2026-03-27 16:00:27
Flow batteries are rather unique. They generate electricity by the combination of two fluids flowing on either side of a membrane. Typically, this involves the use of some kind of pump to get everything moving. However, [Dusan Caf] has demonstrated another way to make a flow battery operate.
[Dusan]’s build is a zinc-iodide flow battery. It uses two 3D printed reservoirs, each holding a ZnI2 solution and a graphite electrode. Unlike traditional flow batteries, there is no mechanism included to mechanically push the fluid around. Instead, fluid motion is generated by the magnetohydrodynamic effect, which you may know from that Japanese boat that didn’t work very well.
When charging the liquid-based cell, current flows through the conductive electrolyte that sits between both electrodes. This sees zinc electroplated onto the graphite anode, while iodide ions are oxidized at the cathode. There’s also a permanent magnet installed beneath the electrodes, which provides a stable magnetic field. This field, combined with the current flowing through the electrolyte, sees the Lorentz force pushing the electrolyte along, allowing the flow battery to operate. When the cell is being discharged, the reactions happen in reverse, with the flow through the electrodes changing direction in turn. Neatly, as current draw or supply increases, the flow rate increases in turn, naturally regulating the system.
[Dusan] notes this isn’t feasible for large batteries, due to the limited flow rate, but it’s fine for small-scale demos regarding the operation of a flow battery. We’ve featured some more typical flow battery designs in the past, too.
2026-03-27 13:00:55
You can certainly just chug down that bottle of soda you purchased, but if you accept the premise that the preparation of food and drink is just a subset of chemistry, and that chemistry is fun, then it naturally follows that using soda as the basis for brewing up some mead makes perfect sense. Thus the [Golden Hive Mead] blokes over on YouTube decided to create some Coca Cola flavored mead.
Mead is essentially just water mixed with honey that is left to ferment after adding yeast, resulting in what is also called ‘honey wine’, with an ethanol content of usually between 3.5% and 20%. Since soda is mostly water and comes with its own supply of sugar for yeast to feast on, this isn’t such a crazy choice in that respect. Just make sure to remove the carbonation, as the CO2 makes the soda too acidic for the yeast to be happy.
Instead of straight honey, caramelized honey was used for extra flavor after which the brew was left to ferment for a while. For extra flavor notes aged oak, vanilla and cinnamon were added as well, to ensure that the fermentation didn’t erase those core notes of the coke. The result was apparently rather flavorful, with about a 10.5% ethanol content, receiving the full approval of both tame test tasters.
2026-03-27 10:00:31
A lot of the time, we must assign our own meaning to the numbers on the clock. 8:30 AM is work kicking off, 12 PM is lunch, and 5PM is when the corporate chains release us to what’s left of the day. If you’d rather the clock tell you what’s special about the current time, though, you might like this project from [Andy Isaacson].
It’s called Momentous—”a clock to make every minute meaningful” in [Andy’s] own words. The concept is simple—for each minute, the clock digs up some random mathematical fact relevant to the current time. For example, you might think of 3:14 as Pi o’clock, but Momentous also notes that the sequence “314” shows up at the 856th decimal of e. Useful? Probably not. Fun? If you like numbers, then very!
[Andy] wrote Momentous in Typescript with React Native and Expo. Baked into the app is a computed list of fun number facts for every conceivable time from 00:00 to 23:59. All these timely numbers were processed through a “fact generation” algorithm to dig up mathly tidbits. Do they contain primes? Do the numbers show up in a famous irrational number sequence? Are they palindromic, or can some neat facts be gleaned from Wikipedia? Maybe the current time shows up in your best friend’s phone number! Momentous uses all these and more to make every minute of the day a little bit more interesting.
You can check out the clock for yourself in your web browser. Alternatively, you can install it on your iPhone if you so desire. We feature all kinds of fun clocks here, from the wordy to the absurdy. If you’re cooking up your own timely hacks, we always love to to hear about them on the tipsline!
2026-03-27 07:00:09
If you have a 12 VDC power system, like the battery of a PV solar system or car, would it be more efficient to boil water for that cup of tea with that 12V straight from the battery, or use a 240 VAC mains kettle via a ~90% efficient inverter instead? That’s the question that [Cahn] decided to answer experimentally, using a bulky 3 kW inverter and a collection of electric kettles.
Although the used amount of 500 mL of water is boiled much faster in the 2,200 Watt mains kettle than in the 150 and 350 Watt low-voltage kettles, this obvious difference is somewhat irrelevant if you’re only concerned with efficiency. To measure the power used a Victron smart shunt was used with each run, keeping in mind that a perfect efficiency for heating 500 mL from room temperature to boiling is around 43-44 Wh.
With two runs per kettle, the 240 VAC kettle used 65-70 Wh. The first ‘150 Watt’ kettle pulled nearly 200 Watt to boil the water after about 20 minutes, using 62-64 Wh. The second ‘150 Watt’ kettle pulled around 180 Watt, took 23-25 minutes and used 68-74 Wh. Finally, the ‘350 Watt’ kettle drew over 420 Watt and used 50-56 Wh in just over 8 minutes.
When you look at the final results, it’s interesting to note that the low-voltage kettles got both first and last place in this contest, even when factoring in the inverter losses for the 2.2 kW kettle. This makes it quite obvious that the issue at hand is less about DC vs AC or mains vs low-voltage.
The 350 Watt kettle is clearly better designed, featuring a level of insulation that the cheap 12V kettles lack, while pumping more energy into the water at a much faster pace due to the higher current.
Of course, this also shows the whole headache of using 12 VDC appliances like this, as you can only pull so much current from a cigarette lighter socket, while connecting directly to the battery and its juicy 100 A or more poses its own logistical problems. Taking the inverter losses as the price to pay for convenience is thus another totally valid option whenever you’re out camping or at that off-grid cabin.
2026-03-27 04:00:56
So-called bug out cars are a rather silly venture that serve little purpose more than snagging your jumper. The odds of a car working well through a nuclear winter are rather minimal. But what about a bicycle? On paper it’s a better choice, with extreme efficiency, reliability, and runs off whatever sustenance you can find in the barren landscape of a collapsed society. But [Seth] over at Berm Peak proved an apocalypse bike is at least as silly as a bug out car.
While a utilitarian bike fit for a cross-country trek across a nuclear wasteland can certainly be a reasonable venture, this particular bicycle is not that. This three wheeled monstrosity of a bicycle (is it still a bicycle if it has three wheels?) was built by [TOMO] for the Bespoked bike show’s apocalypse buildoff. It placed second among a number of strange bikes with features ranging from pedal driven circular saws to beer keg grills. But this particular example of apocalypse bike is easily the strangest example of the lot.
The features on this custom build are rather extensive, but the star of the show is the trailing link two wheel drive rear end. The third wheel was thrown on last minute with a random shock providing some measure of compliance to the rather unwieldy system. But while adding unnecessary complexity, the third wheel does offer the benefit of bringing along a number of spare parts on the last bikepacking trip of a lifetime. Moreover, it can be easily removed to get something resembling bicycle.
The aforementioned front of the bike while being an actual bike, is likewise a rather strange build. It’s best described as a fat-tired long nosed tall cargo bike. The removable cargo rack is quite effective in storing heavy loads by keeping the center of gravity near or below the axles, it can remain rideable with quite heavy loads. But, if ground clearance is needed, then simply remove the cargo rack, and the bike becomes a bike capable of navigating the nuclear wasteland it was made for.
While this is a silly and questionable bike, it’s certainly not the first strange bike we have seen.
2026-03-27 02:30:30
Pocket computers like Sharp’s 8-bit computing marvels were a big part of the 1980s, providing super-portable processing power to anyone who wanted a bit more than what something like a scientific calculator could provide at the time. These days they are mostly just a collector’s item for retrocomputing enthusiasts, which also means that a lot of the knowledge about how to program the CPUs in them is at risk of being lost.
This is why [gikonekos] decided to combine as much knowledge they can glean from official documentation into a reference project on GitHub for the SC62015 equipped Sharp pocket computers like the PC-E550.
Generally you’d program in Sharp’s dialect of BASIC on these computers, such as the ‘PLAY3’ program that [gikonekos] recently unearthed from a November 1993 copy of ‘Pocket Computer Journal’ using which you can create polyphonic tunes. This only unlocks a small part of what the hardware can do, of course, so having a full opcode reference like this is important.
While still a work in progress, it’ll eventually contain the full opcode and register tables, addressing modes, instruction summaries and of course a full accounting of how all of this was reconstructed. As the original Sharp documentation wasn’t released to the public, providing these scans is also not a goal, especially not under any kind of free license.
A cursory search reveals an instruction table for the PC-E500 from 1995 by [Andrew Woods], so documenting this is not a new thing, although at the time these Sharp pocket PCs didn’t count as ‘retro systems’ yet.
