so the idea is based on three components - a car Engine Control Unit (pre'96, no OBD2), a voltmeter with USB interface (like this, this or this ) and Nokia N810. The problem is that there are no drivers or software for linux to control these voltmeters, only windows. The Idea? Seeing all car related info (sensors, pressure, level, temperature, speeds, etc) on screen with user defined view and with user defined warnings. the ECU (I have toyota celica turbo 1990) sends sensor info on seperate wires in range of 0-5 Volts, the voltmeter reads as fast as 1ms. the other option is to have a Windows based PC somewhere hidden in the car and connect from N810 to it with wireless or smth. but you need to load windows everytime you start your car. How har is it to develop drivers and some software API for such voltmeters?