RFM95-LoRa-Wireless-Comm

Sender and Receiver code for the RFM95 LoRa wireless communication.

LoRa Documentation

RadioHead

Using more than three radios

If wanting to use more than three radios you have to modify

lib\RadioHead-1.130\RadioHead{radio class}.cpp

and

lib\RadioHead-1.130\RadioHead{radio class}.h

Also, you might have to find where it is saved locally on your system and modify it there, I haven't been able to test if that is required

In {radio class}.cpp file you add another index to _deviceForInterrupt, where N is the number after the previous, and add

else if(_myInterruptIndex == N)
  attachInterrupt(interruptNumber, isrN, RISING);

void RH_INTERRUPT_ATTR RH_RF95::isrN()
{
    if (_deviceForInterrupt[N])
	_deviceForInterrupt[N]->handleInterrupt();
}

In {radio class}.h declare and add 1 to RH_RF95_NUM_INTERRUPTS

#define RH_RF95_NUM_INTERRUPTS = N
static void         isrN();

Supposedly they had it set up like this because most Arduinos can only handle two and MEGAs can only handle three, but we move different

Pins for Teensy 4.0

-- CS pins can be on any logic pin, currently using pins defined as CS pins by Teensy -- Chained pins can theoretically go infinitely, just limited by logic pins but check warning above to implement in code

Breadboard Pins (Reciver)

Teensy ----> LoRa 0 ----> LoRa 1 ----> LoRa 2 ----> LoRa 3

5v ----> power rail ----> (LoRa 0) VIN ----> (LoRa 1) VIN ----> (LoRa 2) VIN ----> (LoRa 3) VIN

13 ----> (LoRa 0) SCK ----> (LoRa 1) SCK ----> (LoRa 2) SCK ----> (LoRa 3) SCK

GND ----> (LoRa 0) GND ----> (LoRa 1) GND ----> (LoRa 2) GND ----> (LoRa 3) GND

38 ----> (LoRa 0) CS

37 ----> (LoRa 1) CS

36 ----> (LoRa 2) CS

10 ----> (LoRa 3) CS

21 ----> (LoRa 0) G0

20 ----> (LoRa 1) G0

19 ----> (LoRa 2) G0

18 ----> (LoRa 3) G0

11 ----> (LoRa 0) MOSI ----> (LoRa 1) MOSI ----> (LoRa 2) MOSI ----> (LoRa 3) MOSI

12 ----> (LoRa 0) MISO ----> (LoRa 1) MISO ----> (LoRa 2) MISO ----> (LoRa 3) MISO

CAN ----> 5v !!!Only connect when powering through USB, not the car!!!

CAN ----> GND

CAN HIGH ----> 23

CAN LOW ----> 22

Protoboard Pins (Sender)

Note: While the pin is marked 5v, our CAN network supplies 3.3v so it wont be opperating at 5v

Teensy ----> LoRa 0 ----> LoRa 1 ----> LoRa 2 ----> LoRa 3

JSTX 3.3v ----> 5v ----> (LoRa 0) VIN ----> VIN ----> VIN ----> VIN

JSTX GND ----> GND ----> (LoRa 0) GND ----> GND ----> GND ----> GND

JSTX CAN HIGH ----> 23

JSTX CAN LOW ----> 22

13 ----> (LoRa 0) SCK ----> SCK ----> SCK ----> SCK

10 ----> (LoRa 0) CS

  9 ----> (LoRa 1) CS

  7 ----> (LoRa 2) CS

  6 ----> (LoRa 3) CS

21 ----> (LoRa 0) G0

20 ----> (LoRa 1) G0

19 ----> (LoRa 2) G0

18 ----> (LoRa 3) G0

11 ----> (LoRa 0) MOSI ----> (LoRa 1) MOSI ----> (LoRa 2) MOSI ----> (LoRa 3) MOSI

12 ----> (LoRa 0) MISO ----> (LoRa 1) MISO ----> (LoRa 2) MISO ----> (LoRa 3) MISO

Teensy 4.0 Spec Sheet