From 144b2ed5888c16fe29241882787a12415e3ad955 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tobias=20Sch=C3=BCrg?= <tobiasschuerg@gmail.com>
Date: Sun, 22 Apr 2018 12:11:58 +0200
Subject: [PATCH] Added formula to readme.

---
 README.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/README.md b/README.md
index 0639f5e..e4a472a 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,10 @@ https://revspace.nl/MHZ19
 
 ## Implementation
 
+```
+C ppm = 5000 * (T_high - 2 ms) / (T_high + T_low - 4ms)
+```
+
 The implementation is mostly based on  https://forum.arduino.cc/index.php?topic=525459.msg3587557#msg3587557