Need Help...ideas for two projects!

Project 1:
I often let my dog outside through my porch door, leaving the door open a smig so that he can come in on his own. The trouble is that I don't know when he comes back in and in the North East this time of year it let an awfull lot of heat out!

I am looking for a way to detect that he has come in and then signal me inside so I can let him in the main house and shut the door behind him...
nope! I have'nt yet tought him to close the door behind him.


Project 2:
I'd like to setup two fans in my basement windows, one blowing out, the other blowing in. I want them to turn on when the humidity outside is less than the humidity inside, and turn off when the humidity outside is greater to or equil to the humidity inside.
Any suggestions??


Thanks

kayaker said:

Project 2:
I'd like to setup two fans in my basement windows, one blowing out, the other blowing in. I want them to turn on when the humidity outside is less than the humidity inside, and turn off when the humidity outside is greater to or equil to the humidity inside.
Any suggestions??

Thanks

Click to expand...

that could be done using two humidity sensors like
**broken link removed**
and a comparing logic ckt will do the rest