At Mapsens® we gather and analyze data from different sources (drones, weather stations, satellite…) to obtain useful information, in order to offer a comprehensive crop monitoring to our customers. Although this information in itself is valuable, having access to real-time ground measurements opens up a range of interesting possibilities, especially to create early warnings or to get a better control of crop irrigation.
To offer these possibilities within Mapsens® we have decided to develop our own sensors. These sensors measure relative air humidity, ambient temperature and soil moisture at two depths and transmit the data in real time to the server using IoT technology. The design has been carried out with the idea of offering a product that is low cost, while maintaining a commitment to quality, to allow monitoring a crop with a reasonable investment.
The major obstacle to achieve such a device is the power consumption, since they have to operate autonomously for long periods of time over a large area of land. To solve this problem, we first took advantage of LPWAN technology, through the Sigfox operator. This allows communications with very low power consumption. Even so, we have incorporated a solar panel into the sensor, thus avoiding the inconvenience and cost of having to change the batteries in the sensor network on a regular basis.
The device has an ambient temperature and relative humidity sensor. This sensor has an accuracy of ±0.5ºC and ±4% relative humidity. Capacitive sensors are used to measure soil moisture, which offer good characteristics and durability in relation to their price. The built-in sensors have been chosen to be resistant to the environmental conditions of the soil without deteriorating their performance over time.
Sigfox can send data with a frequency of up to 10 messages per minute. However, the device samples the most frequent variables, filtering these signals before transmitting them for more reliable measurements. After this process the data is stored on our servers where it is processed, an alarm is created if necessary and made available to the customer.
Air temperature and humidity sensor measurement display.
Visualization of measurements from soil moisture sensors.
In short, we have an economical, autonomous sensor that provides Mapsens® with an immediate response to threats and continuous monitoring of crops. It also provides, in the long run, a data history that can be combined with the other sources of information available to us, complementing the analyses that can be carried out.
