You can use the OBD-2 / EOBD diagnostic connector required in all recent cars to read out a lot of interesting data if you have a suitable interface adapter and a notebook computer. An even more practical solution is to use the stand-alone analyser described here, which can be used as a hand-held unit or fitted in your car. Diagnostic data is evaluated using an ATmega16 and shown on an LCD with four rows of 20 characters. Up to eight parameters can be constantly shown on the display while you’re driving. Having this information at your fingertips can be especially handy if you have car trouble.