of explanation, we turn to [Mark Hughes] and his Boondock Echo, a device we’ve featured in these pages before. [Mark] needed to know how long the Echo would operate when powered by a battery bank, as well as specifics about the power draw over time. He had one of those Fnirsi USB power meter dongles, the kind that talks to a smartphone app over Bluetooth. To tap into the conversation, he enabled Host Control Interface logging on his phone and let the dongle and the app talk for a bit. The captured log file was then filtered through WireShark, leaving behind a list of all the Bluetooth packets to and from the dongle’s address.

That’s when the fun began. Using a little wetware pattern recognition, [Mark] was able to figure out the basic structure of each frame. Knowing the voltage range of USB power delivery helped him find the bytes representing voltage and current, which allowed him to throw together a Python program to talk to the dongle in real-time and get the critical numbers.

It’s not likely that all BLE-connected devices will be as amenable to reverse engineering as this dongle was, but this is still a great technique to keep in mind. We’ve got a couple of applications for this in mind already, in fact.

Continue reading “Bluetooth Dongle Gives Up Its Secrets With Quick Snooping Hack” →

The Diablo Canyon NPP in California. This thermal plant uses once-through cooling. (Credit: Doc Searls)

US DOE Sets New Nuclear Energy Targets

November 14, 2024 by Navarre Bartz 63 Comments

To tackle the growing electrification of devices, we’ll need to deploy more generation to the grid. The US Department of Energy (DOE) has unveiled a new target to triple nuclear generating capacity by 2050.

Using a combination of existing Generation III+ reactor designs, upcoming small modular and micro reactors, and “legislation like the ADVANCE Act that streamlines regulatory processes,” DOE plans to add 35 gigawatt (GW) of generating capacity by 2035 and an additional 15 GW installed per year by 2040 to hit a total capacity of 200 GW of clean, green atom power by 2050.

According to the DOE, 100 GW of nuclear power was deployed in the 1970s and 1980s, so this isn’t an entirely unprecedented scale up of nuclear, although it won’t happen overnight. One of the advantages of renewables over nuclear is the lower cost and better public perception — but a combination of technologies will create a more robust grid than an “all of your eggs in one basket” approach. Vehicle to grid storage, geothermal, solar, wind, and yes, nuclear will all have their place at the clean energy table.

If you want to know more about siting nuclear on old coal plants, we covered DOE’s report on the matter as well as some efforts to build a fusion reactor on a decommissioned coal site as well.