Designed by Seeed Studio, with community contributors

Original project on Flux: https://www.flux.ai/seeedstudio/the-green-dot-2040e5-board~i2

WHAT IS THIS PROJECT ABOUT?

The Green Dot 2040E5 is a sensor node board that reads RS485 sensor probes and logs the data to the cloud over LoRa. It was published on Flux by Seeed Studio, with contributors listed on the project including jharwinbarrozo, collinsemasi and janeyang. It combines two Seeed Studio modules: the XIAO RP2040 and the LoRa-E5, which is based on the STM32WLE5JC. It also has strong power management, including solar charging and battery protection, which makes it a good fit for remote IoT applications.

The design has been popular on Flux since it was published in late 2023, with 35 stars and more than 45 forks, which shows how many people have used it as a starting point.

WHY THIS COMBINATION?

Many real-world sensors, especially industrial and agricultural probes, communicate over RS485, a robust differential serial bus that works well over long cables. LoRa is a long-range, low-power radio technology that is well suited to sending small packets of data across fields, farms, buildings and campuses. This board joins the two: it listens to RS485 probes on one side and reports over LoRa on the other.

The two modules each bring something specific. The XIAO RP2040 is a thumb-sized board (20 x 17.5 mm) with a dual-core RP2040 processor running up to 133 MHz, 264 KB of SRAM and 2 MB of on-board flash. The LoRa-E5 is a LoRaWAN transceiver module built around the STM32WLE5JC, available in 868 MHz and 915 MHz versions. An antenna is not included with the module.

Because the node is meant to run unattended, the board adds solar charging and battery protection, so it can keep itself powered outdoors and protect its battery from damage.

HARDWARE DESIGN

• Main controller module: Seeed Studio XIAO RP2040
• LoRa module: Seeed Studio LoRa-E5 (STM32WLE5JC), LoRaWAN, 868 MHz or 915 MHz versions
• Sensor interface: RS485 for industrial sensor probes
• Power: solar charging and battery protection
• Board construction: four-layer (top, two inner layers, bottom)

• Note: choose the LoRa module version and antenna that match the frequency band allowed in your region.

APPLICATIONS

Soil and environmental monitoring, agriculture and greenhouse sensing, remote weather and water-level stations, smart buildings, and any IoT project that needs a battery or solar-powered node reporting over long distances.

MANUFACTURING FILES

The project is published ready for fabrication and assembly. It includes a complete Gerber set covering top, bottom and both inner copper layers, solder mask, solder paste, silkscreen and board outline, together with an Excellon drill file, an IPC-D-356 electrical test netlist and a pick-and-place CSV for automated assembly. Bills of materials are provided in formats prepared for several manufacturers, including a version optimised for PCBWay.

CREDITS

Designed by Seeed Studio (Flux), with contributors listed on Flux including jharwinbarrozo, collinsemasi and janeyang. XIAO and LoRa-E5 are Seeed Studio products. All design work and credit belong to the original creators. Please visit the original Flux project, explore the design in full, and show the creators some support.