diff --git a/src/MAX30105.h b/src/MAX30105.h
index 0dcace7..4002212 100644
--- a/src/MAX30105.h
+++ b/src/MAX30105.h
@@ -39,7 +39,9 @@
 #else
 
   //The catch-all default is 32
-  #define I2C_BUFFER_LENGTH 32
+  #ifndef I2C_BUFFER_LENGTH
+    #define I2C_BUFFER_LENGTH 32
+  #endif
 
 #endif