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Dan Nixon

Code Monkey, Electronics Engineer, Mad Scientist.

Auto monitor brightness controller

By Dan Nixon on 2014-06-24

Lately I’ve been having issues with the automatic ambient light compensation in my LG monitor being heavily skewed by the fact it only samples light from in front of the panel, which for a lot of the time is not a huge issue, however I have started using my monitor in front of a south facing window so have a constantly changing source of light which is undetectable by the monitors sensor but does heavily influence the desired backlight intensity.

Since the monitor does have an RS232 port with a pretty good set of scope from controlling the monitor (including the backlight intensity) I decided to just make my own controller, especially since there are times I want to manually adjust the backlight and getting at this setting through the menu can be very time consuming (especially when not using the remote).

How I ended up making this was by having the front enclosure (pictured below) contain just the front panel electronics and mount and Arduino UNO on an Acrylic VESA panel on the back of the monitor, originally I had planned to make a custom board and have everything in the front enclosure but only had an RS232 shield to hand. The Arduino is powered form the monitors USB port.

As it is I haven’t get a lot done with the auto mode yet, I am trying a few different ways of averaging samples and generating a backlight intensity value.

Controller Enclosure

Controller Enclosure

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