From 3a58de2863bfc43b8ce2050c72b06c92bd54a587 Mon Sep 17 00:00:00 2001
From: franchioping <franchioping@gmail.com>
Date: Fri, 14 Jun 2024 21:08:28 +0100
Subject: [PATCH] Add Receiver Code

Signed-off-by: franchioping <franchioping@gmail.com>
---
 recv/recv.ino | 148 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 recv/recv.ino

diff --git a/recv/recv.ino b/recv/recv.ino
new file mode 100644
index 0000000..2910912
--- /dev/null
+++ b/recv/recv.ino
@@ -0,0 +1,148 @@
+#include <RFM69.h>    
+
+#define NODEID      1
+#define NETWORKID   100 // Change to a less common value on the day    
+#define GATEWAYID   1   // As a rule of thumb the gateway ID should always be 1. Doesn't do anything here but kept for symmetry
+
+// Both have to be the same
+#define FREQUENCY     RF69_433MHZ
+
+
+// Listen in on packets even if they weren't meant for us
+bool spy = true;
+
+RFM69 radio;
+
+/*
+  Transmission data. This struct is and has to be the same on both sides of the communication.
+  If they aren't the same, code will fallback to printing the data as a string so it can be recovered later
+*/
+typedef struct transData {
+  float temperature;
+  float pressure;
+  unsigned long time;
+} transData;
+
+// Initialize our Data Structure. we write over it every time to avoid mallocing memory repeatedly
+transData theData;
+
+/*
+  Inspired By:
+
+  HOW TO RESET AN ARDUINO USING CODE: SOFTWARE RESET
+  By: TheGeekPub.com
+  More Arduino Tutorials: https://www.thegeekpub.com/arduino-tutorials/
+
+
+  Not tested, should crash and then reset the board.
+  Would just wire a pin to the reset pin but wasn't allowed.
+*/
+void(* resetFunc) (void) = 0; 
+
+
+void setup() {
+  // Initialze Serial
+  Serial.begin(9600);
+
+  /*  
+    Set Chip-Select pin for the radio.
+    The RF69 uses the SPI interface for communication so each chip requires its own chip-select
+  */
+  radio.setCS(10);
+
+  /*
+    Set the Interrupt pin for the radio - Connected to DIO0 (Digital IO 0).
+    This pin is programmed as an interrupt for recieving data by the RFM69 library
+
+    All other interrupts are programatically disabled so we only need to set this one
+  */
+  radio.setIrq(3);
+
+  /*
+    Initializes radio and returns 1 if it is successful
+  */
+  bool sucess = radio.initialize(FREQUENCY,NODEID,NETWORKID);
+  radio.setHighPower();
+
+  Serial.print("RADIO INITIALIZE: ");
+  Serial.println(sucess);
+
+  /*
+    Check if radio was initialized correctly. If not, try to reset the arduino
+  */
+  if(sucess == 0){
+    Serial.println("Couln't initialize radio, hard reseting...");
+    delay(200);  
+    resetFunc();
+  
+  }
+
+}
+
+void loop() {
+
+  /*
+    RFM69::receiveDone() returns true if we have data ready to be read
+    data is located at radio.DATA with lenght radio.DATALEN
+
+
+    All the data recieved is just printed out to the serial. Would love to keep it on an SD card but wasn't allowed
+  */
+  if(radio.receiveDone()){
+
+    /* ===== Pretty printing ===== */
+    Serial.print('[');Serial.print(radio.SENDERID, DEC);Serial.print("] ");
+
+    // RSSI is the signal strenght, signals if there is a good connection - Higher is Better
+    Serial.print(" [RX_RSSI:");Serial.print(radio.readRSSI());Serial.print("]");
+
+    /*
+      We can detect all packets in the network, even if they aren't addressed to us
+      Do this by default, 
+    */
+    if (spy) Serial.print("to [");Serial.print(radio.TARGETID, DEC);Serial.print("] ");
+
+    /*
+      If the data we receive isn't the size we expect, warn us about it
+    */
+    if (radio.DATALEN != sizeof(transData)){
+      Serial.print("Invalid packet received, lenght not matching expected struct!");
+
+      /*
+        Even if the payload isnt what we expect, print it as a string just in case
+        if something goes wrong this is here so we still have SOME data
+
+        Allocates a new chunk of memory with the data lenght + 1 so we can append a NULL at the end and treat it as a string
+      */
+      char* data_string = (char*) malloc(radio.DATALEN+1);
+      if(data_string != NULL){
+        memcpy(data_string, radio)
+        data_string[radio.DATALEN] = '\0';
+
+        Serial.println(data_string);
+      }else{
+        Serial.print("Failed to malloc string, not printing the packet");
+      }
+    }
+    else{
+      /*
+        Assume radio.DATA actually contains our struct and not something else of the same lenght.
+        Could be fixed by adding magic digits at the beggining/end but because of struct alignment that would
+        be really inefficient in terms of data size and for performance reasons we want our structs to be aligned
+      */
+
+      /*
+        Printing like this SHOULD allow us to graph the data later.
+        uptime is included to help with data analasys
+      */
+      theData = *(transData*) radio.DATA;
+      Serial.print(" temperature=");
+      Serial.print(theData.temperature);
+      Serial.print(" pressure=");
+      Serial.print(theData.pressure);
+      Serial.print(" time=");
+      Serial.print(theData.time);
+    }
+    Serial.println(".");
+  }
+}