Using a pair of ESP32 Lora Modules as a pair of transponders.
Each module is programmed with the same code. Both begin by waiting a pre-determined amount of time, then initiate the link by sending a message, the correspond transponder then receives the message and acknowledges receipt with a return message and so the process repeats.
You can use this method; for example, to test range between two LoRa modules by taking one module away, perhaps battery powered and watching the on-board LED blink to denote it received a response from the other unit.
*** Use the same code on both units, maybe change the name of each unit accordingly ***
It is useful to name each transponder differently so they can be identified
Unit-1 name defined with: String deviceID = "Transponder-1";
Unit-2 name defined with: String deviceID = "Transponder-2";
The two units send a message to each other, monitor the serial port of each to see. The on-board LED blinks to denote reception of a LoRa packet
The transponder rate is set by the LED Blink time, set to 1000mS or 1-Sec
Make sure your pin assignments match the suppliers pin-outs.
#define LoRA_SCK 5
#define LoRA_MISO 19
#define LoRA_MOSI 27
#define LoRA_CS 18
#define LoRA_RST 14
#define LoRA_IRQ 26
e.g. find LoRa_IRQ on diagram in yellow, it's on GPIO-26 so use 26
Match pins defined in yellow with programme definitions:
