In today's advanced technological era, the prevalence and importance of electrochemical sensors are rapidly growing. Quantifying chemicals can enhance safety, efficiency, and awareness across various fields such as medical and environmental sciences, industrial materials, and food processing. When you combine this sensing capability with low-power analog front-end (AFE) devices, low-power Bluetooth® technology, and integrate it with IoT technology for remote monitoring, the effectiveness of these solutions can be further enhanced. This article will introduce the design principles of electrochemical sensors, the development of applications in remote healthcare monitoring, and the related solutions offered by onsemi.
Electrochemical sensors promote scientific understanding and improve quality of life
Interconnected electrochemical sensors can promote scientific understanding and improve our quality of life. Solutions such as wearable devices that monitor blood glucose levels for diabetes patients, gas detectors for assessing environmental contaminants, histamine sensors for improving food safety, or industrial potentiostats and corrosion sensors play a crucial role in the modern world.
A typical electrochemical sensor setup in electronic engineering involves a three-electrode system. The core of the sensor contains three main parts: the working electrode (WE), where electrochemical reactions occur, generating electron flow and current production; the counter electrode (CE), which balances the redox reactions at the working electrode for accurate sensing; and the reference electrode (RE), which measures the potential of the working electrode and provides feedback for the counter electrode's voltage. Finally, the current produced by the working electrode is converted into a voltage. Through additional digital processing and wireless communication, robust connected solutions can be built, providing insights into the environment around us and our bodies conditions.
Electrochemical sensors are critical in many remote patient monitoring applications. For example, continuous glucose monitoring (CGM) is a key component of diabetes management, a chronic disease affecting 1 in 11 people globally. The CGM device market is expected to grow at a compound annual growth rate (CAGR) of 9% from 2023 to 2032.
In environmental settings, such as applications measuring air pollution and quality, electrochemical sensors can detect gases like carbon monoxide, hydrogen sulfide, and oxides of nitrogen and sulfur. In food production, handheld portable devices and larger automated electrochemical detection solutions are used to ensure proper taste and to check for allergens or hazardous chemicals.
Pairing AFE devices with electrochemical sensors enables precise measurements, which are not only crucial for healthcare and industrial processes but also contribute to advancing scientific knowledge. For instance, wearable or portable medical devices can continuously monitor blood glucose levels remotely, offering unprecedented insights for researchers and accelerating innovation to benefit humanity globally.
Remote monitoring provides more convenient patient care services
As the population ages, there is growing attention on personal health and well-being, placing increasing pressure on healthcare professionals to diagnose, monitor, and treatments conditions. Until now, receiving a diagnosis or undergoing continuous monitoring required trips to medical facility such as doctors' offices, clinics, or hospitals. However, given people's busy lives, the time and effort needed for transportation is not always convenient, especially for those requiring long-term monitoring, which can become a significant burden.
Modern technologies, such as connected portable monitors, are rapidly transforming this scenario. It is now possible to perform simple, non-invasive monitoring without the need to visit a medical facility. In fact, some highly portable devices can record critical medical information while the patient continues with their normal life. This not only eases the strain on healthcare institutions but also reduces costs, relieving hospital loads by allowing patients to determine if a physical visit is necessary based on their condition.
In many less developed regions, there may not be suitable medical facilities available, or existing healthcare institutions may be overcrowded. In such areas, remote monitoring could be the only viable way to obtain life-changing diagnostic results. Remote monitoring enables patients to receive medical care in the comfort and safety of their own homes, reducing the risk of cross-infection from contact with others in hospitals.
Additionally, as healthcare improves, global life expectancy continues to rise. Coupled with the increasing prevalence of non-communicable diseases such as cancer, diabetes, and chronic respiratory diseases (which now account for 7 of the top 10 causes of death worldwide), the demand for remote body monitoring is growing faster than ever before.
onsemi’s electrochemical measurement and wireless transmission solutions
onsemi recently announced the launch of the CEM102, a state-of-the-art miniatured analog front-end (AFE) designed for accurately electrochemical and amperometric current measurements. When paired with the RSL15, a Bluetooth 5.2-certified wireless microcontroller, the RSL15 offers industry-leading low-power, secure Bluetooth Low Energy (BLE) technology. This solution allows designers to develop extremely accurate, low-power, and compact sensing applications.
Compared to individual solution setups, onsemi’s CEM102 + RSL15 solution offers higher precision, lower noise, and reduced power consumption. It simplifies the bill of materials (BoM) and provides greater configuration flexibility, ultimately freeing up development resources. Importantly, this flexibility makes it a solution not only for electrochemical based sensors measurements but also for many types of sensors that require precise small-current measurements.
The CEM102 + RSL15 platform supports two battery options, 1.3 - 1.65 V and 2.375 - 3.6V. In continuous conversion mode with an 18-bit ADC, the device consumes just 3.5 µA in active measurement mode, allowing market-leading 14-day operation on just a 3 mAh battery. With its compact 1.884 x 1.848 mm packaging and the ability to use one to four electrodes, it enables the creation of smaller, more efficient wearable healthcare solutions, enhancing the user experience. To simplify development, the CEM102 + RSL15 product offers cutting-edge hardware, extensive development support, and firmware, software, and iOS/Android™ demo applications, facilitating solutions for continuous sensing of multiple sensors.
The accurate detection and measurement of various chemical currents open new doors for scientific progress. Its small form factor and industry-leading low-power consumption allow further miniaturization of all end applications and extended battery life. The solutions provided by the CEM102 and RSL15 platform help engineers create compact, resilient, and cost-effective connected products, such as healthcare devices, that can enhance blood glucose regulation, reduce diabetes-related risks, and integrate seamlessly into our lives.
For over 20 years, onsemi has played a key role in developing technology that supports and powers remote healthcare devices. With its advanced in-house packaging technology and FDA-compliant manufacturing techniques, onsemi leads in developing tiny system-in-package (SiP) solutions. onsemi also has extensive experience in developing ultra-low-power solutions for monitoring and treating various common diseases, such as hearing aids, pulse oximeters for measuring blood oxygen levels, electrocardiograms (ECGs), and blood glucose monitors. Despite the different types of diseases, the technologies used are highly similar, with key requirements such as ultra-low-level signal sensing, signal processing, control, and secure connectivity.
These devices primarily connect using protocols such as Bluetooth® Low Energy, which enables wider connectivity through smartphones. With advancements in BLE protocols and the introduction of onsemi’s innovative devices, wearable devices and other small medical devices can operate for up to a decade without needing a battery replacement.
Comprehensive and user-friendly electrochemical sensing application development platform
The RSL15, launched by onsemi, is an ultra-low-power, secure, low-power Bluetooth 5.2 wireless MCU based on the Arm® Cortex®-M33 processor, designed for smart connected devices in industrial and medical applications. The RSL15 features built-in power management, a wide power voltage range, flexible GPIO and clocking scheme, and an extensive set of peripherals, providing maximum design flexibility for high-performance and ultra-low-power applications. The RSL15 includes 80kB of RAM and offers two flash memory options: 284kB or 512kB.
onsemi also introduced a software development kit (SDK) paired with the RSL15, which is comprehensive and user-friendly. It includes drivers, libraries, sample code, development tools, and mobile apps (RSL Central for iOS® and Android™, as well as RSL FOTA for iOS and Android). The development environment includes onsemi IDE, Keil μVision®, and IAR Embedded Workbench®.
On the other hand, the CEM102, an electrochemical sensor AFE launched by onsemi, is an analog front-end (AFE) specifically developed for continuous glucose monitoring (CGM) and other applications that use amperometric measurements, requiring the sensing of extremely low currents. With its compact design and low power consumption, it can further miniaturize many end applications and extend battery life. The CEM102 is designed to be used with the onsemi RSL15, providing several additional system-level advantages, such as optimized system power consumption and voltage operation. This includes operating the system within a wide power voltage range of 1.3 to 3.6 V, typically using a single 1.5 V silver oxide battery or a 3 V coin cell battery.
Additionally, onsemi has launched a CEM102 evaluation board (CEM102-EVB) designed to evaluate the performance and functionality of the CEM102, as well as to develop, demonstrate, and debug software applications for this device. Besides the CEM102, it also includes the RSL15 and example code for setting up and using the CEM102 to perform measurements, which helps to jump start of system and firmware development.
The CEM102-EVB is a complete two-channel electrochemical measurement solution with flexible self-diagnostic, calibration, and production testing (with customer PCB). It supports self-measurement of electrode polarization voltage and calibration circuit deviations, featuring a TIA amplifier with internal and external feedback circuits, as well as settings for measurement accuracy, linearity, and dynamic range. It has low power consumption in both storage and working modes and can measure the power consumption in each mode.
Conclusion
Electrochemical sensors have a wide range of applications in healthcare, environmental monitoring, and industrial safety, and the versatility of this technology extends far beyond its current utilization. Moreover, the cutting-edge platforms launched by onsemi are also crucial for advancing scientific research and discovering new applications. onsemi's CEM102 + RSL15 product portfolio and development platform will accelerate the product development process for healthcare product developers and serve as an ideal solution for developing related products.
