Hy guys tell me is possible to made arduino lightbulb monitoring system in car? I know that the vag group uses ohm meter for lightbulb resistance and when lightbulb is broken then indicate that one bulb don't work.... I readed that the max input voltage of anolog pin is 5v so i cant read resistance of lughtbulb what about current meter?
Look for a Hall effect current sensor. They are isolated so the 5V Arduino is safe.
A simple method I used in the old days was to wrap a few turns of wire ( around 6?) around a reed switch . This looped wire is connected in series with the bulb . Adjust the turns so the relay pulls in when the bulb works . The reed switch is a nice digital input .
Or, a photo-transistor, photo-diode, or LDR.
Or, some fiber optics up to the dash with no electronics!
(You'd have to cut the wire to insert a Hall effect sensor, and you'd probably have to cut-and-splice to make a coil for a magnetic reed switch.)
hammy:
A simple method I used in the old days was to wrap a few turns of wire ( around 6?) around a reed switch . This looped wire is connected in series with the bulb . Adjust the turns so the relay pulls in when the bulb works . The reed switch is a nice digital input .
Good one...used to use the same arrangement to monitor glow plug operation in model aircraft at 1.0v.