I have an hour-meter on my oil-fired furnace that I put on when the unit was installed. I used to have time (and no software) to record the daily numbers and get an idea of how much oil I burned based on the temperature at my house. Degree Days and Heating Days are available, but not for my location exactly.
Now with things like WeeWx and Weather Display having all sorts of other sensors one can interface, I wondered about having some sort of on/off sensor interface through some hardware to make available to the software an indication of whether or not the furnace was firing. Don't know why, but I guess I'm interested to see when it is on and compare to overnight temperature drops, especially when it gets sub zero and a big wind chill pulling heat away, like blowing on hot soup to cool it.
Anyway, any thoughts on what would be a SAFE way to interface? I can see if I can get a closure signal (low voltage, isolated) rather than try to make some sort of connection to the 120v that feeds to the meter or burner, since I don't need to end my career with an unexpected zap, or ruin all the stuff I've wired up so far.
One choice that seems likely to be of use would be a Campbell Scientific CR3000 that runs a lot of sensors that don't belong to any one commercial station like a Davis, Rainwise, etc. I can test a port similar to seeing if a rain gauge has made connection or a high/low value on a voltage port, then log a value from that to a table value, and do what it takes to integrate the on-time.
The next step would be to send that to Weather Display or something as a value that can be graphed, like a solar reading, a temperature or whatever.
Has anyone suggestions as to a safe interface from either the thermostat or the 120v to isolate to say a 5 volt signal that would be safe?
Any ideas on how to best present time-on values to display software such as WeeWx or Weather Display?
Thanks. Dale
