First commmit

.gitignore

+.pio
+.vscode/.browse.c_cpp.db*
+.vscode/c_cpp_properties.json
+.vscode/launch.json
+.vscode/ipch

.vscode/extensions.json

+{
+    // See http://go.microsoft.com/fwlink/?LinkId=827846
+    // for the documentation about the extensions.json format
+    "recommendations": [
+        "platformio.platformio-ide"
+    ],
+    "unwantedRecommendations": [
+        "ms-vscode.cpptools-extension-pack"
+    ]
+}

platformio.ini

+[env:esp32dev]
+    platform = espressif32
+    board = esp32dev
+    framework = arduino
+    lib_deps =
+        chris--a/Keypad@3.1.1
\ No newline at end of file

src/main.cpp

+#include <Keypad.h>
+
+#define ROW_NUM     4
+#define COLUMN_NUM  4
+#define LED_BUILTIN 2
+
+char keys[ROW_NUM][COLUMN_NUM] = {
+  {'1', '2', '3', 'A'},
+  {'4', '5', '6', 'B'},
+  {'7', '8', '9', 'C'},
+  {'*', '0', '#', 'D'}
+};
+
+byte pin_rows[ROW_NUM]      = {19, 18, 5, 17}; // GPIO19, GPIO18, GPIO5, GPIO17 connect to the row pins
+byte pin_column[COLUMN_NUM] = {16, 4, 0, 2};   // GPIO16, GPIO4, GPIO0, GPIO2 connect to the column pins
+
+Keypad keypad = Keypad( makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM );
+boolean blink = false;
+boolean ledPin_state;
+int boom = 0;
+byte ledPin = LED_BUILTIN;
+
+void keypadEvent(KeypadEvent key){
+    switch (keypad.getState()){
+    case PRESSED:
+        if (key == '#') {
+            digitalWrite(ledPin,!digitalRead(ledPin));
+            ledPin_state = digitalRead(ledPin); // Remember LED state, lit or unlit.
+        }
+        break;
+
+    case RELEASED:
+        if (key == '*') {
+            digitalWrite(ledPin,ledPin_state); // Restore LED state from before it started blinking.
+            blink = false;
+        }
+        break;
+
+    case HOLD:
+        if (key == '*') {
+            blink = true; // Blink the LED when holding the * key.
+        }
+        break;
+    }
+}
+
+void setup() {
+  Serial.begin(9600);
+  pinMode(LED_BUILTIN, OUTPUT);
+  digitalWrite(ledPin, HIGH);           // Turn the LED on.
+  ledPin_state = digitalRead(ledPin);   // Store initial LED state. HIGH when LED is on.
+  keypad.addEventListener(keypadEvent); // Add an event listener for this keypad
+}
+
+void loop() {
+
+  //Serial.print('Boom');
+  while(Serial.available() == 0){
+    Serial.println("Boom");
+    delay(1000);
+  }
+
+  if(Serial.available() > 0){
+    //Serial.print('No boom boom');
+    String msg = Serial.readString();
+    msg.trim();
+    if(msg == "Boom Boom"){
+      Serial.println("Recived something ...");
+      boom = 1;
+    }
+  }
+
+  if(boom == 1){
+    Serial.print("Waiting for new input:");
+    delay(5000);
+    
+    char key = keypad.getKey();
+    if(key) {
+      Serial.println(key);
+    }
+  }
+
+  delay(1000);
+
+}