What Is a Wireless Temperature Sensor?
A wireless temperature sensor is a device that measures temperatures, such as those in pipelines, without the need for wired connections like power cables.
Traditional wired temperature sensors often require long power cables and can have installation limitations. Wireless temperature sensors eliminate these restrictions, allowing for installation in desired locations. They are used in industrial applications for monitoring pipeline temperatures, internal concrete temperatures, and other temperature-related monitoring. Additionally, they are used in educational settings for science experiments. The power sources are mainly divided into battery-powered and self-powered types.
Uses of Wireless Temperature Sensors
The primary use of wireless temperature sensors is for temperature monitoring in industrial applications. Main uses include:
- Measuring pipeline temperatures
- Monitoring machinery conditions (e.g., pumps, motors, compressors, gearboxes in process industries and semiconductor plants)
- Measuring internal concrete temperatures
- Temperature monitoring in retail and food industries (e.g., supermarkets, greenhouses, cold storage rooms, aquaculture facilities, refrigerated trucks)
Specifically, pipeline temperature and machinery condition monitoring are applicable in a wide range of industries such as power plants, chemical plants, oil refineries, and food processing facilities.
Wireless temperature sensors are also utilized in educational settings. Temperature-related science topics are covered from elementary to high school levels, allowing for various uses. They are employed in various experiments, including supercooling, distillation, and heat of neutralization, and waterproof models can be used outdoors.
Principle of Wireless Temperature Sensors
Measurement Mechanism
Wireless temperature sensors detect temperatures using common temperature sensors like thermocouples, thermistors, and resistance temperature detectors (RTDs). A thermocouple is a temperature sensor that uses the electromotive force generated by connecting two different metals with a temperature difference. Thermistors and RTDs measure temperature by correlating material resistance with temperature.
Thermistors are characterized by their ability to measure narrow temperature ranges with high sensitivity and small size, while RTDs cover wide temperature ranges with good linearity but lower sensitivity than thermistors. There are two types of thermistors: NTC thermistors, which decrease in resistance linearly with temperature increase, and PTC thermistors, which increase in resistance non-linearly with temperature increase. Common materials used are semiconductor ceramics primarily composed of metal oxides such as nickel, cobalt, manganese, and iron. RTDs mainly use platinum, nickel, and copper.
Power Source
Wireless temperature sensors come in battery-powered and self-powered or energy-harvesting types. Battery-powered types use various batteries like CR2032 button cells, AA, AAA, and lithium batteries.
Self-powered types do not require batteries and operate by collecting waste energy from surrounding heat, vibration, etc. Energy sources include temperature differences, vibrations, sunlight, and magnetic fields. This eliminates the need for battery maintenance and reduces operational costs.
Data Transmission
Wireless temperature sensors use various wireless communication methods for data transmission to data loggers, such as Wi-Fi, Zigbee, Lora, LoRaWAN, and Bluetooth. The suitable data communication method is chosen depending on the product and application. For instance, LoRaWAN offers excellent reception sensitivity and resistance to radio interference, allowing for communication distances of over 10 km in ideal environments, making it suitable for wide-area operations.
Types of Wireless Temperature Sensors
Wireless temperature sensors come in various types, as mentioned earlier. They are categorized based on application, such as industrial pipeline measurement, machinery measurement, and scientific experiments in educational institutions.
The temperature measurement range varies by product, so selecting the appropriate one is necessary. Measurement intervals also vary by product, and some offer real-time data display. Products with IP66/IP67 waterproof ratings can be used in wet environments or outdoors.
Moreover, some products have explosion-proof certification, allowing installation in hazardous areas handling flammable gases, such as petrochemical plants, paint factories, and chemical plants.