Hacking The Xiaomi Mi Band 8 With Custom Firmware

December 7, 2023 by Maya Posch 11 Comments

Over the past years, fitness trackers have gone from fairly unobtrusive bands that relied mostly on smartphone apps for interaction to essentially being fashion statements and smart watches, with large screens and impressive specs. The Xiaomi Mi Band 8 is no exception, with a zippy MCU and a 1.62″ AMOLED screen that just asks for some serious rick-rolling. This was a challenge which [Aaron Christophel] was all too happy to accept, resulting in some reverse-engineering and flashing of custom firmware onto one of these marvels of modern wearable technology.

Block Diagram for the Apollo4 Blue Lite. (Credit: Ambiq)

The Mi Band 8 is built around an Ambiq Apollo4 Blue Lite MCU which features a Cortex-M4 core for applications, along with a Bluetooth LE radio and a lot of SRAM and Flash. This naturally implies an SWD interface for programming, which was mostly a matter of reverse-engineering the PCB to find the locations for these signals and realizing that the original firmware disables the SWD interface on boot. Unfortunately the Ambiq SDK requires you to create an account, but you can get the basics from [Aaron]’s GitHub project. It appears that for BLE you do need the full SDK, and OTA updates feature a signing check, so physical access is required.

So far the display, touchscreen and light sensor are working, with the remaining peripherals just a matter of time. With a list price of around $64 for one of these fitness bands with a 192 x 490 touch-enabled AMOLED display and a variety of health-related sensors, they’d seem to be a fun toy to hack, especially when found on sale or used.

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LED Ring Brings The Bling

November 28, 2023 by Kristina Panos 10 Comments

We’ve seen our share of light-up jewelry over the years, but for some reason — probably power — it’s almost always earrings or necklaces. So when we saw [ROBO HUB]’s LED ring, we had to check it out. It involves a bit of behind-the-scenes action in the form of a battery holder that you palm, but the end effect is quite cool.

Essentially, this is a 3D printed ring with SMD LEDs painstakingly soldered together in parallel along a pair of thin copper wires. The ring itself is in two parts: a base, and a cover to diffuse and protect the LEDs. A pair of wires run out from the ring and connect to a printed coin cell holder.

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In New Doctor’s Office, Stethoscope Wears You

November 26, 2023 by Al Williams 28 Comments

The medical professional wearing a stethoscope is a familiar image, but Northwestern University wants to change that. Instead of someone hanging an ancient device around their neck to listen inside of you, they want to put sticky sensors on patients to continuously monitor sounds from hearts, lungs, and the GI tract.

The tiny devices stick to your skin and wirelessly beam audio to clinicians for analysis. They’ve tested the devices on people ranging from people with chronic lung disease to premature babies. In fact, you can hear breath sounds (and crying) from a microphone attached to a baby in the video below. The device uses noise suppression to remove the crying sounds effectively.

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Building Penny’s Computer Watch From Inspector Gadget

October 31, 2023 by Kristina Panos 4 Comments

When you help your bumbling Uncle Gadget with all kinds of missions, you definitely need a watch that can do it all. Penny’s video watch from Inspector Gadget has a ton of features including video communication with Brain and Chief Quimby, a laser, a magnet, a flashlight, a sonar signal, and much more.

To round out her Penny costume, [Becky Stern] has created a 3D printed version of Penny’s incredibly smart watch. It listens for Penny’s iconic phrase — come in, Brain! — and then loads a new picture of Brain on the rounded rectangle TFT display. Inside the watch is an Arduino Nicla Voice, which has to be one of the tinier machine learning-capable boards out there.

[Becky] created the watch case in Tinkercad and modified a watch band from Printables to fit her wrist. With such a small enclosure to work with, [Becky] ended up using that really flexible 30 AWG silicone-jacketed wire for all the fiddly connections between the Arduino and the screen.

After getting it all wired up to test, she found that the screen was broken, either from pressing it into the enclosure, or having a too-close encounter with a helping hands. Let that be a lesson to you, and check out the build video after the break.

More interested in Uncle Gadget’s goodies? Check out these go-go-Gadget shoes and this propeller backpack for skiers.

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Take The Tedium Out Of Fabric Cutting, Make The Laser Do It

October 29, 2023 by Donald Papp 8 Comments

Fabric must be cut before it can be turned into something else, and [fiercekittenz] shows how a laser cutter can hit all the right bases to save a lot of time on the process. She demonstrates processing three layers of fabric at once on a CO2 laser cutter, cutting three bags’ worth of material in a scant 1 minute and 29 seconds.

The three layers are a PU (polyurethane) waterproof canvas, a woven liner, and a patterned cotton canvas. The laser does a fantastic job of slicing out perfectly formed pieces in no time, and its precision means minimal waste. The only gotcha is to ensure materials are safe to laser cut. For example, PU-based canvas is acceptable, but PVC-based materials are not. If you want to skip the materials discussion and watch the job, laying the fabric in the machine starts around [3:16] in the video.

[fiercekittenz] acknowledges that her large 100-watt CO2 laser cutter is great but points out that smaller or diode-based laser machines can perfectly cut fabric under the right circumstances. One may have to work in smaller batches, but it doesn’t take 100 watts to do the job. Her large machine, for example, is running at only a fraction of its full power to cut the three layers at once.

One interesting thing is that the heat of the laser somewhat seals the cut edge of the PU waterproof canvas. In the past, we’ve seen defocused lasers used to weld and seal non-woven plastics like those in face masks, a task usually performed by ultrasonic welding. The ability for a laser beam to act as both “scissors” and “glue” in these cases is pretty interesting. You can learn all about using a laser cutter instead of fabric scissors in the video embedded below.

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Arduwatch Design Study Is Compelling Concept For DIY Smartwatch

October 23, 2023 by Lewin Day 10 Comments

Smartwatches are a battleground these days, with smartphone manufacturers vying to have the prettiest, sleekest, and longest-lasting device on the market. Meanwhile, DIY efforts continue to improve in sophistication as better components become available. [Rocky Bergen’s] Arduwatch is a particularly appealing design study, with such visual flair that we’d love to see it become a reality.

The design was inspired by the Arduboy, itself a lightweight homebrewed handheld console of impressive simplicity. [Rocky]’s concept hinges on taking that credit-card sized platform and repurposing it as a wearable device instead. The squared-off, retro design of the Arduwatch is appealing, as is its simple four-button interface and the bright colors [Rocky] chose to show it off. Ultimately, too, its low-resolution display would realistically be more than suitable for a great variety of simple smartwatch tasks, which often just involve displaying notifications and the like.

[Rocky’s] work may just be a design study, but it’s well thought out and eminently viable. We’d love to see how well this design could work in the real world, particularly if built with some nice resin-printed parts paired with a quality watch strap.

If you’ve heard of [Rocky Bergen] before, it may be due to his exquisite collection of retrocomputer papercraft designs. If you’ve been cooking up your own DIY smartwatch ideas, don’t hesitate to hit up the tipsline!

Adobe Scientist Cuts A Dash With LCD Shifting Dress

October 22, 2023 by Richard Baguley 64 Comments

Adobe research scientist [Christine Dierk] showed off an interesting new project at the Adobe Max conference: Project Primrose, a dress covered with a series of liquid crystal panels that could react to movement, changing the design of the dress. Now, Adobe has released a paper showing some of the technical details of the process.

The paper is from the User Interface & Software (UIST) conference in 2022, so the examples it uses are older: it discusses a canvas and handbag. The dress uses the same technology, though, draped over a scientist rather than a frame. If you can’t access the version from UIST, [Dierk] has a free version here.

The dress uses Polymer-dispersed Liquid Crystal (PDLC) panels from the wonderfully named Shanghai HO HO Industry Co and is designed for use in windows and doors for privacy. It uses an Indium Tin oxide-coated PET film that is opaque by default but becomes transparent when a voltage difference is applied across the material.

These panels are shaped to a hexagonal shape, then wired together with flexible PCBs in a daisy chain. Interestingly, [Dierk] found that the smaller the panels were made, the lower the voltage was required to trigger them. For their canvas example, they dropped the voltage to a much safer -15V to 15V levels to trigger the two states, which is much safer for a wearable device.

The panels are also not completely transparent when triggered: the paper describes them as having a “soft ivory” look when they are overlaying a reflective material. Greyscales can also be made using Pulse Coded Modulation (PCM) to vary the panel’s transparency. Driving the panels at 3.2KHz, they created 64 shades of grey.

The main controller is a custom PCB with a Teensy 4.1 and a BlueFruit LE SPI module. The power comes from two 14.8V LiPo batteries, with converters to power the chips and switch modules so the Teensy can switch the -15 and +15V levels for the panels directly from each battery.

The array is made from modules, each with four panels connected to a controller PCB, which has several Analog Signal Device (ASD) ADG1414 chips. These receive the signals from the bus with switch registers to switch the panels individually.

Rather cleverly, [Dierk] uses the bus that daisy chains the modules together to deliver both power and the bus signal that controls the panels, using the -15 and +15V levels modulated with a 50Hz square wave to create the bus signal and power the panels at the same time. That’s a neat hack that reduces the complexity of the modules significantly.

The Teensy 4.1 controls the whole system and can use its IMU to sense movement and change the pattern accordingly. You don’t get to see the system’s electronics in the dress video, but they claim that the canvas example took just 0.58 Watts to drive, so the dress probably only needs a few watts.

It is a fascinating build (and a rather cute dress), and has a lot of potential. What would you do with this?

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