diff --git a/CMakeLists.txt b/CMakeLists.txt
index 46d701b..069327d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -25,10 +25,9 @@ pico_sdk_init()
 
 # Add executable. Default name is the project name, version 0.1
 
-add_executable(pico_keyer
-  pico_keyer.cpp
-  settings.cpp
-)
+add_executable(pico_keyer)
+
+add_subdirectory(src)
 
 pico_set_program_name(pico_keyer "pico_keyer")
 pico_set_program_version(pico_keyer "0.1")
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
new file mode 100644
index 0000000..e58fc71
--- /dev/null
+++ b/src/CMakeLists.txt
@@ -0,0 +1,4 @@
+target_sources(pico_keyer PRIVATE
+    pico_keyer.cpp
+    settings.cpp
+)
\ No newline at end of file
diff --git a/pico_keyer.cpp b/src/pico_keyer.cpp
similarity index 100%
rename from pico_keyer.cpp
rename to src/pico_keyer.cpp
diff --git a/settings.cpp b/src/settings.cpp
similarity index 100%
rename from settings.cpp
rename to src/settings.cpp
diff --git a/settings.h b/src/settings.h
similarity index 100%
rename from settings.h
rename to src/settings.h