Reverse Engineering And Self-Hosting The OBI Smart Energy Tracker

July 7, 2026 by Maya Posch 4 Comments

Sold by German DIY store OBI, the OBI Energy Tracker is a €15 set of two devices, one of which you essentially stick on top of your existing electricity meter. This then allows for electricity usage to be measured and tracked, with the data sent to the second, gateway device. This latter cloud-bound device is linked to an OBI account via the heyOBI app. This correspondingly called for the gateway device to be reverse-engineered and freed from its cloud-based shackles, a task that [Aaron Christophel] happily took upon himself.

The whole process is also covered in two videos, with the first providing all the essentials on reprovisioning the original firmware for a local MQTT server in English, while the second, German-language video focuses on custom firmware for the ESP32-C3 inside of the gateway device.

Inside the reader device is a Cortex-M0+-based BAT32G135 MCU that communicates with the meter via its IR protocol. This is then communicated via 868 MHz LoRa to the gateway device that will be placed somewhere within Wi-Fi reach by the user. Inside this latter device is as mentioned the ESP32-C3, which by default runs firmware that communicates via secure MQTT with an AWS cloud instance for the typical cloud-based shenanigans.

The aforementioned reprovisioning option doesn’t require firmware flashing, just a handful of steps to follow. This involves fetching the 32-bit TEA key, generating your own PKI, running your own MQTTS-capable broker and having the provided Python script handle the rest from there.

Flashing custom firmware is the other option, with straightforward UART/JTAG reflashing sadly disabled by the manufacturer. With the effort required here you could perhaps argue that simply connecting the reader device to a custom gateway device might be a lot easier, especially if you already have a LoRa transceiver and associated hardware.

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When An Engineering Education Doesn’t Teach You How To Really Make Anything

July 7, 2026 by Jenny List 40 Comments

In the sweltering temperatures of an unusually hot European heatwave, I found myself having a chat with a friend of mine from my university days. After discussing the health of his cat who had solved the problem of a fur coat on a hot day by flattening himself out on the concrete floor in the coolest place in the house, we moved on to tech matters. We’ve known each other for not far short of four decades, so this is familiar territory for us. The problems that come with taking a prototype to manufacturing, a process which even the most seasoned of engineers can slip up on.

The Difference Between Making, And Making For Manufacture

If you’ve ever taken a project and replicated it, you will know the progression. If you’re making five or ten widgets, you can debug and rework as needed, tweak things, and get things going. If you’re making more then this, the process consumes a greater proportion of your time, until a point at which manufacture becomes impractical. Maybe that’s around fifty boards, sometimes more or less. Continue reading “When An Engineering Education Doesn’t Teach You How To Really Make Anything” →

SB Mini II Is A Homebrew Apple II Clone

July 7, 2026 by Tyler August 10 Comments

On the one hand, the original Apple II has been copied over and over again since at least the early 80s, so maybe this hack is old hat to the greybeards around here. On the other hand, this is the year 2026. When Apple released it back in 1977, who could have predicted people would still be building these things nearly five decades later?

In that sense, a homebrew Apple II in the current year is pretty remarkable. It’s a really well done project by [simonboak], nicely open sourced with a case to match, so is worth looking at on its own merits.

It doesn’t run *DOOM*, but neither did the original. *Oregon Trail* is more this unit’s speed.

Unlike the later models, the original Apple II only used commercially available ICs, making it an easy target for recreation. No FPGAs required, just good old-fashioned DIPs. OK, these are modern CMOS versions of the chips, but other than that, the biggest concession to modernity is space on the board for a Raspberry Pi Pico to allow for connecting a USB keyboard.

The accompanying blog post lists some other differences from 1977’s favorite home computer: SRAM vs DRAM — because you know the Woz would have used it if he could — and omitting the composite video circuitry in favor a late-model VGA card. There’s no need for the composite output since he’s eschewing the period-appropriate CRT for a retro-styled LCD monitor, which is also 3D printed and available on Printables. It’s crazy to think that the Apple II family lived long enough not only to see the dawn of VGA but also well into its sunset.

If a homebuilt Apple ][ doesn’t impress, what about a PC-compatible circa 1995?

Is Now The Time For Volumetric 3D Printing?

July 7, 2026 by Ian Bos 15 Comments

Of all innovations adopted by the maker community within the past couple of decades, one stands among the rest on top for anything regarding manufacturing. It goes without saying here at Hackaday how many projects have been reliant on using the technology to turn their ideas into reality. 3D printing has been a maker community invention and, in return, has expanded this hacky community into something that anyone with an imagination can get into. It also goes without saying that the layer-based tech imposes limits on what we can actually create: think overhangs and layer adhesion. However, there’s a possibility that a recent offshoot of this scrappy community has the power to eliminate some of these faults.

Volumetric additive manufacturing (VAM) is a young technology that has a similar start to many new tech toys, including the original SLA of the first 3D printers. That is expensive and completely stuck in the laboratory… Fortunately, that’s not where 3D printing as a whole stayed, as the RepRap project managed to bring the obscure technology to the hobbyists’ main stage. An entire group of people formed and spent countless hours until the useless pieces of poorly extruded plastic could form parts impossible to make with anything else. A cool quirk of history is that it likes to repeat: examples spur recreation, and this appears to be happening with the technology found within VAM printing.

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An Interactive Tomato Farm Overseen By AI

July 7, 2026 by Ian Bos 11 Comments

Oh, the farming lifestyle…living off the land, fending for yourself. But who’s got time for all that? For the modern hacker, the best option in the garden space may be this over-engineered automated AI tomato farm created by [Gerd Nicolay]. You can even interact with it right now through the magic of the Internet.

[Gerd] started off with your run-of-the-mill pot and plant, choosing the humble tomato to keep the system simple. Then things started to escalate, with the addition of automatic lighting, watering, and data logging environmental parameters like humidity. Now we’re getting somewhere, but there’s more that can be added. How about an entire AI council to monitor and decide the fate of each individual tomato while recording an entire storyline to go alongside the growing cycle?

That’s right, four different models collaborate to ensure only the utmost quality of care for these tomatoes based on camera feeds, humidity, and various other environmental factors being recorded constantly. Is this a little overkill? Maybe for those who have even a modest sense of gardening knowledge — but who can bash the mountain of documentation and data collection on these wonderful little plants?

Perhaps the best part: you can recommend actions for the AI counsel to take from the comfort of your own web browser. While the TomatoFarm might be slightly unnecessary for the average farmer, if you want to try a more reasonable monitoring system, we have you covered too!

Why The NES Put Out A Wobbly Picture

July 7, 2026 by Jenny List 8 Comments

The NTSC television standard is a masterpiece of mid-century engineering, to pack a color image into the transmission bandwidth of a monochrome one, and to do so while maintaining backward compatibility with earlier monochrome TV sets. In terms of its timings and choice of sync and carrier frequencies it’s elegantly thought out for maximum quality on a 1950s round-CRT color TV set.

The trouble is, that while the standards are exacting, the receivers are quite forgiving, and will display adequately even with substantially off-spec video. [Nicole Express] is here with an in-depth examination of a time when that was pushed just a little bit too far, explaining why the Nintendo Entertainment System (NES) displayed wobbly color images.

We’re treated to a run-through of the NTSC standard itself, and a look at how some of the other consoles and home computers of that era either had similar problems, or managed to avoid them. The key lies in the exacting timing required to achieve perfect interlacing, and the NES’s use of a single crystal to provide all the clocks. The dot clock on adjacent frames was almost right, but not quite, leading to a side-to-side wobble that while barely perceptible, was exacerbated by some graphics. It’s a fascinating read.

We’ve looked at composite video in detail in the past.

NES image: JCD1981NL, CC BY 3.0.

Belt Fed Potato Cannon Spits Spuds

July 6, 2026 by Tyler August 23 Comments

Spud guns are a staple of summertime fun for the maker set, especially on the Eagleland side of the pond, combining as they do two of our favourite things: firearms and calories. Nine out of ten Canadians agree that there’s nothing quite like a high-speed poutine– but judging by accent [Current Concept] is an American and so his potato cannon needed a little something extra that even the second amendment doesn’t protect: fully automatic firing, with a belt feed.

Like many spud guns, this one is powered by compressed air and uses PVC for both the barrel and air reservoir; unlike most spud guns, it has a steel frame holding it together, and a 3D-printed belt-feed mechanism to bring the spuds into position, with a beefy stepper motor pulling the potatoes. Of course just sticking an extra length of pipe between resivoire and barrel would just result in 80PSI potato-scented flatulence as the air escaped betwixt the gap, so a pair of piston-actuated, 3D printed fittings slides over the plastic casings in the belt that hold the spuds. It’s not a perfect seal, but video evidence suggests it’s tight enough to get the tubers flying. Finally, the whole thing was put on a bipod mount, because– uh. Look at it. It might be light enough for one man to carry, but this is clearly a crew-served weapon, even if there’s only one guy there.

Now, there are some caveats– the air reservoir is only good for one shot, so it needs to stay hooked to an air compressor to take advantage of the repeated firings. Since it has to recharge, it’s also only firing a spud every six seconds, so while the mechanism could do “full auto”, it’s actually semiautomatic in practice as nobody’s going to sit and hold the trigger that long. Finally, we must warn you that the YouTuber behind this is trying to be funny for much of the video. Some may find his delivery leaves them in stitches; others will be left cold. There is, of course, no accounting for taste.

Oddly enough, this isn’t the first automatic air gun to grace these pages. It’s also one of the weaker potato propellers, especially compared to this MAPP-gas powered monster. Hopefully [Current Concept] doesn’t see that and get any ideas for the promised revision of his belt-fed tuber tosser, or he may get a visit from the ATF– that’s the US Bureau of Alcohol, Tobacco, and Firearms, who are way less fun to deal with than the name might imply.

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