I am having trouble figuring out what components that I can use to build a fuel level sensor, that will tell me when the fuel level is low and will activate the LED to turn on.
More information would be helpful. If it is for an auto with an existing electric (not electronic) gage/sensor then it might not be too difficult. Many of the gages like that are essentially voltmeters - you could look at the voltage going to the gage to give you the indication. A detailed shop manual would be a good resource.
hi there, I have this circuit but I cant remember yet where I have filed it, from what I can recall your signal source is from the gauge fed to the schmitt trigger device then to a couple of transistors to lite up us the LED & buzzer. A modification can be made so that the LED will blink and the buzzer will give a buzz-buzz-buzz.