The article explores the advantages of wearable technology for accurate temperature measurements, highlighting their benefits over traditional methods and discussing the advancements offered by infrared thermometers.

At the right time, a patient's temperature can tell about their health and help healthcare professionals make important decisions while treating their sickness. Temperature readings can be useful for tracking the development of sickness and identifying potential infections. Additionally, it can also assess the efficacy of treatments.

What are the shortcomings of conventional methods used to measure body temperature?

It is well-known that human body temperature can be measured in three ways: rectal, oral, and axillary. Nevertheless, there are drawbacks to each approach when it comes to taking the measures. Oral thermometers may break a bit, rectal thermometers can irritate the rectum, and long periods of holding the thermometer still cannot give a reliable reading. 

For this reason, two types of thermometers were developed: one for taking the temperature of the eardrum and another for taking the temperature of the entire body, which is put on the subject's forehead. Unlike traditional oral, rectal, and axillary thermometers that use mercurial or platinum resistance to measure temperature, both approaches use infrared sensors. 

Recent studies have utilized a variety of electrical devices to measure skin properties, such as electrical impedance, objectively. At the same time, many people in the medical field are trying to figure out how to monitor core body temperature without intrusive procedures by determining the correlation between skin temperature and core body temperature. 

Advantages of Infrared Thermometer Over Conventional Thermometers

The infrared thermometer is convenient for measuring surface temperatures. These devices detect and quantify various objects' infrared radiation emissions. It is small, light, and easy to operate. The two most common methods for taking a patient's temperature are:

  • Point thermometers 
  • Contactless infrared cameras

Contactless Infrared Point Thermometers

Many rely on contactless infrared point thermometers for a quick, safe, harmless, and non-interactive reading of core body temperature. Many infrared point thermometers, also known as infrared contactless thermal guns, are available today. These devices are identical in terms of price and software/hardware compatibility. 

Key Components

The typical components of a contactless infrared point thermometer are:

  • Lens
  • Detector
  • Signal amplifier
  • Digital signal processing source

In addition, many parts of the body can have their temperature measured using these instruments. Most people have their foreheads measured. Contactless infrared point thermometers only have one thermal detector; hence, they only provide one temperature reading.

Contactless Infrared Cameras

Infrared cameras employ a grid of thermal detectors to create a two-dimensional map of temperatures. On the other hand, The main concern with these non-contact infrared thermometers is not the cost but the reliability of the measurements. 

Challenges

Researchers defined several factors as influencing body temperature measurement, including:

  • The emissivity and reflection coefficient of the emitting skin surface
  • The transmission coefficient of the medium between the sensor and the target
  • The average radiant temperature of the measurement environment 
  • The distance and size of the target 
  • Instrumental uncertainties 
  • Operator's ability 

The Concept of ‘Semiconductor Sensor-Based Wireless Health Monitoring System’

This article presents a wireless health monitoring device that measures core body temperature using semiconductor sensors. The suggested wireless temperature-measuring device, as shown in Fig. 1, differs from other methods in that it is attached to the skin surface of the back, just below the neck. 

Fig. 1 Proposed wireless health monitoring system. Source: HINDAWI

Advantages

This area has relatively thin layers of fat and muscle thus, the skin temperature here is more indicative of the core body temperature. This spot is also great for securing the gadget to the body so that it stays for longer periods of time. 

The wireless temperature-measuring device for skin temperature measurements has:

Key Components

The general outline of the proposed wireless health monitoring system, which consists of two components: 

  • A transmitter that measures skin temperature through wireless means
  • A receiver receives the data from the transmitter and transmits it to a computer for storage and display

Sensor

The researcher of the wireless thermometer chose the Si7021, a semiconductor-based micro temperature sensor, to track the user's core body temperature. This sensor accurately measures skin temperature with low power consumption and has a modest measurement error of about ±0.4°C at a 1 Hz sample rate for temperature measurement.

Microprocessor

The EFM32WG 32-bit microprocessor is built on the ARM Cortex-M4 platform. It is also suited for real-time core body temperature estimation by embedding the algorithm due to its up to 256 kB flash memory, 32 kB RAM, and CPU speeds of up to 48 MHz. This microcontroller unit can manage the device with good efficiency, extended battery, and reduced energy consumption. 

Transceiver

The nRF24L01 transceiver was selected for this study so that the transmitter and receiver could communicate wirelessly.

Receiver

The C8051F996 microcontroller unit was selected for the receiver's control throughout its creation. 

Conclusion

Results from the performance tests showed that the gadget was accurate in its temperature readings taken in a controlled environment. Additionally, the suggested gadget has a 40-hour continuous runtime and power consumption of about 5.99 mA while operating. Hence, the suggested gadget can be safely fastened to the back of the body to provide long-term accurate skin temperature measurement. 

According to an experiment with 10 volunteers in the rest status, the skin temperature is lower than the ear temperature. By utilizing the algorithm that was created, the difference was filled, and the skin temperature, which was used to estimate the core body temperature, came very near to matching the ear temperature.

Summarizing the Key Points

  • Wearable devices revolutionize healthcare by enabling accurate body temperature monitoring for informed decision-making and treatment efficacy assessment
  • Contactless infrared point thermometers offer quick, safe temperature readings, enhancing healthcare monitoring efficiency
  • Infrared cameras provide detailed temperature maps, although the reliability of measurements remains a concern
  • Semiconductor-based health monitoring systems offer accurate core body temperature tracking, improving healthcare outcomes

Reference

Piccinini, Filippo, Giovanni Martinelli, and Antonella Carbonaro. “Reliability of Body Temperature Measurements Obtained with Contactless Infrared Point Thermometers Commonly Used during the COVID-19 Pandemic.” Sensors 21, no. 11 (May 30, 2021): 3794.
https://doi.org/10.3390/s21113794

Wei, Qun, Hee-Joon Park, and Jyung Hyun Lee. “Development of a Wireless Health Monitoring System for Measuring Core Body Temperature from the Back of the Body.” Journal of Healthcare Engineering 2019 (February 17, 2019): 1–8.
https://doi.org/10.1155/2019/8936121