First Working version of the Emergengy pusher.

src/main.cpp

@@ -0,0 +1,199 @@
+#include <Arduino.h>
+#include <esp_now.h>
+#include <WiFi.h>
+ 
+// GPIOs
+#define GPIO_EMERGENCY_LED 5
+#define GPIO_SYNC_LED 19
+#define GPIO_EMERGENCY_BUTTON 16
+
+// Software Parameters
+#define LOOP_DELAY 1
+#define PING_TIMEOUT_NUM_LOOPS 2
+#define EMERGENCY_BUTTON_SCAN_RATE_SECONDS 2
+
+String macList[2] = {"24:6F:28:B1:EE:74", "24:6F:28:B2:40:8C"};
+String macLocal,macRemote;
+uint8_t macRemoteIntArr[6];
+esp_now_peer_info_t peerInfo={};
+int64_t lastPingUptimeInSeconds;
+volatile int64_t lastButtonPushUptimeInSeconds;
+boolean isReceiverEmergencyLedOn;
+volatile boolean isSenderEmergency;
+
+typedef struct struct_info {
+  boolean isEmergency;
+  boolean isPing;
+  String macOfSender;
+} struct_info;
+struct_info myData;
+
+
+int64_t getUptimeInSeconds(){
+  return esp_timer_get_time()/1000000;
+}
+
+// Callback when data is sent
+void OnDataSent(const uint8_t *mac_addr, esp_now_send_status_t status) {
+  Serial.print("\r\nLast Packet Send Status:\t");
+  Serial.println(status == ESP_NOW_SEND_SUCCESS ? "Delivery Success" : "Delivery Fail");
+}
+
+// Callback when data is received
+void OnDataRecv(const uint8_t * mac, const uint8_t *incomingData, int len) {
+  struct_info myData;
+  memcpy(&myData, incomingData, sizeof(incomingData));
+  Serial.print("Bytes received: ");
+  Serial.println(len);
+  Serial.printf("d:_%d_|",myData.isPing);
+
+  if (myData.isPing) {
+    lastPingUptimeInSeconds=getUptimeInSeconds();
+  } 
+
+  if(myData.isEmergency) {
+    digitalWrite(GPIO_EMERGENCY_LED,HIGH);
+    isReceiverEmergencyLedOn=true;
+  } else {
+    digitalWrite(GPIO_EMERGENCY_LED,LOW);
+    isReceiverEmergencyLedOn=false;
+  }
+}
+
+void OnButtonPushed(){
+  Serial.println("BUTTON PUSH CALLBACK.");
+  if((getUptimeInSeconds()-lastButtonPushUptimeInSeconds)>EMERGENCY_BUTTON_SCAN_RATE_SECONDS){
+    isSenderEmergency=!isSenderEmergency;
+    lastButtonPushUptimeInSeconds=getUptimeInSeconds();
+    Serial.println("BUTTON PUSH EXEC.");
+  }
+}
+
+int char2int(char input)
+{
+  if(input >= '0' && input <= '9')
+    return input - '0';
+  if(input >= 'A' && input <= 'F')
+    return input - 'A' + 10;
+  if(input >= 'a' && input <= 'f')
+    return input - 'a' + 10;
+  throw std::invalid_argument("Invalid input string");
+}
+
+// This function assumes src to be a zero terminated sanitized string with
+// an even number of [0-9a-f] characters, and target to be sufficiently large
+void hex2bin(const char* src, uint8_t* target)
+{
+  while(*src && src[1])
+  {
+    *(target++) = char2int(*src)*16 + char2int(src[1]);
+    src += 2;
+  }
+}
+
+void setup(){
+  sleep(LOOP_DELAY);  // give the serial monitor a moment to connect.
+  Serial.begin(115200);
+  WiFi.mode(WIFI_MODE_STA);
+  macLocal=WiFi.macAddress();
+  macRemote=macList[macList[0]==macLocal?1:0];
+  Serial.println("Local [" + macLocal + "] -> Remote: [" + macRemote+"]");
+
+  // Init ESP-NOW
+  if (esp_now_init() != ESP_OK) {
+    Serial.println("Error initializing ESP-NOW");
+    return;
+  }
+
+  // Once ESPNow is successfully Init, we will register for Send CB to
+  // get the status of Trasnmitted packet
+  esp_now_register_send_cb(OnDataSent);
+  
+  // Register peer
+  String macRemoteNoColon=macRemote;
+  macRemoteNoColon.replace(":","");
+  char macRemoteNoColonCharArr[13];
+  macRemoteNoColon.toCharArray(macRemoteNoColonCharArr,sizeof(macRemoteNoColonCharArr));
+  
+  for (int i=0;i<12;i++){
+    Serial.print( macRemoteNoColonCharArr[i]);
+    Serial.print(".");
+  }
+  Serial.println("<--- HEX CA");
+
+  hex2bin(macRemoteNoColonCharArr,macRemoteIntArr);
+  for (int i=0;i<6;i++){
+    Serial.printf( "%d|%X - ",macRemoteIntArr[i],macRemoteIntArr[i]);
+  }
+  Serial.println("<--- DEC REM");
+  memcpy(peerInfo.peer_addr, macRemoteIntArr, 6);
+  peerInfo.channel = 0;  
+  peerInfo.encrypt = false;
+  peerInfo.ifidx = WIFI_IF_STA;
+  
+  // Add peer        
+  if (esp_now_add_peer(&peerInfo) != ESP_OK){
+    Serial.println("Failed to add peer");
+    return;
+  } 
+  
+  // Register for a callback function that will be called when data is received
+  esp_now_register_recv_cb(OnDataRecv);
+
+  pinMode(GPIO_EMERGENCY_LED, OUTPUT);
+  digitalWrite(GPIO_EMERGENCY_LED,LOW);
+  pinMode(GPIO_SYNC_LED,OUTPUT);
+  digitalWrite(GPIO_SYNC_LED,LOW);
+
+  pinMode(GPIO_EMERGENCY_BUTTON,INPUT_PULLDOWN);
+  attachInterrupt(GPIO_EMERGENCY_BUTTON, OnButtonPushed, RISING);
+
+  myData.isPing=1;
+  myData.macOfSender="";
+  isReceiverEmergencyLedOn=false;
+  myData.isEmergency=false;
+  isSenderEmergency=false;
+  lastButtonPushUptimeInSeconds=getUptimeInSeconds();
+}
+ 
+void loop(){
+  // Send message via ESP-NOW
+  sleep(LOOP_DELAY);
+  boolean isButtonPushed = (HIGH== digitalRead(GPIO_EMERGENCY_BUTTON));
+  Serial.println(isButtonPushed?"PUSHED":"RELEASED");
+
+  // only one device has a button, the origin will tell the recipient to revert back the status.
+  if (isButtonPushed) {
+    myData.macOfSender=macLocal;
+  }
+
+  if (myData.macOfSender!=macLocal) {
+    myData.isEmergency=isReceiverEmergencyLedOn;
+  } else {
+    myData.isEmergency=isSenderEmergency;
+  }
+
+  esp_err_t result = esp_now_send(macRemoteIntArr,(uint8_t *) &myData, sizeof(myData));
+  
+  Serial.println(myData.isEmergency?"EMERGENGY ON":"EMERGENCY OFF");
+  Serial.println((isSenderEmergency==1)?"SEN EMERG ON":"SEN EMERG OFF");
+  
+
+  if ((getUptimeInSeconds()-lastPingUptimeInSeconds) < (LOOP_DELAY*PING_TIMEOUT_NUM_LOOPS)) {
+    digitalWrite(GPIO_SYNC_LED,HIGH);
+  } else {
+    digitalWrite(GPIO_SYNC_LED,LOW);
+  }
+
+  switch (result) {
+    case  ESP_OK:
+      Serial.println("[" +macLocal+ "] Sent with success");
+      break;
+    case ESP_ERR_ESPNOW_NOT_FOUND:
+      Serial.println("[" +macLocal+ "] Peer not Avavilable");
+      break;
+    default:
+      Serial.printf("[%s] Error sending the data [%X]\n",macLocal,result);
+  }
+  
+}