EKO-Nativas Outdoor Rugged Sensor -

The Problem

Monitoring remote environments where cellular data is not covered is a modern challenge a few people are trying to solve. This long distance communication is a great opportunity for initiatives like Nativas where reforestation plays a key role in safekeeping the environment. Modern communication standards require the use of certain frequencies and power outputs and certifications are required in order to use certain radio bands. For this modern technologies such as LoRa and Mesh Networking take center stage in this project as we aim to solve these problems.

Proposed Solution

Long distance communication can be achieved in two different ways. Mesh Networking is a network configuration that allows devices to talk to each other and re-send messages to the destination in a self-configuring self-healing network.

Certainly Mesh Networking would allow devices to form the network required for communication by themselves, but we'll also need to extend the node to node distance as much as possible. Here's where LoRa comes into the equation. LoRa is a wireless modulation technique derived from Chirp Spread Spectrum (CSS) technology. It encodes information on radio waves using chirp pulses enabling robust communication against disturbances and can be received across great distances.

Device Composition

The EKO-Nativas Devices are comprised of a PET-G canister that protects the interior electronics. Each device contains sensors capable of measuring soil humidity as well as ambient humidity and temperature, paramount variables in crops control. A CO2 concentration sensor was included for air quality measurement as well as a GSM Radio for connection to the Nativas Server. Power management units guarantee a long lasting battery life nurtured by the two solar panels which provide all energy the single 16500 cell needs for a self sustaining cycle

Operation

Depending on the terrain and sun availability units can last from months to even never requiring battery replacement for data reporting. The devices hibernate until the internal RTC, used to sync all network devices, send the wake up signal. Data measurement is then executed as the Mesh Network takes form in the whole terrain using LoRa modulation. All devices send their data through the network to the node designated as Bridge. The Bridge is the direct communication link to the Nativas Server using the MQTT Protocol, we can have multiple bridges at this stage. At the end the bridges send a broadcast signal with the RTC timestamp and the sleep time window enabling a time sync across the entire network. All devices hibernate until the next update cycle is triggered.

Physical Tests

Tests were performed on an open beach in Argentina with clear Line of Sight (LoS) between nodes at a height of 2 meters from the ground. The maximum node to node distance achieved so far was of 430m. Test result where replicated during subsequent tests across different days.

We believe results can be greatly increased by using different antennas or elevating the devices from the ground much more.

Discussion

This project is still ongoing and would like to start a discussion on how these kind of configuration might benefit different applications. If this kind of problem is the one that doesn't let you sleep at night feel free to comment or reach me for any inquiries, thank you for reading.