Radon Active

When you think about nuclear radiation, you often think about power plants, but it turns out there’s radioactive stuff all over the place: smoke detectors, granite counters, bananas, and potatoes can all be mildly radioactive. Even some old tape dispensers. But those are all puny sources.

Radon is a colorless, odorless gas that is heavier than air. It is a byproduct of uranium decay, amonth other pathways, decays by emitting an alpha particle, and has a half-life of just about four days. As a gas, it escapes from rocks or soil. Usually, there isn’t much of it, so it vents harmlessly to the atmosphere. But it can easily get trapped in a house and accumulate. You might think your house is solid, but there are plenty of cracks, joints, and pipes where gas can weasel through, especially if your inside pressure is slightly lower than the pressure in the soil below, which is common.

As the radon decays, it can produce more radioactive material, including tiny amounts of polonium. With or without dust particles, these tiny bits of radioactive material can go airborne and end up in your lungs. There, they can further decay, and alpha particles damage cells and DNA. According to the EPA, radon exposure is the second leading cause of lung cancer in the United States, next to smoking.

Not So Speedy

If you get enough carbon monoxide in your home, you probably won’t see the next sunrise. But radon works very slowly. It is odorless and colorless. You won’t show any general symptoms to warn you that you might get lung cancer.

The effect can take years or decades. Of course, you can also have a house that has very little radon. However, nearly all homes have some radon. The EPA estimates that about 7% of homes have elevated radon levels.

Some areas are more prone to radon than others, but even if your area has low risk, there’s no guarantee that your house is safe. If you are lucky enough to not have a radon problem, you have nothing to worry about. But how do you know? Like anything, you need to test.

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Making A Dog Car Wash Without (very) Fancy Tools

[Stuff Made Here] got fed up with the hassle of washing their dog, and in traditional engineer fashion, decided that automating the process would solve the problem. However, as science fiction writers love to warn us, automation and living things don’t always mix.

The concept, much like a car wash, is to have an arch-like structure spray the dog with oscillating nozzles. A secondary nozzle provides a simple air drying function on each of the pods. An “undercarriage” nozzle of similar design runs in a channel below the dog to ensure all mud has been removed. The nozzles move along linear rails, driven by a DC motor. All the electronics are water proofed with the AC power source a distance away to provide additional electrical protection.

Unlike other projects of the past, [Stuff Made Here] set out to make this project without fancy metal working tools. Fortunately, it’s a project well suited to SLA 3D printing. While probably printable on an FDM printer, the parts need to withstand water back pressure. While there are better ways of doing this, the nozzles are mounted on an arch made of two bent conduits with legs welded on. The nozzles are mechanically connected with linkages to control the spraying direction.

However, [Stuff Made Here] couldn’t resist the urge to use a new CNC lathe when it arrived, so the quest to avoid fancy tools was lost to the desire to play with new fancy tools. Also, a grate under the under-carriage nozzle would have taken too long to source, so instead a plasma cutter made short work of some sheet metal. Granted, the parts could easily be 3D printed and/or sourced online.

Besides the fact that the dog is terrified of the machine and won’t use it, it works brilliantly! Sound off in the comments if you think [Stuff Made Here]’s attempt at making a project without fancy tools was successful.

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Cat Feeder Ensures Fed Cats

Automatic cat feeders are a dime a dozen, largely because this is an easy problem to solve. Dry cat food is easy for machines to manipulate, and the electronics needed to accomplish the task to a bare minimum are plentiful and inexpensive. But just doling out food is only easy part of the problem. [Jason] wanted to make sure that his cats actually ate once the food was dispensed so he added a few extra features to this cat feeder.

The main addition to this feeder compared to off-the-shelf models is a weight sensor under the bowl. The feeder metes out a certain amount of food, and then a Raspberry Pi Pico W keeps an eye on the weight of the dish. If it goes down, presumably the cat has eaten all of the food. But just to be sure, an ultrasonic sensor was added beside the bowl to ensure something cat-shaped was there at the same time. There was some issue with this sensor blasting out noise in a cat’s audible range at first, but it seems like that problem has since been solved as well.

The build has a few other perks as well. The hardware has wireless communication ability, so it’s easy to keep an eye on when out and about. It can log data and is much more programmable than others. Like most cat feeders, though, it’ll only work for dry food. For automatically feeding wet food something like this robotic feeder that opens cans and dispenses them at set intervals would be needed.

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Rooting An Amazon Echo Dot

The Amazon Echo Dot is one of Amazon’s so-called ‘smart speaker’ offerings that tie into their larger Alexa-fueled ecosystem, designed to be a pretty minimalistic device that gives you access to this voice assistant and also the Amazon AWS cloud access to your home. If that latter part isn’t really your jam, you can always try to unshackle the device from the Amazonian cloud by rooting the device, as [Andy] recently did with a 2018 Echo Dot 3.

In addition to the video there is also a blog post in which the steps required to root the device are covered. This is then used to turn the device into a Home Assistant voice satellite, using a Claude-vibecoded project created by [Julian Imhof]. As [Andy] notes, this code seems to work, but it’s completely unaudited so YMMV. Device support is also limited to only certain Echo Dot and Echo Show devices as listed on the project page.

The first step is to gain USB access to the board inside the device, which for USB-less devices like the Dot in question requires opening the device to solder a USB connector onto the test pads that are available on the PCB. For other Echo devices you can just use the existing USB port, which makes this first step slightly easier.

These devices run Fire OS, so basically Android, which means a fairly standard process of unlocking the bootloader and installing the hassmic application that replaces Alexa. During testing [Andy] noticed that voice processing was rather slow, requiring switching from Whisper to Speech-to-Phrase to make simple things like turning a light on not take a minute.

Overall it seems like a pretty decent way to repurpose these devices as ESPHome devices, with a few gotchas when it comes to the resources required for local voice processing.

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Running DOOM (Sort Of) On A Sonoff Smart Switch

It’s often said in this community that DOOM can be made to run on anything, and as time goes on, that’s becoming more and more accurate. We’re at the point now that every “normal” device seems to have some version of the iconic 1993 shooter, so now there’s nothing left but to start working on the more oddball targets.

As a perfect example, [piuppi] recently wrote in to share their efforts to get DOOM — or at least something that looks like it — running on the Sonoff Basic R2 smart switch. We say something that looks like it because the game you’re seeing in the video below isn’t actually DOOM. In fact, it’s not even really a full game. It’s essentially a tech demo that’s capable of rendering graphical data pulled from the game, but only within the confines of simplistic map. Still, not bad for something designed to turn lamps on and off.

The GitHub repo includes excellent documentation should you want to rip and tear on your own Sonoff device. As you might expect the process is a bit involved, and does require you to provide your own copy of DOOM for the script to extract the necessary data from. After it’s setup, you can hit the switch from any browser on the local network and take out your frustrations on the state of modern home automation on some imps. The best part is, even after the game is installed and running on the switch, the device still actually works as a switch.

But don’t worry. Even in the unlikely event that we run out of devices that can be hacked to run DOOM, there’s still a whole world of gadgets out there that need their own port of Duke Nukem 3D.

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Elgato Key Lights Get Matter Upgrade

[Michael H Thiesen] had a couple of Elgato Key Lights in his home streaming setup. The only problem was that they would stop responding regularly, requiring a power cycle to get them going again. He never quite pinned down where the problem lay; instead, he set about replacing the light controllers wholesale to provide more reliable functionality.

In place of the original controllers, a pair of ESP32-C3 boards were substituted in. The original design simply had a Realtek controller chip wired into a PCA9635 LED controller, so the swap was as easy as plucking one out and wiring the new microcontroller in its place. The capable ESP32-C3 offers native Matter support, which enabled the new controllers to join [Michael’s] Apple Home setup natively. Running a firmware coded in Rust, the controllers offer power, brightness, and colour-temperature control right in Apple Home. As a bonus, there was no need to use Homebridge to get the lights hooked up to the smarthome setup anymore, eliminating a dependency and a possible source of occasional failures.

Design files are on Github for the curious. We’ve featured other great Elgato hacks before, too, like this nifty capture card firmware hack. If you’re tinkering with your own smarthome hacks, be sure to let us know on the tipsline.

Dumpster-dived Window A/C Becomes Ground-Source Heat Pump

Heat pumps are great, because they pump heat around, and we often don’t want heat where it is. Need it somewhere else? Pump it! It’s great. It’s also a bit pricey if you’re buying new, but [Craftsman Chris] over on YouTube realized that the window air conditioning unit he found in a dumpster is, in fact, a heat pump. Normally it’s an air-source heat pump, but with a delightful series of hacks, he gets it automated and hooked into a ground loop in his latest YouTube video.

The heat sink is provided by a bunch of PEX tubing [Chris] buried in his back yard. After experimenting with using the water loop for cooling directly, he realized that pumping heat out of his house into the cold ground would go much better with a heat pump. That’s where the window A/C came in. After cleaning and servicing it, it was time to convert it to dump heat into water rather than outside air. To do that, [Chris] welded up a tank made of scrap metal around the existing heat exchanger. It’s designed for air, sure, but water takes its heat just fine. The nice thing about this is that by keeping the internals of the air conditioner mostly stock, he doesn’t let out any of the tasty, tasty CFCs that may be hiding inside.

Connecting this unit to his thermostat is equally hacky– he takes an old Programmable Logic Controller that looks fit to run a small factory, and hooks it to a single linear actuator to poke the A/C unit’s stock power button. Is it elegant? No. Does it work? Yes. Is it a hack? Indubitably!

We’ve seen window units pressed into whole-house A/C service before, but adding the water loop is a great hack. We saw a window A/C used as a ground-source pump before, too, but that was a Canadian project and so sensibly turned the machine around to provide heating for the maple mansion.

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