Add section on input devices.

Change-Id: Ib9c4909881df505b11537c28bd08182933a5565a
diff --git a/src/tech/index.md b/src/tech/index.md
index f7aa958..5653bda 100644
--- a/src/tech/index.md
+++ b/src/tech/index.md
@@ -52,3 +52,9 @@
 core Android platform.
 
 [» Android Security Overview](/tech/security/index.html)
+
+## Input Technical Information ##
+Android's input subsystem is responsible for supporting touch screens,
+keyboard, joysticks, mice and other devices.
+
+[» Input Information](/tech/input/index.html)