Friday, April 3, 2015

Lantern Brightness Sensor

This is a quick update (easter easts a good fraction of my time) on the Lantern project.

First of all, I've created a Trello board for tracking and planning Lantern development. I will update it with separate tasks for software hardware and testing efforts.

I've been busy hacking on some new low-cost open source hardware that could be used for testing and debugging brightness controls in an automated way. Check out the board for details. If you are an experienced hardware designer and would like to help me out (either to mentor me or JFDIing it then by all means, I will welcome all help :-).

I'm a novice at hardware but I'm slowly getting through the basics of taking measurements with the TSL2561 sensor. Once the prototype is working well enough I plan on writing a few tests that can:
  • check that software control does result in a change of panel back-light brightness
  • measure the effective LUX value seen for each available software setting
  • automatically determine if brightness zero turns the back-light off 
  • maybe measure response time (difficult to do right)
This covers one half of the back-light story - software control. There are also hardware buttons that may or may not do something via ACPI (depending on the age of the device), that may or may not be a normal key or may crash and burn your machine (well, just kidding). For now I want to focus on the ACPI side and just write a simple test that looks for the anticipated ACPI events that should be sent when those keys are pressed. I plan on running that on all of the hardware Canonical has access to to get a quick estimate of how useful that is.

Oh, and I got http://pid.codes/1209/2000/ (see here for the backstory)