Hi ! I can do this with a small & chip uCPU (eg attiny25/45/85) I only need soem details about "pulsed" signal - period, duty cycle, any restriction in "detecting" etc. The relays can be conencted directly to the chip if the curent is not exceeding 10-15 mA or through 2 transistors. I can design the electrical schematics, PCB layout and make a prototype + SW of course. BR Horia Pop