Today I will show, how you could add an arbitrary script or application to the P-Button of your Acer 1825.
A little script, which checks if the onscreen keyboard onboard is running.
If onboard is running it will be closed if not it will be started.
[you need to install onboard: sudo apt-get install onboard]
running=$(pgrep onboard | wc -l)
if [ $running -gt 0 ] ;then
Save this script under e.g. onscreenkeyboard.run and give permission for execution chmod +x onscreenkeyboard.run
Now add following line to your /etc/rc.local
setkeycodes e070 112
if you want test it temporary in terminal: sudo setkeycodes e070 112
After reboot or the above command start: