Apache - Monitor serial port

[Daniel Pereira]

Hello people,
I'm a newbie in developer modules and I'm developing a module to monitor the
serial port.
So I'd like to make a module that should be performed any time. For example,
the apache should start that module each second for monitoring the serial
port.
How can the apache perform my module each second?
I'm not sure if that's the best option.
Thanks a lot,
Daniel Patrick