The adoption of LoRa-based solutions is growing every year. As the LoRaWAN infrastructure is slowly maturing and offering proper coverage in larger areas, the number of hardware manufacturers available to pick from has also increased.
The plethora of different options can be overwhelming for the end user. A simple Google search for the keywords "temperature LoRa sensor" will give you a glimpse of the market study one needs to run before buying a new device.
How to select a suitable sensor in these conditions?
Why are some devices more expensive than others for the same type of measurements?
In this article, we will give you some insights on what to consider when selecting a LoRa device.
The first and probably most important point is that there is no “one size fits all” in the world of LoRa sensors. The requirements and particularities of your use case will always dictate the choice of the sensor. In other words, you cannot buy a temperature & humidity sensor and expect to use it in all IoT applications. Hence, it is imperative to have a clear understanding of the requirements of your project before purchasing anything (minimal measurement precision, frequency of the messages, on-site access to the device).
A straightforward example is the choice of indoor vs. outdoor sensors. If your deployment needs to operate outdoors, you might want to choose a sensor clearly labeled for outdoor applications.These tend to have more robust packaging and a certain degree of waterproofing.
Now that this is out of the way, let’s explore all the other aspects to consider.
The device's technical characteristics and overall performance are obviously of great importance. You want to choose a device that delivers the accuracy needed for your particular applications. Ask yourself how precise your data needs to be and adjust your choice accordingly.
Be sure to verify which frequency plans are supported by the device and that it matches the regulations in your country. European countries typically operate at 863 - 873 MHz and 433.05 - 434.79 MHz, see a detailed list of the frequency plans by country here.
If you want to go the extra mile, you can check the LoRa device's internal components, particularly the sensing unit and make sure they come from a reputable manufacturer.
Certification plays a role as well. It is important to make sure that the device complies with the CE certification, which ensures that the radio and electrical design of the product follow specific rules and good practices.
However, nothing beats a direct assessment of the sensor on the field. Before rolling out a solution composed of many devices, it is usually good practice to order one unit and test it against a reference. By doing so, you will build your own experience with the sensor and see if the reality matches the expectations.
Good technical documentation is an element that is often overlooked when buying new hardware. However, a detailed and reader-friendly documentation is what makes the difference between smooth commissioning and long cycles of trial and error.
The question of the power supply is also decisive. Are you opting for an external power supply or a battery?
LoRa devices can run on batteries for up to 10 years, depending on different factors like signal quality and sending interval. But there will always be a time when you need to change the battery. And you need to take this into account in your solution lifecycle management. For some devices, access to the battery can be a bit tricky. In some rare cases, we even saw batteries being soldered directly on the board. That is a situation you might want to avoid.
An interesting alternative to standard batteries is the use of solar panels to power LoRa devices. When the environment allows it (enough ambient light during the day), these devices can be used to solve the question of the maintenance of the battery completely.
Many LoRa devices require some degree of calibration or configuration. The use of downlink messages or a dedicated smartphone app (via BLE or NFC) is then required to set up those devices. Hence, the complexity of the process can vary.
If you are deploying a large-scale solution involving hundreds of devices, performing this configuration step during production can be possible. In this case, you will need to verify that the manufacturer supports this and under which conditions.
The aesthetic considerations will, in some cases, play a significant role. If your solution is exposed to the public, a smart building case in a bank for example, your customer might be sensitive to the device's design. And, believe me, there is room for improvement on this topic.
This one is pretty straightforward. You want to select a device within your budget that displays the quality and performance your use case needs. The most expensive product might not be the best choice; it all depends on your use case.
The akenza Device Type Library hosts an extensive list of LoRa devices. It eases the registration of new devices into an IoT project by automatically taking care of the tedious work of payload parsing.
Our catalog offers a detailed description of the sensor's capabilities and measurement values for each device type. Therefore, it is a valuable reference to select the appropriate sensors for a particular use case and guide the purchase of new devices.