diff --git a/OpenGlass/firmware/firmware.ino b/OpenGlass/firmware/firmware.ino
index ca000b025..44be52819 100644
--- a/OpenGlass/firmware/firmware.ino
+++ b/OpenGlass/firmware/firmware.ino
@@ -35,6 +35,7 @@ OpusEncoder *opus_encoder = nullptr;
 #define CHANNELS 1
 #define MAX_PACKET_SIZE 1000
 
+#define FRAME_SIZE 160
 #define SAMPLE_RATE 16000
 #define SAMPLE_BITS 16