Custom Firmware For Even Cheaper Bluetooth Thermometers

December 21, 2024 by Tom Nardi 31 Comments

Readers may recall when we first covered the $5 Xiaomi LYWSD03MMC temperature and humidity sensor back in 2020. Prolific hacker [Aaron Christophel] wrote a custom firmware for the affordable gadget that was so capable and well implemented that it kicked off a whole new community.

It’s recently been brought to our attention that the Xiaomi thermometer has become so popular that clones have started popping up. Often sold under the Tuya brand, these versions look very similar to Xiaomi’s offering but can be had for as little as $1 each from the usual Chinese importers. Even better, they’ve got their very own open-source custom firmware.

The firmware comes from [pvvx], who also helms the most active fork of [Aaron]’s original firmware for the Xiaomi thermometer. Doing a bit of spot-checking between the repositories, it’s not immediately clear that any meaningful code is shared between the two projects. However, once installed, they offer similar capabilities to the user, such as integration with Home Assistant. Perhaps the most significant difference between the two projects is that, at least for the initial flash, you need to hook the Tuya units up to your computer with a USB serial adapter. Considering that one of the highlights of the Xiaomi custom firmware was its exceptionally easy wireless installation, this is a considerable step backward.

Below is a video from a few months back that [Maker’s Fun Duck] put together, where he takes apart one of these clones and shows the installation process for the custom firmware. Our overall impression is that it’s probably worth the few extra dollars to get the original Xiaomi hardware, although the display on the clone seems much brighter. In any event, we’re always happy to see the community coming up with free and open-source firmware for an otherwise locked-down gadget.

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Updated Mouse Ring Does It With A Joystick

December 10, 2024 by Kristina Panos 9 Comments

Have you ever wished for easy mouse controls to go along with your VR headset experience? Or maybe you just want a cooler way to mouse in general. In any case, look no further than [rafgaj78]’s Bluetooth Mouse Ring project.

This is version two, which of course comes with several improvements over version one. The biggest change is from tactile buttons to a joystick input. [rafgaj78] also did away with the power switch, using deep-sleep mode instead. Version two is easier to assemble and offers improved ergonomics, as well as a range of ring sizes.

Like the first version, this ring runs on a Seeed Xiao nRF52840 and is programmed in CircuitPython. There are two modes to choose from. In one mode, the joystick does left and right mouse click and wheel up and down, while the push action recovers the micro from deep sleep. In the other mode, the joystick axis is a mouse pointer mover, and you push down to left click.

We really like this sleek design, and [rafgaj78] has great instructions if you want to build your own. This isn’t the first cool mouse ring we’ve seen, and it certainly won’t be the last.

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Folding Keyboard Mod

December 5, 2024 by Kristina Panos 3 Comments

Let’s face it, failed Kickstarters are no good. But they can spark good things, like real versions of technologies that might have actually been faked for the platform. A touchscreen mouse, for instance, with shortcuts that can be programmed for various applications.

A DIY mouse with a large touch screen. — Image by [Sam Baker] via Hackaday.IO

This story is one of scope creep, as [Sam Baker] says in the project details. At first, he thought he could just basically duct tape a touchscreen with shortcuts to an existing mouse. A couple of mouse teardowns later, [Sam] arrived at the conclusion that things would not be so simple.

After some digging around, [Sam] found a repository where someone created a way to communicate with the ADNS-5050 optical sensor, so [Sam] started by creating a breakout board for this sensor. By combining that with an ESP32 dev board and a touchscreen, [Sam] had his shortcut mouse.

Does it work? Yes. Is it useful? Well, yes. And also no. The beauty part of using a regular mouse is that you don’t have to look down at it to know where the buttons are. In the future, [Sam] would like to implement some kind of buttons for tactility. In the meantime, haptic feedback could be nice.

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Bluetooth Dongle Gives Up Its Secrets With Quick Snooping Hack

November 14, 2024 by Dan Maloney 5 Comments

There’s a lot going on in our wireless world, and the number of packets whizzing back and forth between our devices is staggering. All this information can be a rich vein to mine for IoT hackers, but how do you zero in on the information that matters? That depends, of course, but if your application involves Bluetooth, you might be able to snoop in on the conversation relatively easily.

By way of explanation, we turn to [Mark Hughes] and his Boondock Echo, a device we’ve featured in these pages before. [Mark] needed to know how long the Echo would operate when powered by a battery bank, as well as specifics about the power draw over time. He had one of those Fnirsi USB power meter dongles, the kind that talks to a smartphone app over Bluetooth. To tap into the conversation, he enabled Host Control Interface logging on his phone and let the dongle and the app talk for a bit. The captured log file was then filtered through WireShark, leaving behind a list of all the Bluetooth packets to and from the dongle’s address.

That’s when the fun began. Using a little wetware pattern recognition, [Mark] was able to figure out the basic structure of each frame. Knowing the voltage range of USB power delivery helped him find the bytes representing voltage and current, which allowed him to throw together a Python program to talk to the dongle in real-time and get the critical numbers.

It’s not likely that all BLE-connected devices will be as amenable to reverse engineering as this dongle was, but this is still a great technique to keep in mind. We’ve got a couple of applications for this in mind already, in fact.

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[miko_tarik] wearing diy AR goggles in futuristic setting

Pi Zero To AR: Building DIY Augmented Reality Glasses

November 4, 2024 by Heidi Ulrich 36 Comments

If you’re into pushing tech boundaries from home, this one’s for you. Redditor [mi_kotalik] has crafted ‘Zero’, a custom pair of DIY augmented reality (AR) glasses using a Raspberry Pi Zero. Designed as an affordable, self-contained device for displaying simple AR functions, Zero allows him to experiment without breaking the bank. With features like video playback, Bluetooth audio, a teleprompter, and an image viewer, Zero is a testament to what can be done with determination and creativity on a budget. The original Reddit thread includes videos, a build log, and links to documentation on X, giving you an in-depth look into [mi_kotalik]’s journey. Take a sneak peek through the lens here.

Creating Zero wasn’t simple. From designing the frame in Tinkercad to experimenting with transparent PETG to print lenses (ultimately switching to resin-cast lenses), [mi_kotalik] faced plenty of challenges. By customizing SPI displays and optimizing them to 60 FPS, he achieved an impressive level of real-time responsiveness, allowing him to explore AR interactions like never before. While the Raspberry Pi Zero’s power is limited, [mi_kotalik] is already planning a V2 with a Compute Module 4 to enable 3D rendering, GPS, and spatial tracking.

Zero is an inspiring example for tinkerers hoping to make AR tech more accessible, especially after the fresh news of both Meta and Apple cancelling their attempts to venture in the world of AR. If you are into AR and eager to learn from an original project like this one, check out the full Reddit thread and explore Hackaday’s past coverage on augmented reality experiments.

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The Design Process For A Tiny Robot Brain

October 20, 2024 by Bryan Cockfield 13 Comments

As things get smaller, we can fit more processing power into devices like robots to allow them to do more things or interact with their environment in new ways. If not, we can at least build them for less cost. But the design process can get exponentially more complicated when miniaturizing things. [Carl] wanted to build the smallest 9-axis robotic microcontroller with as many features as possible, and went through a number of design iterations to finally get to this extremely small robotics platform.

Although there are smaller wireless-enabled microcontrollers, [Carl] based this project around the popular ESP32 platform to allow it to be usable by a wider range of people. With that module taking up most of the top side of the PCB, he turned to the bottom to add the rest of the components for the platform. The first thing to add was a power management circuit, and after one iteration he settled on a circuit which can provide the board power from a battery or a USB cable, while also managing the battery’s charge. As for sensors, it has a light sensor and an optional 9-axis motion sensor, allowing for gesture sensing, proximity detection, and motion tracking.

Of course there were some compromises in this design to minimize the footprint, like placing the antenna near the USB-C charger and sacrificing some processing power compared to other development boards like the STM-32. But for the size and cost of components it’s hard to get so many features in such a small package. [Carl] is using it to build some pretty tiny robots so it suits his needs perfectly. In fact, it’s hard to find anything smaller that isn’t a bristlebot.

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DIY 3D-Printed Arduino Self-Balancing Cube

October 13, 2024 by Heidi Ulrich 16 Comments

Self-balancing devices present a unique blend of challenge and innovation. That’s how [mircemk]’s project caught our eye. While balancing cubes isn’t a new concept — Hackaday has published several over the years — [mircemk] didn’t fail to impress. This design features a 3D-printed cube that balances using reaction wheels. Utilizing gyroscopic sensors and accelerometers, the device adapts to shifts in weight, enabling it to maintain stability.

At its core, the project employs an Arduino Nano microcontroller and an MPU6050 gyroscope/accelerometer to ensure precise control. Adding nuts and bolts to the reaction wheels increases their weight, enhancing their impact on the cube’s balance. They don’t hold anything. They simply add weight. The construction involves multiple 3D printed components, each requiring several hours to produce, including the reaction wheels and various mount plates. After assembly, users can fine-tune the device via Bluetooth, allowing for a straightforward calibration process to set the balancing points.

If you want to see some earlier incarnations of this sort of thing, we covered other designs in 2010, 2013, and 2016. These always remind us of Stewart platforms, which are almost the same thing turned inside out.

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