diff --git a/README.md b/README.md
index 1f677fa..6ab83f5 100644
--- a/README.md
+++ b/README.md
@@ -91,6 +91,7 @@ RadiationD-v1.1(CAJOE):
   measures up to ~30V
 
 ## ToDo
+* https://tinker.yeoman.com.au/2016/05/29/running-nodemcu-on-a-battery-esp8266-low-power-consumption-revisited/
 * https://hackaday.com/2014/10/25/use-a-cheap-pin-diode-as-a-geiger-counter/ (opengeiger.de/elektronik.html)
 * Solar power