keyboard light readme

keyboard-lamp/README.md

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+Keyboard Lamp
+=============
+
+This is a keyboard lamp with adjustable brightness, that remembers last brightnbess level even when powered off.
+
+I've made it as a replacement for my broken ThinkLight.
+
+It uses ATtiny13, and the schematic is something like this:
+
+                               Vcc
+                                |
+                  +-------------+
+                  |             |
+                  |  +---u---+  |
+                  +--|       |--+    Buttons
+                     |       |
+     +--[180R]-|<|---|       |--BRT----o/ o---+
+     |        LED2   |       |                |
+     |             --|  t13  |--DIM----o/ o---+--- GND
+    GND              |       | 
+                  +--|       |----+
+                  |  +-------+    |            LED1
+                  |               |          +-|<|--[47R]-- Vcc
+                 GND              |          |
+                                   +-[10k]-|<  Transistor NPN
+                                             |
+                                            GND
+
+LED1 is the bright white LED, LED2 is an indicator that the brightness has been saved. You can leave LED2 out if you want.
+
+**Fuses** and other settings can be found in the Makefile.