To give more accurate altitude reading you have to be able to set the sea level pressure for your area. The attached patch to weather_board.ino
displays this value and allows you to adjust it with the 3 buttons. Button 0 increases it, Button 2 decreases it and the value of the change is set to
0.01 hPa if button 1 is released and 1.0 hPa if button 1 is pressed. By setting the pressure a sea level you get a much more accurate reading for
Patch is for weatherboard 2 only.