LED for simulating injection pulse

one of the aggreed outcomes of this project is that we should include the fuel system. however when the atomized fuel meet with sparks from the spark plugs, dangerous can happen. under safety concideration, our superviser have agreed to cancle out the application of fuel pump. without the fuel pump runs fuel into the injectors, we have to use LED to simulate injection pulses.

If an LED were connected directly across a 12 volt battery, it would light brightly, but only for a few seconds. Excessive current can destroy the P-N junction. The average LED requires only about 20-30 mA. So a resistor must be connected in series with every LED to control current flow. The method we have used to protect the LED is to connect a 470 ohm resistor in series with each LED. The resistor can be connected to either the anode or the cathode end.