diff --git a/requirements.txt b/requirements.txt
index f0b7f74729a..1d6089715f9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -76,3 +76,4 @@ python-forecastio>=1.3.3
 
 # Firmata Bindings (*.arduino)
 PyMata>=2.07
+pyserial>=2.7