Tired of straining your eyes, trying to see your non-illuminated keyboard at night While most of the people who read this can type blind, for some special characters the lack of light can get irritating. Hack your keyboard so that when you tap CapsLock twice, a bright white LED comes on, illuminating your entire keyboard for late night movies and LAN parties. No one actually uses the CapsLock key, so it’s perfect to sacrifice for this project.
Now we have connections to the LED, the capslock-indicator and to 5V, we need some logic to make sure the LED toggles when the capslock LED goes on and off again in a short timespan. While I could have used regular logic, the problem can also be solved by throwing an uC to it, which has the added advantage that it can be an one-chip solution. I used a cheap microcontroller with a small piece of
firmware to do the job.