How do remote temperature and humidity sensors work?

Within a lab setting, it’s important to ensure that any materials such as biological samples and pharmaceuticals are stored properly. Cold storage monitoring doesn’t just mean keeping invaluable materials safe and secure, only accessible by qualified and responsible personnel—it also means maintaining the right environment to protect these materials from degradation.

When it comes to cold storage, temperature and humidity are two essential conditions that must be monitored and maintained over time. Otherwise, entire studies can wind up compromised due to unusable materials. This type of situation is not only costly, but it could also set research and development projects back by days, weeks, months…even years. There are several types of wireless temperature and humidity sensor, which this article will explore (including examples).

What are remote temperature sensors?

Remote temperature sensors are wireless electronic devices that enable cold storage temperature monitoring without requiring manual effort on the part of lab personnel. Modern, IoT-enabled temperature sensors make it possible to easily check refrigerator or freezer temperatures from a wide range of personal device types, such as cell phones and tablets.

What are the types of temperature sensors?

Generally speaking, there are four main types of temperature sensors:

• Resistance temperature detectors (RTDs)
• Thermistors (negative temperature coefficient, or NTC)
• Thermocouples (such as our Element-T sensor)
• Semiconductor-based sensors

How do remote temperature sensors work?

First, a remote sensor device is installed within one or more cold storage areas or facilities. These small devices collect temperature data, often on a continuous basis, and transmit their readings to any number of connected devices via the cloud. 

In many cases, there will also be a cloud-based alerting and monitoring platform that can be configured to send alerts or notifications in cases where temperatures fall out of set thresholds. This way, conditions can be addressed in a timely manner, preserving the viability of stored materials. 

What is a humidity sensor?

Similar to temperature sensors, a humidity sensor is a small, electronic device that measures environmental humidity. In the case of a remote humidity sensor, wireless/cloud functionality is included—meaning the results can similarly be monitored easily via a cell phone, tablet, or other device.

How do humidity sensors work?

A humidity sensor’s basic working principle is simple, though perhaps a little more complex than that of a temperature sensor. While there are a few different types of humidity sensors, each type works by detecting environmental changes, such as altered electrical currents or fluctuations in the surrounding air’s temperature. Based on what the sensor detects, it outputs either absolute or relative humidity readings (depending on the type of sensor).

What are the three humidity sensor types?

The three most common types of humidity sensors are capacitive, resistive, and thermal conductivity. One major difference between these types is that the first two measure relative humidity while the third measures absolute humidity. Since they’re a little more complex than temperature sensors, let’s take a quick look at how each of these sensor types actually works.

How do capacitive humidity sensors work? 

Capacitive humidity sensors output relative humidity readings based on the electrical capacitance (or a material’s capacity to store an electric charge) that occurs between the sensor’s metal electrodes. 

How do resistive humidity sensors work? 

Also sometimes referred to as electrical conductivity sensors, the resistive humidity sensor working principle is similar to that of a capacitive humidity sensor, in that it derives measurements from a pair of electrodes within a probe that’s connected to the sensor. Unlike capacitive sensors, resistive humidity sensors’ readings are based on changes in resistivity between the probe’s electrodes.

How do thermal conductivity humidity sensors work? 

The final type of humidity sensor measures absolute humidity (rather than relative humidity). As an electrical current passes between two thermistors, they begin to self-heat. When one thermistor is then exposed to more humid air, the difference in resistance between the two correlates with absolute humidity levels.

What is the best way to monitor cold storage temperature and humidity levels?

Getting the right types of remote temperature and humidity sensors in place is just one piece of the larger LabOps puzzle. Keeping an eye on temperatures and humidity levels within a cold storage facility (or anywhere along the “cold chain”) is only really as useful as it is actionable. Developing an effective temperature and humidity monitoring system means answering a few important questions, such as:

• What temperature and humidity levels need to be maintained, and what are the consequences if materials are subject to non-ideal conditions?
• What types of remote temperature and humidity sensors will work best within a particular facility or with a certain type of biomaterial?
• What kinds of devices and applications do remote temperature and humidity sensors need to be compatible with?
• How could the organization benefit from an actionable LabOps platform that enables remote temperature and humidity monitoring with configurable alerts?

If you’re asking yourself any of the above questions, Elemental Machines has a solution that’s ready to be tailored to your specific needs. We provide a comprehensive LabOps platform consisting of software and hardware elements that work together seamlessly, integrate easily with other systems, power custom dashboards for effective temperature and humidity monitoring, and more.

Learn more about how you can get started with our platform today, including how it works and its wide range of applications.