diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index e58fc71..510430c 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,4 +1,5 @@
 target_sources(pico_keyer PRIVATE
     pico_keyer.cpp
     settings.cpp
+    keyer.cpp
 )
\ No newline at end of file
diff --git a/src/keyer.cpp b/src/keyer.cpp
new file mode 100644
index 0000000..83f631d
--- /dev/null
+++ b/src/keyer.cpp
@@ -0,0 +1,14 @@
+#include "keyer.h"
+
+void Keyer::run()
+{
+    switch (state)
+    {
+    case State::WAIT:
+        // do nothing
+        break;
+
+    default:
+        break;
+    }
+}
\ No newline at end of file
diff --git a/src/keyer.h b/src/keyer.h
new file mode 100644
index 0000000..96abae0
--- /dev/null
+++ b/src/keyer.h
@@ -0,0 +1,18 @@
+#ifndef KEYER_H
+#define KEYER_H
+
+class Keyer final
+{
+public:
+    enum class State
+    {
+        WAIT
+    };
+
+    void run();
+
+private:
+    State state{State::WAIT};
+};
+
+#endif
\ No newline at end of file
diff --git a/src/settings.cpp b/src/settings.cpp
index 637e94e..2f5c147 100644
--- a/src/settings.cpp
+++ b/src/settings.cpp
@@ -1,6 +1,6 @@
 #include <cstring>
 
-#include <pico/stdlib.h>
+#include "pico/stdlib.h"
 
 #include "settings.h"
 
diff --git a/src/settings.h b/src/settings.h
index 3e8ddcf..2b36485 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -1,7 +1,7 @@
 #ifndef SETTINGS_H
 #define SETTINGS_H
 
-#include <pico/flash.h>
+#include "pico/flash.h"
 
 const uint16_t MAGIC_NUMBER = 2;