Web alarm clock for 12:01 a.m.
While preparing early to relieve the guard at your residential village gate, set the alarm for 12:01 am before gathering your logbook, keys, rain gear, and ID. This gives you a clear cue to finish getting ready and leave with enough allowance for the trip to the gate before 1:00 am, rather than watching the clock between small tasks.
Your gate duty may begin amid electric fans, passing tricycles, barking dogs, or voices from a nearby television, so choose a volume you can hear above the expected background noise. Test the signal from the same place where you will wait, then keep the phone close instead of leaving it across the room. The alarm cannot alert you if its page is closed or the phone goes to sleep, which could make you late for the guard change; keep both active until it sounds.
Because people in the house may already be asleep at 12:01 am, prepare your bag, shoes, keys, and raincoat earlier and avoid searching through drawers after the signal. Use a distinct but moderate tone, place the phone near you, and silence it as soon as you are awake. A short vibration can help if the phone rests on a stable surface that will not amplify the sound through a shared wall or floor.