Connecting relay to 220v
osa-ss-212dm3 relay has 12V coil. You need osa-ss-205dm5 if you want to trigger by 5V and want to switch 240V AC.



UPDATE:
Note: you cannot feed that relay from MCU pin directly. Coil needs 540mW (it is ~110mA at 5V), so MCU will not be able to deliver such current (depends on MCU). You will have to use some switching transistor too.