diff --git a/rotator/README.md b/rotator/README.md
index 847f966..e9a2176 100644
--- a/rotator/README.md
+++ b/rotator/README.md
@@ -2,6 +2,11 @@
 * two rotators
 * two displays
 
+## required libraries
+* https://github.com/adafruit/Adafruit_SSD1306/
+* https://github.com/adafruit/Adafruit-GFX-Library
+* https://github.com/adafruit/Adafruit_BusIO
+
 ## PINs
 * IDE = Physical = Usage
 * x = 1 = reset (connecto to master)