jfoote / brainthrottle

Detects when you are skimming (instead of reading) and dims the screen to slow you down

brainthrottle

Attempts to detect when you are skimming text (through excessive scrolling) and progressively dims the screen to slow you down.

Crappy cell phone video demo

Sometimes we skim when we shouldn't. This is a simple, for-fun experiment in fixing that.

How to use

Compile

Install OSX developer tools, then:

$ clang -o brainthrottle brainthrottle.c -framework IOKit -framework ApplicationServices -Wl,-U,_CGDisplayModeGetPixelWidth -Wl,-U,_CGDisplayModeGetPixelHeight -mmacosx-version-min=10.6

Run

When you should be comprehending what you are reading and scrolling is a good proxy for skimming, run brainthrottle. Use Ctrl-C to exit.

$ ./brainthrottle

You can how much scrolling triggers a screen dim, how long the screen is dimmed, etc. via constants at the top of brainthrottle.c. Command line options are on the TODO list.

Design

main installs an EventTap. The EventTap callback (handleScroll) tracks the scroll displacement (recentScrollTotal). When scrolling exceeds scrollThreshold, each time the EventTap fires a timer is created (or restarted) and the screen dims. When the timer expires, the screen brightness is restored to its original value (prevBrightness).

Known issues

• OSX only
• Only works with the main display
• Main display brightness must be controllable via OSX
• Skim detection message should have a timestamp for logging and analysis
• Tuning parameters should be command line arguments
• Demo is crappy cellphone gif

Author

Jonathan Foote
[email protected]
28 June 2015

Thanks to Matt Danger for blogging about OSX brightness control back in in 2008: http://mattdanger.net/