I Think whit a good acurate gauge is enought for this aplication, its true that good ones are expensive , but Also the time to build one is not for free, I dont like specially Arduino for this aplication , but any way this is another question , bluesea is nice Dash, I Will use this
The temperature monitor works great. This was after our first hour of driving Portal temps seemed very stable.
It seems that even the direction of the wind affects the portal temperature. We had been driving at 95 Kph for about 40 mins with a strong cross wind. I could not figure out why one. portal was running hotter than the other side. I stopped and even checked the oil levels. The road then turned 90 Degrees and the temp started to drop.
This was the result 10 minutes later. Later on the road changed direction again an the temperatures evened out again. Seems like the porta temperatures change regularly.
Looks good, - this is what I came up with, 1 temperatur, 1 humidity, 1 water temperature (with a alarm and a red LED), 1 car battery and 1 house battery voltage... on a B/W 1.3" inch OLED... I also managed to program the Arduino to draw the symbols... You can do whatever you want on the 128 by 64 dot display