Detecting Circuit PUBLIC

Not provided.

Need help to create a signal detecting circuit. Signal to detect is in a black box environment, can only measure voltage over resistor, not same ground as measurement circuit.

Detect Signal Ur1= 5V 1ms pulse but dont trigger on diagnostic Ur1=100mv 1ms pulse. Need to measure over 2.2ohm the existing resistor without disturbing measured circuit to much. When detecting signal, turn on diode and keep it on until retested by button.

1. Create functioning circuit
2. Use as small and few parts as possible

Created some small stuff to get started, signal generation and a possible part of the monitoring system. Only the R1 can be used as known, the rest on the left in unknown. voltage over R1 is known but not system voltage or grounds.