Author: Lewin Day

2967 Articles

ESP32 Powers DIY Smart Energy Meter

December 2, 2024 by 18 Comments

Energy is expensive these days. There’s no getting around it. If, like [Giovanni], you want to keep better track of your usage, you might find value in his DIY energy meter build.

[Giovanni] built his energy meter to monitor energy usage in his whole home. An ESP32 serves as the heart of this build. It’s hooked up with a JSY-MK-194G energy metering module, which uses a current clamp and transformer in order to accurately monitor the amount of energy passing through the mains connection to his home. With this setup, it’s possible to track voltage, current, frequency, and power factor, so you can really nerd out over the electrical specifics of what’s going on. Results are then shared with Home Assistant via the ESPHome plugin and the ESP32’s WiFi connection. This allows [Giovanni] to see plots of live and historical data from the power meter via his smartphone.

A project like this one is a great way to explore saving energy, particularly if you live somewhere without a smart meter or any other sort of accessible usage tracking. We’ve featured some of [Giovanni]’s neat projects before, too.
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Saving A Samsung TV From The Dreaded Boot Loop

November 30, 2024 by 37 Comments

[eigma] had a difficult problem. After pulling a TV out of the trash and bringing it home, it turned out it was suffering from a troubling boot loop issue that basically made it useless. As so many of us do, they decided to fix it…which ended up being a far bigger task than initially expected.

The TV in question was a Samsung UN40H5003AF. Powering it up would net a red standby light which would stay on for about eight seconds. Then it would flicker off, come back on, and repeat the cycle. So far, so bad. Investigation began with the usual—checking the power supplies and investigating the basics. No easy wins were found. A debug UART provided precious little information, and schematics proved hard to come by.

Eventually, though, investigation dialed in on a 4 MB SPI flash chip on the board. Dumping the chip revealed the firmware onboard was damaged and corrupt. Upon further tinkering, [eigma] figured that most of the dump looked valid. On a hunch, suspecting that maybe just a single bit was wrong, they came up with a crazy plan: use a script to brute-force flipping every single bit until the firmware’s CRC check came back valid. It took eighteen hours, but the script found a valid solution. Lo and behold, burning the fixed firmware to the TV brought it back to life.

It feels weird for a single bit flip to kill an entire TV, but this kind of failure isn’t unheard of. We’ve seen other dedicated hackers perform similar restorations previously. If you’re out there valiantly rescuing e-waste with these techniques, do tell us your story, won’t you?

Building A Miniature Rainbow Sand Table

November 30, 2024 by 8 Comments

Sure is coarse and rough and irritating, and it gets everywhere. But it can also be beautiful — drag a small ball through it in a controlled manner you can make some really pretty patterns. That’s precisely what this compact build from [Printerforge] does.

The build relies on an ESP32 as the brains of the operation. It employs small 28BYJ-48 motors to run the motion platform. These were chosen as they operate on 5 V, simplifying the build by allowing everything to run off a single power supply. Along with a bunch of 3D printed parts, the motors are assembled into motion system with linear rods and belts in a CoreXY layout, chosen for speed and precision. It’s charged with moving a small magnet to drag a ball bearing through the sand to draw patterns under the command of G-code generated with the Sandify tool.

We’ve seen some great sand table builds over the years. Some use polar coordinate systems, while others repurpose bits of 3D printers. If you’ve got a creative new way of doing it, don’t hesitate to let us know!

Simple Pen Plotter Rolls On The Table

November 29, 2024 by 6 Comments

Pen plotters are popular builds amongst DIY CNC enthusiasts. They’re a great way to learn the fundamentals of motion control and make something useful along the way. In that vein, [Maker101] has created a neat barebones plotter for tabletop use. 

The basic design relies on familiar components. It uses a pair of MGN15 linear rails as the basis of the motion platform, along with NEMA 17 stepper motors to run the X and Y axes. These are assembled with the aid of 3D-printed parts that bring the whole frame together, along with a pen lifter operated with a hobby servo.

The neat thing about the design is that the barebones machine is designed to sit upon an existing tabletop. This eliminates the need to integrate a large flat work surface into the plotter itself. Instead, the X axis just runs along whatever surface you place it on, rolling on a small wheel. It’s likely not ideal for accuracy or performance; we could see the machine itself skating around if run too fast. For a lightweight barebones plotter, though, it works well enough.

If you dig building plotters, you might like to step up to something more laser-y in future. Video after the break.

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Building A Generator That Runs Off Hose Power

November 29, 2024 by 66 Comments

[Paul Junkin] bought a curious product off the Internet. It was supposed to generate electricity when hooked up to a running hose. Only, it didn’t do a very good job. His solution was straightforward—he built his own hose-powered generator that actually worked.

The design uses a turbine hooked up to a small motor acting as a generator. To maximize the transfer of energy from the stream of water to the blades of the turbine, the hose is hooked up to a convergent nozzle. [Paul] does a great job explaining the simple physics at play, as well as the iterative design process he used to get to the final product. He calculates the best-case power coming out of his hose around 50 watts, so for his turbine to collect 22 watts is a win, and it’s good enough to charge a phone or run some LED lighting.

Of course, this isn’t a practical generator if you have to pay for the water, and there are other solutions that will get you less wet. Still, credit where it’s due—this thing does make power when you hook it up to a hose. We’ve seen some slightly less ridiculous concepts in this space before, though.

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Low-Profile Travel Keyboard Is Mostly 3D Printed

November 29, 2024 by 9 Comments

If you’ve got a nice mechanical keyboard, typing on anything else can often become an unpleasant experience. Unfortunately, full-sized versions are bulky and not ideal when you’re travelling or for certain portable applications. [Applepie1928] decided to create a small travel keyboard to solve these problems.

Meet the Micro Planck. It’s a simple ortholinear mechanical keyboard in a decidedly compact form factor—measuring just 23 cm wide, 9.5 cm tall, and 2 cm deep. You could probably stuff it in your pocket if you wear baggy jeans. Oh, and if you don’t know what ortholinear means, it just means that the keys are in a straight grid instead of staggered. Kind of like those “keyboards” at the bowling alley.

The build relies on Gateron KS-33 switches installed on a custom PCB, with a ATmega32U4 microcontroller running the popular open source QMK firmware. The keyboard has a USB-C port because it’s 2024, and all the components are wrapped up in a neat 3D printed shell.

Overall, it’s a tasteful design that packs in a lot of functionality. It’s also neat to see a mechanical design used which offers more tactile feedback than the rubber dome designs more typical at this scale. Meanwhile, if you’re cooking up your own nifty keyboard designs, don’t hesitate to let us know what you’re up to!

Ultra-Wide Gaming Handheld Channels The Nintendo DS

November 28, 2024 by 16 Comments

“The Nintendo DS isn’t wide enough!” said nobody, ever. Most players found Nintendo’s form factor to be perfectly acceptable for gaming on the go, after all. Still, that doesn’t mean a handheld gaming rig with a more… cinematic aspect ratio couldn’t be fun! [Marcin Plaza] built just that, with great results.

The initial plan was to build a Steam Deck-like device, but using laptop trackpads instead of joysticks. [Marcin] had a broken Lenovo Yoga 730-13 to use as the basis for the build. That caused the plan to diverge, as the only screen [Marcin] could find that was easily compatible with the laptop’s eDP interface was an ultrawide unit. From there, a clamshell enclosure was designed specifically to rehouse all the key components from the Lenovo laptop. The top half of the clamshell would hold the screen, while the base would feature a small custom keyboard, some buttons, and the aforementioned trackpad. This thing reminds us of the Nintendo DS for multiple reasons. It’s not just the clamshell design—it’s the fact it has a touch control on the lower deck, albeit without a screen.

It’s an original concept for a handheld gaming device, and it makes us wish there were more games built for the ultrawide aspect ratio. This is one project that has us browsing the usual websites to see just what other oddball screens are out there… round screens in a makeup compact clamshell, anyone? Video after the break.

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