I've a work in progress. Relays are easy to control but the problem is the amount they switch on and off. Depending on the settings, insulation of the box, air flow and heat source, this can happen several times a minute. Even if it was every minute for 21 days thats 30,2400 times its switches on and off. They contacts will wear out.
There is a PID library for arduino that you use with Mosfets. Thats what I am using now to avoid that problem.
Last edited by jigsawnz
on Sat Nov 17, 2012 11:07 pm, edited 1 time in total.
A person only needs two things in life. Some CRC/WD40 to make things go and some duct tape to make things stop.