Hi guys,
I will try and summarize my thoughts on most of your points raised. Using a laptop ofcourse takes away the fun of building something but it has its issues. Firstly the laptop power system obviously runs on different voltage so an invertor would be needed to connect its power adapter to it. The power consumption is higher on a laptop/macmini as compared to the low voltage motherboard i am using, this would impact the drain on the battery when you are switched off. Ideally you want to leave your car system in a standby mode so it can be in a usable mode quickly as you start driving, not wait for the system to boot up everytime.The laptop has its limits on upgradability and installation of a laptop in an automotive environment is not that easy. However some people have cannibalised their existing older laptops for such a system. The input methods are most key, the keyboard and mouse is really not practical for a car computer in its primary function. For instance if i need to change a song or start navigating to a point of interest or something like that. I would need to park on the side of the road in the interst of safety if i intend to do it through a keyboard/mouse. I am using a touch screen as my main input device and also a software front end specific for car use. If it was just for the sake of putting a computer in the car certainly a mac or a latop would have made a substitute but my intention was to make a car pc that feels like is a car pc and not a pc put in a car (if you know what i mean). The car functions like the ECU and reverse camera/sensors etc are all going to be integrated into this and i would strive to make it seem like a factory option.
If you are just looking at the cost of the whole system against the cost of the laptop or mac mini then its really not a fair comparison. I would need to buy most of the addons for the other as well and you need to add those to the cost of the laptop too, like the OBD scanner, the touch screen, the gps receiver, the FM radio, the reverse camera etc.
About putting a tablet PC or laptop on a mount near your dash, come one guys would anyone want to leave it visible like that ? If not would you keep removing it and putting it back everytime you want it ?
cheers.