Read keypress on unfocused window

[dalibor]

Hello all who read this post.
I'm a electronic enthusiast, and new in Pascal world.
I made an arduino project, to light the lamp over Wifi.
Now i want to make pascal app that run in backgraound,hiden through which I will turn on and off that lamp, by sending UDP massage.
I found everything except how to read key press when program window is unfocused/minimized/hiden.
So how to make program read keypress, when windows is unfocused?

System Win 8.1
Lazarus 1.8.4

[HeavyUser]

http://www.swissdelphicenter.com/en/showcode.php?id=147

[dalibor]

Thank you for this quick answer.
This is just what i need.
Looks like I did not use the right words when I searched thru web.