Wireless Water Detector Hooks Up To Home Assistant

September 22, 2022 by Zoe Skyforest 19 Comments

Water damage can quickly make even the nicest buildings unliveable. [Andres Leon] suffered a small flood from an air conditioning unit, and wanted to avoid such issues in future. Thus, he built a wireless monitor to solve the problem.

The device is based on the ESP8266, allowing it to wirelessly communicate with Home Assistant. Thus, if it detects water via its rust-proof probes, it can notify Home Assistant via an MQTT message. From there, Home Assistant can advise the home owner remotely via phone and email. Plus, just for completeness, there’s a loud buzzer in the unit that goes off when water is detected, too. Thanks to a 2500 mAh lithium-polymer battery on board, the device can run for up to 5 months between recharges.

Integrating warning systems into one’s smart home system can be particularly useful when one is away for long periods. Things like water leaks tend to do damage over time when we’re not paying attention, so any IoT device that can assist in this regard is helpful. If you want to investigate the cause of a difficult leak, though, this other project may help. Video after the break.

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3D Print Yourself A Tiny Steam Train Complete With Smoke Effects

September 21, 2022 by Zoe Skyforest 10 Comments

Model trains are fun, but sometimes little whirring motors in electric models feel a long way from the hulking metal beasts of the real railways. [Lewis] of [DIY Machines] adds back some of the flavor with this little steam train build, smoke effects included!

The body of the train itself is 3D printed in PLA. It’s designed to O-gauge scale, and comes complete with models for 3D printed track as well. The parts are given a coat of paint to better approximate the finish of the real thing; sometimes bare plastic just won’t suffice, after all.

Propulsion is thanks to an onboard battery and a simple gearmotor, driven by a HG7881 motor driver. An ESP32-CAM is responsible for running the show, allowing the train to be commanded wirelessly. As a bonus, the camera is mounted in the very front of the train, allowing one to watch a livestream of its progress about the tracks. Meanwhile, the smoke effect is thanks to a small water atomizer fitted in the train’s chimney, which makes the train look that little bit more authentic.

The combination of a self-powered train and 3D-printed tracks is a compelling one. [Lewis] has been able to leave his PETG 3D-printed track outside for over two years and it’s still in working order. That’s not something easy to achieve when using metal rails to deliver power.

Overall, this is a fun way to get into building your own model trains, and is a lot more hands-on than simply buying pre-built models from a store. From there, the sky is really the limit for your creativity! Video after the break.

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Trojans Can Lurk Inside AVR Bootloaders

September 21, 2022 by Zoe Skyforest 52 Comments

If there’s one thing we’ve learned over the years, it’s that if it’s got a silicon chip inside, it could be carrying a virus. Research by one group focused on hiding a trojan inside an AVR Arduino bootloader, proving even our little hobbyist microcontrollers aren’t safe.

The specific aim of the research was to hide a trojan inside the bootloader of an AVR chip itself. This would allow the trojan to remain present on something like a 3D printer even if the main firmware itself was reinstalled. The trojan would still be able to have an effect on the printer’s performance from its dastardly hiding place, but would be more difficult to notice and remove.

The target of the work was the ATmega328P, commonly used in 3D printers, in particular those using the Marlin firmware. For the full technical details, you can dive in and read the research paper for yourself. In basic terms, though, the modified bootloader was able to use the chip’s IVSEL register to allow bootloader execution after boot via interrupt. When an interrupt is called, execution passes to the trojan-infected bootloader’s special code, before then returning to the program’s own interrupt to avoid raising suspicion. The trojan can also execute after the program’s interrupt code too, increasing the flexibility of the attack. Continue reading “Trojans Can Lurk Inside AVR Bootloaders” →

Old Barcode Scanner Motherboards Live Again

September 21, 2022 by Zoe Skyforest 1 Comment

Sometimes, hacking is just for the pleasure of diving into the secrets of old hardware. That was very much the case when [glitch] and a friend started hacking on some old Intel 8080 boards that had been living in the junk pile for too long.

The boards in question were motherboards from Identicon barcode scanners, running the Intel 8080 CPU. Hacking on the 8080 is a little different, with the ancient CPU requiring three separate voltages to run. However, with the power rails figured out and power applied, it was possible to get the old boards up and running.

The boards were first run with test ROMs which showed the 8080 CPU to be functional. The ROMs hosted a simple program which got the 8080 to spit out the word “HELO” on to an HP HDSP-2416 ASCII character display. From there, the barcode scanner boards were installed in a chassis and hooked up to a bigger Siemens character display, and the memory was mapped out.

The result was that [glitch] and co were able to largely reverse engineer the Identicon hardware, learning it was fairly similar to the Intel MCS-80 reference design of the era. They were able to get code running on the platform, access the RAM, and fit a larger 8-character display. However, without the original barcode scanner attachment, the boards weren’t able to return to their original duty.

As far as hacks go, it’s pretty old school. The boards don’t talk to Twitter, nor run the lights or help with the dishes. However, plenty of fun was had seeing if this old metal could be made to follow instructions once more. Hacking for the pleasure of it is always a good thing by our book!

A 3D Printed Marble Run Features Neat Elevator Linkage

September 21, 2022 by Zoe Skyforest 20 Comments

There’s seldom anything as joyful and relaxing to watch as a simple marble run. Of course, the thing about letting marbles fall under gravity is that you eventually need to lift them back up again. The Marblevator has a mechanism that does just that.

Overall, the build features a relatively simple marble run. It consists of just six 3D printed ramps which the marble tumbles down in just a few seconds. However, the real magic is in the mechanism that restores the marbles from the bottom of the run all the way back to the top.

A motor turns a gear, which then rotates a crank leading to a multi-link rhombus. On one corner of the rhombus is a small protrusion with a magnet attached, which picks up the marbles from the bottom of the run. As the mechanism turns, the rhombus shifts and brings the marble-carrying arm to the top of the marble run. There, it’s grabbed by another magnet, which holds the marble for a moment before letting it drop back down through the run.

It’s a simple project that nonetheless would make a brilliant desk toy. It’s also a great way to learn about linkage analysis and designing such systems on your own. If you’re big into marble runs, you might also consider procedurally generating them. Video after the break.

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Mechanical Color Picker Types Hex Codes For You

September 21, 2022 by Zoe Skyforest 18 Comments

Hex codes are a simple, unambiguous way to designate colors in digital media. However, going from a color in your head to a hex code can be difficult for the unpracticed. [Guy Dupont] built a little gadget by the name of the Dial Toner to do it for him (Nitter).

The Dial Toner has two dials for each color channel – Red, Green, and Blue. By turning the dials, one can choose a given color in the 8-bit RGB color space, and that color is then displayed on the device’s included RGB LED. Once selected, the button can be pressed to type the selected color’s hex code into a text box. The Dial Toner runs on a Xiao RP2040 microcontroller board, and is coded in CircuitPython.

[Guy] hopes to sell the Dial Toner on Etsy in future, and is even working on a CMYK version for print addicts. We’ve featured [Guy]’s work here before, too, in the form of his extended-play HitClips cartridges. Video after the break.

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3D Printed String Vase Shows What’s Possible

September 20, 2022 by Zoe Skyforest 15 Comments

Overhangs are the bane of the melty-plastic 3D printing world. Often, we try to avoid them with creative print alignments, or we compensate with supports. However, [3DPrintBunny] decided to embrace overhangs in the extreme in the design of her creative 3D-printed string vase.

The design is intended to be printed with a larger nozzle, on the order of 0.8 mm or so, at a layer height of 0.6 mm. Under these conditions, the printer nozzle bridges the gap between the vase’s pillars with a single string of molten filament. With the settings just so, the molten filament stays attached during the bridging operation, and creates a fine plastic string between the pillars. Repeat this across the whole design, and you get an attractive string vase.

Amazingly, [3DPrintBunny] didn’t have to do any fancy slicer tricks to achieve this. Stock slicer settings got the job done just fine, and she reports that the model should print on most FDM printers. For her own examples, she printed in a special silver/bronze dual color PLA filament.

It recalls us of efforts to create synthetic hair-like fibers by taking advantage of stringing in 3D printers. Video after the break. Continue reading “3D Printed String Vase Shows What’s Possible” →