Rain detector

I have a rain sensor hl-83 and a control board hl-01.
I know I need a +5 vdc power supply.
I nee help interfacing the DO TTL of the control board to a device with a relay output to sound a small bell.

Thank, John

I'm curious to hear more about your rain sensor. Is it accurate for misty rain? Do you need drizzle? Does it work well?


Interesting article here....