I found this schematic for building an LED tachometer which uses an ignition coil signal. The LEDs light up sequentially as the Engine Revs increase, etc. I wanted to add an additional feature, and was wondering if anybody could help me figure out how to do it. Basically, what I am trying to do is have all of the LEDs start flashing/blinking every 20 milliseconds or so when the engine is over a certain RPM. Can this be done without too much complexity? Thanks for your help!