Condensing Diesel Heater Hack Is Dripping With Efficiency

December 13, 2025 by Tyler August 7 Comments

Not a huge percentage of our readers probably get their heat from diesel fuel, but it’s not uncommon in remote areas where other fuels are hard to come-by. If you’re in one of those areas, this latest hack from [Hangin with the Hursts] could save you some change, or keep you ̶2̶0̶%̶ ̶c̶o̶o̶l̶e̶r̶ 25% warmer on the same fuel burn.

It’s bog simple: he takes his off-the-shelf hydronic diesel heater, which is already 71% efficient according to a previous test, and hooks its exhaust to a heat exchanger. Now, you don’t want to restrict the exhaust on one of these units, as that can mess with the air fuel mix, but [Hurst] gets around that with a 3″ intercooler meant for automotive intake. Sure, it’s not made for exhaust gas, but this is a clean-burning heater, and it wouldn’t be a hack if some of the parts weren’t out of spec.

Since it’s a hydronic heater, he’s able to use the exhaust gas to pre-heat the water going into the burner. The intercooler does a very good job of that, sucking enough heat out of the exhaust to turn this into a condensing furnace. That’s great for efficiency — he calculates 95%, a number so good he doesn’t trust it — but not so good for the longevity of the system, since this intercooler isn’t made to deal with the slightly-acidic condensation. The efficiency numbers are combustion efficiency, to be clear. He’s only accounting for the energy in the diesel fuel, not the energy that heats the water in his test, for the record; the electrical power going into the blower is considered free. That’s fair, since that’s how the numbers are calculated in the heating industry in general — the natural gas furnace keeping this author from freezing to death, for example, is a condensing unit that is also 95% efficient.

Another thing you can do to get the most from your diesel heating fuel is add some brains to the operation. Since this is a hydronic system, the cheapest option, long-term, might be to add some solar energy to the water. Sunlight is free, and diesel sure isn’t getting any cheaper.

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Get Statistical About Your Pet With This Cat Tracking Dashboard

December 13, 2025 by Lewin Day 3 Comments

Cats can be wonderful companions, but they can also be aloof and boring to hang out with. If you want to get a little more out of the relationship, consider obsessively tracking your cat’s basic statistics with this display from [Matthew Sylvester].

The build is based around the Seeedstudio ReTerminal E1001/E1002 devices—basically an e-paper display with a programmable ESP32-S3 built right in. It’s upon this display that you will see all kinds of feline statistics being logged and graphed. The data itself comes from smart litterboxes, with [Matthew] figuring out how to grab data on weight and litterbox usage via APIs. In particular, he’s got the system working with PetKit gear as well as the Whisker Litter Robot 4. His dashboard can separately track data for four cats and merely needs the right account details to start pulling in data from the relevant cat cloud service.

For [Matthew], the build wasn’t just a bit of fun—it also proved very useful. When one of his cats had a medical issue recently, he was quickly able to pick up that something was wrong and seek the help required. That’s a pretty great result for any homebrew project. It’s unrelated, too, but Gnocci is a great name for a cat, so hats off for that one.

We’ve featured some other fun cat-tracking projects over the years, too. If you’re whipping up your own neat hardware to commune with, entertain, or otherwise interact with your cat, don’t hesitate to let us know on the tipsline.

User Serviceable Parts

December 13, 2025 by Elliot Williams 14 Comments

Al and I were talking on the podcast about the Home Assistant home automation hub software. In particular, about how devilishly well designed it is for extensibility. It’s designed to be added on to, and that makes all of the difference.
That doesn’t mean that it’s trivial to add your own wacky control or sensor elements to the system, but that it’s relatively straightforward, and that it accommodates you. If your use case isn’t already covered, there is probably good documentation available to help guide you in the right direction, and that’s all a hacker really needs. As evidence for why you might care, take the RTL-HAOS project that we covered this week, which adds nearly arbitrary software-defined radio functionality to your setup.

And contrast this with many commercial systems that are hard to hack on because they are instead focused on making sure that the least-common-denominator user is able to get stuff working without even reading a single page of documentation. They are so focused on making everything that’s in-scope easy that they spend no thought on expansion, or worse they actively prevent it.

Of course, it’s not trivial to make a system that’s both extremely flexible and relatively easy to use. We all know examples where the configuration of even the most basic cases is a nightmare simply because the designer wanted to accommodate everything. Somehow, Home Assistant has managed to walk the fine line in the middle, where it’s easy enough to use that you don’t have to be a wizard, but that you can make it do what you want if you are, and hence it got spontaneous hat-tips from both Al and myself. Food for thought if you’re working on a complex system that’s aimed at the DIY / hacker crowd.

A biohacker with her lactose-rich slurry

Biohack Your Way To Lactose Tolerance (Through Suffering)

December 13, 2025 by Tyler August 33 Comments

A significant fraction of people can’t handle lactose, like [HGModernism]. Rather than accept a cruel, ice cream free existence, she decided to do something you really shouldn’t try: biohacking her way to lactose tolerance.

The hack is very simple, and based on a peer reviewed study from the 1990s: consume lactose constantly, and suffer constantly, until… well, you can tolerate lactose. If you’re lactose intolerant, you’re probably horrified at the implications of the words “suffer constantly” in a way that those milk-digesting-weirdos could never understand. They probably think it is hyperbole; it is not. On the plus side, [HGModernism]’s symptoms began to decline after only one week.

The study dates back to the 1980s, and discusses a curious phenomenon where American powdered milk was cluelessly distributed during an African famine. Initially that did more harm than good, but after a few weeks mainlining the white stuff, the lactose-intolerant Africans stopped bellyaching about their bellyaches.

Humans all start out with a working lactase gene for the sake of breastfeeding, but in most it turns off naturally in childhood. It’s speculated that rather than some epigenetic change turning the gene for lactose tolerance back on — which probably is not possible outside actual genetic engineering — the gut biome of the affected individuals shifted to digest lactose painlessly on behalf of the human hosts. [HGModernism] found this worked but it took two weeks of chugging a slurry of powdered milk and electrolyte, formulated to avoid dehydration due to the obvious source of fluid loss. After the two weeks, lactose tolerance was achieved.

Should you try this? Almost certainly not. [HGModernism] doesn’t recommend it, and neither do we. Still, we respect the heck out any human willing to hack the way out of the limitations of their own genetics. Speaking of, at least one hacker did try genetically engineering themselves to skip the suffering involved in this process. Gene hacking isn’t just for ice-cream sundaes; when applied by real medical professionals, it can save lives.

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PJON, Open Single-Wire Bus Protocol, Goes Verilog

December 13, 2025 by Arya Voronova 7 Comments

Did OneWire of DS18B20 sensor fame ever fascinate you in its single-data-line simplicity? If so, then you’ll like PJON (Padded Jittering Operative Network) – a single-wire-compatible protocol for up to 255 devices. One disadvantage is that you need to check up on the bus pretty often, trading hardware complexity for software complexity. Now, this is no longer something for the gate wielders of us to worry about – [Giovanni] tells us that there’s a hardware implementation of PJDL (Padded Jittering Data Link), a PJON-based bus.

This implementation is written in Verilog, and allows you to offload a lot of your low-level PJDL tasks, essentially, giving you a PJDL peripheral for all your inter-processor communication needs. Oh, and as [Giovanni] says, this module has recently been taped out as part of the CROC chip project, an educational SoC project. What’s not to love?

PJON is a fun protocol, soon to be a decade old. We’ve previously covered [Giovanni] use PJON to establish a data link through a pair of LEDs, and it’s nice to see this nifty small-footprint protocol gain that much more of a foothold, now, in our hardware-level projects.

We thank [Giovanni Blu Mitolo] for sharing this with us!

The Near Space Adventures Of Bradfield The Bear

December 12, 2025 by Al Williams 2 Comments

Admit it or not, you probably have a teddy bear somewhere in your past that you were — or maybe are — fond of. Not to disparage your bear, but we think Bradfield might have had a bigger adventure than yours has. Bradfield was launched in November on a high-altitude balloon by Year 7 and 8 students at Walhampton School in the UK in connection with Southampton University. Dressed in a school uniform, he was supposed to ride to near space, but ran into some turbulence. The BBC reported that poor Bradfield couldn’t hold on any longer and fell from around 17 miles up. The poor bear looked fairly calm for being so high up.

A camera recorded the unfortunate stuffed animal’s plight. Apparently, a companion plushie, Bill the Badger (the Badger being the Southampton mascot), successfully completed the journey, returning to Earth with a parachute.

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Super-Sizing Insects And The Benefits Of Bones

December 12, 2025 by Maya Posch 20 Comments

One swol mealworm amidst its weaker brethren. (Credit: The Thought Emporium, YouTube)

Have you ever found yourself looking at the insects of the Paleozoic era, including the dragonfly Meganeuropsis permiana with its 71 cm wingspan and wondered what it would be like to have one as a pet? If so, you’re in luck because the mad lads over at [The Thought Emporium] have done a lot of the legwork already to grow your own raven-sized moths and more. As it turns out, all it takes is hijacking the chemical signals that control the development phases, to grow positively humongous mealworms and friends.

The growth process of the juveniles, such as mealworms – the larval form of the yellow mealworm beetle – goes through a number of molting stages (instars), with the insect juvenile hormone levels staying high until it is time for the final molt and transformation into a pupa from which the adult form emerges. The pyriproxyfen insecticide is a juvenile hormone analog that prevents this event. Although at high doses larvae perish, the video demonstrates that lower doses work to merely inhibit the final molt.

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