DIY Mini Fridge Is Pure Brilliance In Foam

There’s nothing more pleasing on a hot day than an ice-cold beverage. While the vast majority of us have a fridge in the kitchen, sometimes it’s desirable to have a further fridge in the lab, games room, or workshop. To that end, you may find value in this ultra-cheap, low-cost DIY fridge build from [Handy_Bear].

Like many tiny fridge builds, this design eschews complex gas-cycle refrigeration techniques for simple Peltier modules. These are devices that have one cold side and one hot side, because they move heat when electricity is applied. This build uses a Peltier module fitted with a fan to better shift away heat from the hot side, improving the module’s cooling ability.

The “fridge” itself is assembled out of thick XPS insulation foam. A hot wire cutter was used to cut several slabs which were then assembled using hot glue. The Peltier module is installed on the back, at the top of the fridge. Thus, air which is cooled in this area will then travel down through the rest of the fridge’s cavity. [Handy_Bear] also goes over how to produce a working hinge and a gasket for the door, which helps with ease-of-use and efficiency. As a nice touch, a set of 12V LED lights are also installed inside, which light when the door is open. Just like the real thing!

The final build is noisy, slow to cool down, and it uses 60 watts of power to cool down just two regulation-sized sodas. Notably, you could fit two standard NATO smoke grenades in the same space, as they’re almost-identically sized (ask us how we know). However, smoke grenades don’t usually need to be refrigerated.

None of that means it isn’t fun though! Plus, [Handy_Bear] notes that adding a second Peltier would greatly aid the fridge’s ability to quickly chill your grenades sodas. You might even like to explore the use of special fan designs to make the fridge even quieter! Video after the break.

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LED Filament Lamp Is Subtle, Warm, And Elegant

Hackers have loved LEDs from day one, back when they gave us little more than a dim spot of colored light in the darkness. These days, they’re big, bright, and beautiful, and can be used to create some exquisite lighting fixtures. This lamp build from [lonesoulsurfer] is a great example of that.

The build uses LED filaments, which have grown popular for the way they emulate old-fashioned Edison filament bulbs. The filaments consist of tiny LEDs all in a row, covered in flexible material to allow them to act like a filament. They’ll happily power up from just 3V, and deliver great brightness and lovely warm light.

[lonesoulsurfer] bent up an elegant oval-shaped frame for the lamp, using common brass tubing. In the middle of the are two lengths of white plastic tubing with the LEDs inside. The brass is painted black, with the LEDs providing two bright glowing lines on the arms of the oval. The base is then made out of wood and copper tubing, providing a pop of material contrast to the rest of the frame.

It’s an elegant build, and one you can readily recreate at home. If you do so with enough finesse, it will stunt on anything Ikea or (Australian) Kmart has put out in the last decade, in both material quality and uniqueness. We do love a good lamp build around these parts, after all. Video after the break.

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Stair Climbing Rover Gets Up With Rocker Bogies

Doctor Who eventually made light of the fact that the Daleks were critically impaired when it came to staircases. This rover from [WildWillyRobots] doesn’t share that issue, thanks to a smart suspension design.

The rover itself is built using 3D printed components for everything from the enclosure, to the suspension system, as well as the wheels themselves. It uses a rocker-bogie design, which NASA designed for Mars-bound rovers and we often see copied for terrestrial applications. Gear motors are used for their plentiful torque, and they are placed directly within the wheels. Servos allow the individual wheels to be steered, allowing the rover to crab sideways and perform zero-radius turns.

The rocker-bogie setup does a great job of keeping the rover’s wheels touching the ground, even over rough terrain. It readily tackles a random pile of bricks with ease, in a way that many four-wheeled designs would struggle to match. Given its trials on Mars, it’s easy to call the rocker-bogie setup a thoroughly-proven design.

We’ve featured plenty of other rocker-bogie builds in the past; many of them are 3D printed as well.

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A Call For Better Shower Temperature Controls

A good shower is a beautiful, rejuvenating experience. Contrarily, a shower that’s either too hot or too cold becomes a harrowing trial of endurance. [Ben Holmen] has been musing on the way we control temperature in our showers, and he has come to the conclusion that it’s not good enough. He’s done the math, quantified the problem, and is calling for better solutions for all.

[Ben]’s plot of shower temperature vs. mixer tap angle.
[Ben]’s complaint rests with the mixer taps that have become the norm in modern shower installations. These taps have a 180-degree range of motion. On one end, you get maximum cold water output, on the other, maximum hot water output. This is fine for a kitchen sink where we often want one extreme or the other, and exact temperature isn’t important. However, for a shower, it’s terrible.

By [Ben]’s measurements, just a 10-degree range on his own shower tap corresponds to comfortable, usable temperatures. That’s means just 5.6% of the control range is devoted to temperatures the user is likely to select. His argument goes that this is the opposite of how it should work, and that most of the tap’s range should be dedicated to comfortable temperatures.

Ideal water temperature curve, compared to standard tap.

This would allow much finer control of shower temperature in the actual useful range. It would allow us to make tweaks to our shower temperature without having to ever-so-delicately nudge the mixer tap. Extreme hot and extreme cold temperatures should still be available, but left at the utter extremes.

Sadly, [Ben] doesn’t work for Big Tap, so he can’t directly influence the product sold to the public. Instead, he’s calling for manufacturers to develop shower valves that prioritize the temperatures that humans desire most. Unfortunately, it’s not immediately clear how the mechanics of such a valve would work without adding considerable cost and complexity when compared to the traditional model.

What do you think? Are things fine the way they are, or does [Ben] have a point? Perhaps you’re a two-tap evangelist! In any case, we’d love to hear your comments below. Meanwhile, if you’re more worried about the water bill than the temperature, we can help you there as well!

Hack Lets Intel MacBook Run Without A Battery

A long time ago, a laptop was a basic thing, and you could pretty much run one just by hooking up a power supply to the battery contacts. A modern MacBook is altogether fussier. However, when [Christophe] was stuck in the midst of a 2020 lockdown with no parts available, he found a way to get his damaged MacBook up and running without a battery.

The problem was brought about by a failing battery in the MacBook Pro 13″ from mid-2018, which swelled up and deformed the laptop’s case. Parts were unavailable, and the MacBook wouldn’t run at full speed without a battery fitted. That’s because with no battery present, the MacBook would send a BD_PROCHOT signal to the Intel CPU, telling it to slow down due to overheating, even when the chip was cool.

To get around the problem, [Christophe] used a tool called CPUTune. It allows fiddling with the various CPU settings of a MacBook. He deactivated the BD_PROCHOT signal, and also the CPU’s Turbo Boost feature. This ended the worst of the thermal throttling, and enabled semi-normal use of the machine.

It’s unclear why Apple would throttle the CPU with the battery disconnected. [Christophe]’s workaround got him back up and working again in the midst of a difficult period, regardless. We’ve seen some other great Macbook hacks before too, like this amazing save from serious water damage!

Thanks to [donaldcuckman] for the tip!]

Giant 3D Printed Excavator Is Awesome, But Needs Work

Many of us adored big construction machinery as children. Once we got past the cute, tiny age, it became uncool to gasp with shock and awe at diggers and bulldozers for some reason . [Ivan Miranda] still digs the big rigs, though, and built himself a giant 3D printed excavator that looks like brilliant fun. 

Why did Lego never make MegaTechnic blocks? [Ivan] shows us the true potential of bigger building blocks.
The build relies on [Ivan]’s giant 3D-printed Lego-like assembly kit. It lets him simply bolt together a bunch of plastic girders to make the key parts of the excavator, including the base and the digger arm itself. The digger arm is controlled with linear actuators of [Ivan’s] own design, which uses servos and threaded rod to do the job. They’re not as cool as hydraulics or pneumatics, but they get the job done well. For propulsion, [Ivan] built a tracked drive system again using his unique Lego-like blocks. The tracks were tedious to assemble, but add a lot to the excavators Awesomeness Quotient (AQ).

The overall build is quite slow, and more than a little fragile. It’s not quite ready for hardcore digging tasks. In reality, it’s serving as a test bed for [Ivan]’s 3D-printed building blocks that get better every time we see them. Video after the break.

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ESP32 Web Updater Allows File System Management And OTA Updates

Earlier versions of the Arduino IDE made uploading files to an ESP32’s SPIFFS filesystem easy via the ESP32FS plugin. Sadly, that’s no longer possible under the rewritten Arduino 2.0 IDE. Thankfully, [myhomethings] has stepped up to solve the problem with a new tool that also adds some new functionality.

The tool in question is the ESP32 Web Updater and SPIFFS File Manager. It features a web interface courtesy of the ESPAsyncWebServer library. Simply dialing into the ESP32’s IP address will grant one access to the interface. Once connected files can be uploaded to the ESP32, or deleted at will. Text files can be created and populated through the interface as well, and the SPIFFS file system can also be formatted if required. Plus, as a bonus, the interface allows for handy over-the-air firmware updates. One need only export a compiled binary from the Arduino IDE, and then load the resulting *.bin file into the ESP32 via the web interface. It does come with the caveat that if new firmware is uploaded that doesn’t include the ESP32 Web Updater itself, there will be no way to do further firmware updates in this manner.

For those working on projects that may need regular file system management, the tool may be very useful. Alternatively, if you just need to do OTA updates on an ESP32, we recently featured a way of doing them through GitHub.