I’m afraid a digital fuel meter is still on the developing way. You can be the one to invent it in the near future.

PS: It is known that the fuel meter indicates the fuel storage in the vehicle fuel box showing with pointers or digital numbers; Besides, the fuel meter is made up of fuel surface indicator with voltage regulator and fuel head sensor;

BTW, the function of the low fuel level alarm device is that to get the attention of the driver with lighting alarm so long as the fuel is less than certain rated value.