Wearable Hacks

547 Articles

Literal Stretch-Sensing Glove Reconstructs Your Hand Poses

October 9, 2019 by 9 Comments

Our hands are rich forms of gestural expression, but capturing these expressions without hindering the hand itself is no easy task–even in today’s world of virtual reality hardware. Fret not, though, as researchers at the Interactive Geometry Lab have recently developed a glove that’s both comfortable and straightforward to fabricate while capturing not simply gestures but entire hand poses.

Like many hand-recognition gloves, this “stretch-sensing soft glove” mounts the sensors directly into the glove such that movements can be captured while hands are out of plain sight. However, unlike other gloves, sensors are custom-made from two stretchable conductive layers sandwiched between a plain layer of silicone. The result is a grid of 44 capacitive stretch sensors. The team feeds this datastream into a neural network for gesture processing, and the result is a system capable of reconstructing hand poses at 60Hz refresh rates.

In their paper [PDF], the research team details a process of making the glove with a conventional CO2 laser cutter. They first cast a conductive silicone layer onto a conventional sheet of silicone. Then, with two samples, they selectively etch away the conductive layer with the unique capacitive grid images. Finally, they sandwich these layers together with an additional insulating and glue it into a hand-shaped textile pattern. The resulting process is a classy use of the laser cutter for the design of flexible capacitive circuits without any further specialized hardware processes.

While we’re no stranger to retrofitting gloves with sensors or etching unconventional materials, the fidelity of this research project is in a class of its own. We can’t wait to see folks extend this technique into other wearable stretch sensors. For a deeper dive into the glove’s capabilities, have a look at the video after the break.

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Ask Hackaday: What’s The Perfect Hacker Smart Watch?

October 7, 2019 by 63 Comments

Since Dick Tracy all the way back in ’46, smart watches have captured the public imagination. After several false starts, the technology has gone through a renaissance in the last 10 years or so. For the average consumer, there’s been a proliferation of hardware in the marketplace, with scores of different models to choose from. For the hackers, however, pickings are a little more slim. So what is the best smart watch for the tinkerers among us? Continue reading “Ask Hackaday: What’s The Perfect Hacker Smart Watch?” →

This Biofuel Cell Harvests Energy From Your Sweat

October 4, 2019 by 11 Comments

Researchers from l’Université Grenoble Alpes and the University of San Diego recently developed and patented a flexible device that’s able to produce electrical energy from human sweat. The lactate/O2 biofuel cell has been demonstrated to light an LED, leading to further development in the area of harvesting energy through wearables.

[via Advanced Functional Materials]
The research was published in Advanced Functional Materials on September 25, 2019. The potential use cases for this type of biofuel cell within the wearables space include medical and athletic monitoring. By using biofuels present in human fluids, the devices can rely on an efficient energy source that easily integrated with the human body.

Scientists have developed a flexible conductive material made up of carbon nanotubes, cross-linked polymers, and enzymes connected to each and printed through screen-printing. This type of composite is known as a buckypaper, and uses the carbon nanotubes as the electrode material.

The lactate oxidase works as the anode and the bilirubin oxidase (from the yellowish compound found in blood) as the cathode. Given the theoretical high power density of lactate, this technology has the potential to produce even more power than its current power generation of 450 µW.

[via Advanced Functional Materials]
The cell follows deformations in the skin and produces electrical energy through oxygen reduction and oxidation of the lactate in perspiration. A boost converter is used to increase the voltage to continuously power an LED. The biofuel cells currently delivered 0.74V of open circuit voltage. As measurements for power generation had to be taken with the biofuel cell against human skin, the device has shown to be productive even when stretched and compressed.

At the moment, the biggest cost for production is the price of the enzymes that transform the compounds in sweat. Beyond cost considerations, the researchers also need to look at ways to increase the voltage in order to power larger portable devices.

With all the exciting research surrounding wearable technology right now, hopefully we’ll be hearing about further developments and applications from this research group soon!

[Thanks to Qes for the tip!]

Lighting The Way For The Visually Impaired

September 28, 2019 by 8 Comments

The latest creation from Bengali roboticist [nabilphysics] might sound familiar. His laser-augmented glove gives users the ability to detect objects horizontally in front of them, much like a cane or pole is used by the visually impaired to navigate through a physical space.

As a stand in for the physical cane, he uses the VL53L0X time-of-flight (TOF) sensor which detects the time taken for a laser source to bounce back to the sensor. Theses are much more accurate than IR distance sensors and have a much finer focus than ultrasonic sensors for excellent directionality.

While the sensors can succumb to interferences from background light or other time-of-flight sensors, the main advantages are speed of calculation (it relies on a single shot to compute the distances within a scene) and an efficient distance algorithm that simplifies the measurement of distance data. In contrast to stereo vision, which requires complex correlation algorithms, the process for extracting information for a time-of-flight sensor is entirely direct, requiring a small amount of processing power.

The glove delivers haptic feedback to the user to determine if an object is in their way. The feedback is controlled through an Arduino Pro Mini, powered remotely by a LiPo battery. The code is uploaded to the Arduino from an FTDI adapter, and works by taking continuous readings from the time-of-flight sensor and determining if the object in front is within 450 millimeters of the glove, at which point it triggers the vibration motor to alert the user of the object’s presence.

Since the glove used for the project is a bicycle glove, the form factor is straightforward — the Arduino, motor, battery, and switch are all located inside a plastic box on the top of the glove, while the time-of-flight sensor sticks out to make continuous measurements when the glove is switched on.

In general, the setup is fairly simple, but the idea of using a time-of-flight sensor rather than an IR or sonar sensor is interesting. In the broader usage of sensors, LIDARs are already the de facto sensor used for autonomous vehicles and robotic components that rely on distance sensing. This three-dimensional data wouldn’t be much use here and this sensor works without mechanical moving parts since it doesn’t rely on the point-by-point scan from a laser beam that LIDAR systems use.

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Fighting Household Air Pollution

September 24, 2019 by 35 Comments

When Kenyan engineer [Aloise] found out about the health risks of household air pollution, they knew there had to be a smart solution to combatting the problem while still providing a reasonable source of energy for families cooking without the luxury of cleaner fuels. Enter OpenHAP, a DIY household air pollution monitor that provides citizen scientists and researches the means to measure air particulates in developing countries.

The device is based on an ESP32 communicating with a ZH03B Particulate matter sensor over UART; a DS3231SN real-time clock (RTC), temperature and humidity sensor, and MLX90640 2D thermal sensor array over I2C; and wirelessly sending the data received to a Bluetooth low energy wrist-strap beacon and an Internet enabled phone. The device also uses a TCA9534 GPIO expander to control the visual and auditory notifiers (buzzers and LEDs) and to interface to a SD card.

The project uses the libesphttpd project modified for the ESP32 for the webserver, which is used to stream data to a mobile handset or computer using the WiFi capabilities of the ESP32. The data includes real-time sensor information, system status, storage media status, visualizations of the thermal array sensor data (to ensure the camera is facing the source of heat), and tag information to test the limits of the Bluetooth tag with regards to distance.

Power input is provided through a Micro-USB connector, protected with a TVS diode and a Schottky diode in series to prevent reverse power flow.

The project was tested in two real-life scenarios: one with a household in rural Kenya and another with an urban low-income family of four. In the first test, the family used a three stone open fire stove. A FLiR thermal camera captured the stove temperatures, while a standard camera was enough to capture the high levels of smoke inside the kitchen. The readings from OpenHAP were high enough to exceed the upper detection threshold for the particulate sensor, showing that the woman cooking in the house was receiving the equivalent of 8 cigarettes a day, about 8 x the WHO’s recommended particulate levels.

Within the second household, a typical energy mix of charcoal briquettes and kerosene was typically used for cooking, with kerosene used during the day and briquettes used at night. The results from measuring pollution levels using OpenHAP showed that the mother and child in the household regularly received around 1.5 x the recommended limit of pollutants, enough to lead to slow suffocation.

There’s already immense potential for this project to help researchers test out different energy sources for rural households, not to mention the advantage of having a portable low-energy pollution monitor for citizen scientists.

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Laser Crown Shines At Night

September 16, 2019 by 6 Comments

Sometimes you need something really flashy to complete an outfit. Whether it’s a sparkly pair of earrings or a stylish necklace, accessories are key to competing on the fashion battlefield. For those who want to bring some serious firepower, [p3nguin’s] laser crown might be just what the doctor ordered.

At the outset, we should state the crown only uses lasers in its construction, for cutting felt and acrylic. The light source is a Neopixel ring from Adafruit, capable of bringing the vibrant colors without risk of eye damage. The ring is then assembled with a series of snap-together acrylic parts and a felt cap, with slots for hair pins to keep the crown in place on the wearer’s head. A Trinket drives the show, with a LiPo battery used as a lightweight power supply.

It’s a nice build that’s sure to draw plenty of attention. We see some great wearables around these parts; this EL jacket is a particular favorite. Video after the break.

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An RFID Ring For The Body Mod Squeamish

September 8, 2019 by 27 Comments

Some people get inked, while others get henna or those water transfer tattoos you might find in a box of Cracker Jack. [Becky] wanted the benefits of having an RFID tag in her finger — unlock doors or log into your computer with a swipe of your finger — but wasn’t ready to get an implant. Her solution: make an artistic ring that conceals a tiny glass capsule RFID tag.

Besides not having to shove some tech under your epidermis, there are a few other advantages: you can change out tags as easy as changing rings, for one. You can also easily loan your ring to someone just as you might give them keys to your door.

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