clean up before sharing

[hw/greenhouse] / README

diff --git a/README b/README
index 06a2292b2f2e493f78352eea9ebddebb8c853a7e..164d25ad7a01323a4e7836295e4064686b532277 100644 (file)
--- a/README
+++ b/README
@@ -33,3 +33,10 @@ References:
 
     pcb layout in gEDA of an Arduino shield:
        http://lowvoltagelabs.com/products/videooverlayshield/
+
+    5 to 3.3 volt level shifting with a MOSFET ...
+       http://www.rocketnumbernine.com/2009/04/10/5v-33v-bidirectional-level-converter/
+
+    DS1307 i2c example code
+       http://www.glacialwanderer.com/hobbyrobotics/?p=12
+