Im using a PIR sensor with a kind a delay for the bluelight(solenoid) to remain on. To know status of active there is a blink of onboard led at the interval set. You walk in from of the sensor light remains on for x amount of minutes. As each event occurs it hits a counter which will then be translated by x number of events lights up a led. There is serial feedback to understand the state of the cpu or operation. The end project will be more complicated and im trying to get all these elements under one arduino. This is the first time i use millis, call functions, or while conditions so im slowly progressing.