Farm Data Relay System

In loving memory of Gay Holman, an extraordinary woman.

The Farm Data Relay System is an easy way to link remote sensors to the internet without the need for WiFi. It uses the ESP-NOW protocol on widely available ESP32 and ESP8266 microcontroller boards, and can be used to collect and transmit sensor data in situations where it would be too difficult or energy-consuming to provide full WiFi coverage.

Using an assigned MAC address scheme allows for the whole system to be configured by setting just a handful of values in code. Every ESP-NOW gateway is assigned a single-byte identifier, known as the UNIT_MAC. This, along with a set 5-byte preamble, is assigned to the MAC address of the ESP at boot.

Gateways can be configured to send an ESP-NOW transmission either to the serial port using JSON, another ESP-NOW gateway, or broadcast it via LoRa PHY. An incoming transmission from the serial port can also be routed to the same interfaces, with the addition of MQTT.

Getting Started

To use FDRS with Node-Red and MQTT you'll need two ESP devices (gateways) that are connected via UART, plus additional ESP devices with sensors connected. The two gateways are programmed using the instructions found with the Gateway2000 sketch. The sensors can either use the example sketches included, or you can use the “fdrs_sensor.h” file to use FDRS with a sketch you’ve already written.

Sensors

typedef struct DataReading {
  float d;
  uint16_t id;
  uint8_t t;
} DataReading;

Each sensor in the system sends its data over ESP-NOW as a float 'd' inside of a structure called a DataReading. Its global sensor address is represented by an integer 'id', and each type is represented by a single byte 't'. If sensors need to send multiple types of readings (ex: temp and humidity), then they are sent in an array of DataReadings. A single DataReading.id may have multiple readings of different types associated with it.

Thank you

...very much for checking out my project! I truly appreciate everyone across the net who has reached out with assistance and encouragement. If you have any questions, comments, or issues please feel free to contact me at bogner1@gmail.com.

If you have any extra money laying around, you could send it to me via this Paypal link. I'm a farmer by occupation, and donations would help me to spend more time developing farm gadgets over the winter months.

A big thank you to both Sola Gratia Farm and The IDEA Store of Urbana, IL, USA, without whom this project would not exist.

A huge thanks to the ever-instructional Andreas Spiess.

Random Nerd Tutorials is also an indispensable source of ESP knowledge.