Conventionally, a security guard is employed at a swimming facility to monitor if there is any sign of intruder that enters the swimming facility during closing hours. However, not all the swimming facilities can afford to employ the security guard, and this leaves the swimming facilities unattended during closing hours. Sometimes, the security guard's negligence allows the intruder to enter the swimming pool at closing hours without permission. Due to the lack of security at swimming facilities, there is a rise in drowning cases in recent years. Therefore, there unattended swimming facilities require either an adequately safe enclosure of fence, or an intruder alarm for safety measures. There are a few patented technologies over the prior art relating to the monitoring device. One disadvantage is that the device is unable to locate the position of a drowning person in the swimming facilities, and therefore preventing the security guard to rescue the drowning person on time.