I want to make my own plug-in countdown timer switch using arduino because commercially available ones are not quite what I want. They are either too difficult to set time, have a limited time range, cannot set arbitrary time increment, or don't show remaining time.
The hardware components needed are
- high current relay (20A 120V)
- project box
- power supply for arduino
Is there a kit that has these components nicely layout so I can focus on the programming?