My sons want to accomplish similar science projects. (The practical use of the projects is to time-limit gaming during a 24 hour period.) For the younger son, we want to configure relay and off-the-shelf timers to limit play to 2 hours per 24 hour period. We prefer to use a momentary contact switch for the trigger, but are now using a 2 hour spring timer. We are having trouble with the 22 hour "lock out" period. Any help will be appreciated! My older son wants to build a circuit board that does the same thing. We have looked at a "repeating interval timer" design from the internet. It looks ok, but one of the resistors is labelled "4k7". Any idea what that is? Also any other drawings would be helpful. Thanks in advance.