I wrote a very simple program to act as an thermostat.
I used this command:
Duemilanove is the board I am using.
I hooked up some wires from digital pin 3 to a reed relay.
Also a ground to complete the circuit.
Problem is when I run the program nothing happen, no relay click and no test across, doesn't seem to have anything going out of the pin when that is turned high, not sure where to go now, please help.
Could be several things. Do you have a pinMode(3, OUTPUT); command in your sketch to set the pin to output mode before you do the digitalWrite? Do you have a link to the specific relay you are using to see if a digital pin can drive it properly or not? Is it a 5vdc rated coil? some reed relays will work directly, some will not, depending on their coil current requirement. Also posting your sketch always helps when asking for help as otherwise we have to make assumptions on what you may or may not have done correctly or incorrectly. We are blind, help us help you. ;)