Flying An RC Airplane With Twin Airblower EDFs

November 2, 2026 by Maya Posch 14 Comments

Shortly after [RCMakerLab] posted his question on potentially equipping an RC airplane with the electronic ducted fans (EDFs) from those airblower devices – are sold mostly as a replacement for canned air – the comment sections pretty much exploded with comments that he should just have strapped them onto an RC airplane and see for himself. In a new video this is exactly what is done, creating a somewhat A-10 Warthog-esque RC plane with its twin EDF turbines.

After we first covered this journey, the next question that got answered in the subsequent video was whether replacing the default electronic speed control (ESC) would make sense, mostly to lighten the load and optimize it for use with a typical RC avionics controller. This turned out to be the case, and thus it’s time for a test flight.

The aircraft created from largely styrofoam board seems to be largely designed for stability, with its large wings and the very A-10-like placement of the turbines right above the tail with its twin vertical stabilizers. It wasn’t really a shocker to see that the resulting 368 gram light airplane actually flies pretty well, with it taking off almost immediately.

With the used 2S1P, 1300 mAh Li-Po battery total flight time is about 3-4 minutes, which seems about on par with typical numbers. With a larger airplane and battery these two EDFs probably could be pushed even further, which we fully expect to see in a future video.

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Investigating Whether Zener Diodes Work For ESD Protection

November 2, 2026 by Maya Posch 13 Comments

Sometimes the naming of parts in electronics can contribute to confusion about what they are good for, with the topic of Zener diodes in the context of fast surges like those from electrostatic discharge (ESD) being a good example. In a recent video by [BTT Lab] this particular question regarding Zener suitability for suppressing ESD is addressed, as compared to transient-voltage-suppression (TVS) diodes.

The main argument against using Zener diodes for ESD and similar surge suppression is that they react too slowly, which obviously gives said surge time to cause some real damage. This is where a special form of avalanche effect-based diodes called TVS diodes are recommended, as their response time is in the picoseconds rather than nanoseconds or slower as for Zener diodes.

Although this is technically true, as also pointed out in the video, a Zener diode also uses the avalanche effect, with the diode starting off conducting in the reverse direction using the Zener effect before transitioning to the much faster avalanche effect. The transition point is hereby determined by how heavily the p-n junction is doped, making effectively all Zener diodes also avalanche diodes.

TVS diodes consequently are basically Zener diodes that are optimized for a very early transition to said avalanche effect. They are also generally larger than typical Zener diodes as they generate a lot of internal thermal energy while in reverse conducting mode, which has to be contained and shed without causing permanent damage.

The short version is thus that diodes marked as ‘TVS’ are the best choice for surge protection, while those marked as ‘Zener’ are best used for voltage clamping, reference voltages and all other typical Zener diode things.

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Solar Light Shows Why Replacing NiMH With Li-Ion Is Dangerous

November 2, 2026 by Maya Posch 49 Comments

Recently [DiodeGoneWild] got his paws on a purportedly IP44-rated outdoor solar light with PIR motion sensor that also contains an 18650 Li-ion cell. Since it’s being sold in Czechia in a supermarket by a Czech company you’d expect it to meet at least some quality standards, but once he got inside the device a true horror show unfolded.

The best guess here is that someone took an originally cheap NiMH cell-based solar light circuit and simply replaced said NiMH cell with an – unprotected – Li-ion 18650 cell, as there is absolutely no charging management or cell protection. This is important as while NiMH will throttle charging current by rejecting it as heat the more it is in a charged state, Li-ion is not as tolerant.

Even ignoring that the ‘IP44’ enclosure has more gaps and holes in it than the average slice of Swiss cheese, the 5.5 V-rated PV solar panel happily tried charging the Li-ion cell at around 6 V. This raises the potential that on a particularly sunny day with an already charged Li-ion cell sitting at 4.2+ V, it’ll effectively grenade this cell.

During an outdoors test the 18650 cell was charged to 4.8 V before the sun vanished behind the building, which probably isn’t an amazing sign if you are expecting for this light to keep working for more than a few weeks. Or not violently explode/catch on fire on the side of your house for that matter.

Of course, treating a NiMH cell better than in this particular circuit will extend its lifespan as well, but the failure mode of that battery chemistry tends to be a bit less aggressive. Hence why people keep getting away with dodgy circuit designs like this.

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Turning Syngas Into Hydrocarbons With The Right Alpha

November 1, 2026 by Maya Posch 12 Comments

Although the Fischer-Tropsch synthesis (F-T synthesis) process is well-known and on face value quite straightforward, using it for DIY production of a somewhat defined length hydrocarbons is fairly tricky. This is the topic of a recent video by [Hyperspace Pirate], in which he goes over getting the right alpha value for his FT reactor in order to not just create the equivalent of crude oil.

This alpha value is determined by the temperature and pressure inside the reactor as the syngas – consisting of carbon monoxide and hydrogen – is encouraged by the catalyst material to turn into proper carbohydrates. At very low alpha values this process will finish very quickly, creating mostly methane (CH₄), while a higher number creates increasingly longer carbohydrate chains before they terminate with their final hydrogen molecules.

Since this process is exothermic, this creates many exciting opportunities for a production batch to be ruined unless you can somewhat control the temperature and pressure inside the reactor vessel. In the video a heater is used to kickstart the reaction, before it is turned off. As a catalyst an iron-based material is created that is packed inside the steel tube which forms the reactor vessel.

Through this the syngas is led, with the initial experiments producing a few mL of what appears to be pentane and hexane, with the rest apparently being gaseous methane, ethane and similar. This points to a fairly low alpha value, which is not ideal if your goal is to synthesize a specific hydrocarbon. With how complex this process is, there’s a good argument to be made that using F-T synthesis at a high alpha to churn out crude for standard distillation might be the easier method.

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Rooting An Amazon Echo Dot

October 31, 2026 by Maya Posch 12 Comments

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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Voyager 1 Briefly Goes Silent, Scaring Everyone

October 31, 2026 by Maya Posch 32 Comments

It’s no big secret at this point that we are looking at the final years of the two venerable Voyager spacecraft. With their power supplies diminishing and their 1970s-era electronics still giving it all they got, their teams are working miracles to stretch out the time to the final goodbye for as long as possible. Despite these efforts Voyager 1 went silent for more than 24 hours on October 18 and 19, with the team still trying to figure out what happened.

The most recent change to Voyager 1 was the same ‘big bang’ switching of multiple instruments to lower-power versions, while keeping an eye on keeping the electronics and fuel at reasonable temperatures. This should give both spacecraft a few more years before power reserves fall below usable levels. Whether this switch is related to this communication blackout is currently unknown.

From the diagnostic data that the team obtained after communications were restored it’s clear that a group of thrusters went offline with backup units kicking in, indicating that the onboard computer detected some kind anomaly with the former. Whether this is a recurrence of the clogged fuel lines that has been observed before will have to be investigated.

We still fervently hope that both Voyagers can make it into the 2030s before both of them will fall silent forever. Final goodbyes are never easy, but we are most grateful to the Voyager teams over the decades for going above and beyond to make sure that literally everything has been attempted before those fateful days arrive.

Thanks to [Mark Stevens] for the tip.

Making Internal Combustion Engines Better With More Valves

October 30, 2026 by Maya Posch 36 Comments

When it comes to internal combustion engines (ICEs), it’s generally accepted that each cylinder doesn’t have more valves to let in a fresh fuel mixture and to exhaust the aftermath than absolutely necessary. You could argue in favor of this also because it reduces the amount of valve seat surface and thus the potential for leaks, but there is historical precedent for higher valve counts. Hence [Alexander’s Laboratory] had to give a ten-valve engine a shake, just to see what effect adding more valves has.

A cited historical example is the Yamaha FX750, which features a four-cylinder engine that has three inlet and two outlet valves per cylinder, making for a 20-valve design that is claimed to improve performance, also because each valve can be smaller and lighter than with a single valve per side. Other motorbike manufacturers would also try such configurations, with some fascinating examples shown in the video.

What [Alexander] tries here is to create a 10-valve version, for a symmetric five valves intake and five for exhaust. Rather than building an entire engine from scratch, the largely 3D-printed ICE that was featured in previous videos will be modified with a new cylinder head, replacing the current four-valve one.

For the custom valves large wood screws are used, after making sure that they can take the heat of the combustion. Making even ten of these small valves fit was a challenge, but ultimately got squeezed into a CNCed aluminium and nylon-printed hybrid cylinder head. The existing camshaft was reused by using an adapter that simply drives five valves at the same time.

After some troubleshooting and tuning the engine actually runs pretty well, though sadly no comparison metrics were provided versus the four-valve version of the cylinder head. Hopefully we’ll see this in an upcoming video.

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