diff --git a/viz/README.md b/viz/README.md
index b5299b2..badeccb 100644
--- a/viz/README.md
+++ b/viz/README.md
@@ -1,3 +1,19 @@
+Python script to visualize data, e.g. roll and pitch, used for testing and [demonstration purposed]()
+
+Accepted file format from data recording, e.g.
+```
+1,2
+2,3
+3,6
+4,9
+5,4
+6,7
+7,7
+8,4
+9,3
+10,7
+```
+
 For requirements, see [requirements.txt](requirements.txt)
 
 On linux, you need to install `tkinter` with