diff --git a/arduino/README.md b/arduino/README.md
index cb3e4b9e..61e64d99 100644
--- a/arduino/README.md
+++ b/arduino/README.md
@@ -1,4 +1,4 @@
-This code is for the STM32 or Pro Micro acting a payload to the CubeSatSim.
+This code is for the STM32 or Pro Micro acting as a payload to the CubeSatSim.
 
 Code that runs on both boards is in this directory.  Code that only runs on a particular board is in the directory for that board.