Wearables have been a big part of the ever-growing fitness industry since they first hit the market. Biosensors, flexible materials, and scalable manufacturing techniques helped revolutionize how we track fitness and health parameters. Wearables provide an accurate and non-invasive method to keep track of vitals, making them a perfect fit for precise, real-time diagnoses and health monitoring.
Recently, a team at the University of San Diego demonstrated a prototype wearable device that could run on sweat. And the fitness industry is buzzing about the possibilities this invention could bring.
With each new version or product, these technological marvels evolve and bring something new to the table. Some of the many innovations have included IoT integration, artificial intelligence (AI), and more enhanced self-powering energy solutions (like the one proposed by the team from the University of San Diego).
A Look at Self-Powered Wearables
Self-powered wearables are a natural next step for this technology. One of the major current problems faced by wearable users is the need for an external power supply. Your device must be removed and charged regularly, which means that you’re often not tracking any of your vitals.
But what if you had a way to charge your device without taking it off? This function would pave the way for enhanced wearables and make ongoing health tracking even more accessible.
The essential energy sources like biochemical energy, biomechanical energy, solar energy, and thermal energy can be converted into electricity and used in self-powered wearable devices. These devices could operate continuously using energy harvesters.
What Are Energy Harvesters?
As mentioned earlier, energy harvesters are crucial if we’re going to make self-powered wearable devices a reality. The three major types of energy harvesters include:
- TENG (triboelectric nanogenerator)
- BFC (biofuel cell)
- SC (solar cell)
The crucial components include the biosensors (which could be chemical, physical, or multimodal) and the active sensing components such as the TENG and BFC systems.
Using Sweat to Power Your Wearables
To make these wearables a reality, you must find the perfect energy source. It should be readily available, tracked and sensed with ease, and efficiently converted to electrical energy. And developers have found the answer. It’s sweat.
Our bodies burn around 2000 to 2500 calories per day, depending on our metabolism. This level of energy is sufficient to power a smartphone. And the power demand of a simple wearable device is much lower, ranging from 1 milliwatt to a few dozen milliwatts. This means that harvesting energy for wearables is quite feasible.
Bodily heat and surrounding light can power small wearables, but they don’t provide enough energy for advanced wearable prototypes.
Sweat, on the other hand, holds more promise as a biofuel. It contains certain chemicals that can be used in biofuel cells. Specifically, sweat can act as a substitute for the electrolyte used in a biofuel cell.
It’s this principle that the team at the University of San Diego relied on to develop their prototype of a wearable device that runs on sweat. Specifically, it uses an SC–BFC hybrid system for power. That’s a combination of solar cell and biofuel cell energy harvesting. This system delivers a stable power output over long charging periods while boosting the BFC voltage output and demonstrating a favorable cycling ability.
As promising as it sounds, using sweat as a biofuel will only be applicable as long as the user is, well, sweating. Exercise and other athletic activities that make people sweat are required. And not everyone can (or wants to) meet that requirement regularly.
In the future, wearables must find alternative workarounds that are more accessible to everyone’s lifestyle and abilities. But today, athletes and those with a regular exercise routine have exciting new wearables on the horizon.