diff --git a/README.md b/README.md
new file mode 100644
index 0000000..8140457
--- /dev/null
+++ b/README.md
@@ -0,0 +1,6 @@
+# cosmicpi-arduino
+
+The firmware must be in a file called `cosmicpi-arduino.cc` with a symlink to `cosmicpi-arduino.ino` in the same directory in order to
+make the Arduino IDE happy.
+
+The Adafruit libraries here have been modified.