Farm data relay system: combine LoRa and 2.4 Ghz networks without WiFi routers or cloud dependency

Setting up a wireless sensor network over a wide area can quickly get expensive, and getting everything to communicate smoothly can be a huge headache, especially when you combine Wi-Fi with short range with long range LoRa. To simplify this, [Timm Bogner] created Farm Data Relay System which simplifies the process of combining LoRa, 2.4 Ghz modules and serial communications in various topologies over large areas.

FDRS uses a combination of ESP32/8266 sensor nodes for short range and LoRa nodes for long range. ESP nodes use Espressif's connectionless ESP-NOW peer-to-peer protocol over which multiple ESP boards can communicate directly without the need for a Wi-Fi router. ESP modules can have one of 3 roles, nodes, repeaters or gateways, and gateways and repeaters share the same code. Nodes accept sensor input and are configured to each have a unique READING_ID.

Relays simply retransmit ESP-NOW packets to extend network range, while gateways convert packets between ESP-NOW, MQTT over Wi-Fi, LoRa, or serial messages as needed. Repeaters and gateways each have a unique UNIT_MAC for addressing. The code that handles communication for ESP devices is simple and well documented, so all you need to do is set a few configuration values, and then you can focus your efforts on the code required for your specific application.

The hub of the system is a Raspberry Pi running Node-RED which acts as the final MQTT Gateway and connects to ESP MQTT Gateways. This means that all the action takes place in the local network, without depending on an Internet connection and a cloud service. However, it can still send and receive data over the Internet using MQTT or any other protocol as needed. Node-RED makes it especially easy to create custom automations and interfaces.

In the video after the break, Andreas Spiess, the man with the Swiss accent, who also took part in the project, goes over all the features, configuration and caveats.

LoRa is an extremely useful tool for long-range outdoor networks. From monitoring birdhouses without the internet, to texting without cellular networks, and even sending signals back to the moon, the uses are endless.