Abstract: A distance sensing system includes a first electronic device and a second electronic device. A second processing unit of the second electronic device sends a wireless signal via a second short-range wireless communication unit. When a first processing unit of the first electronic device receives, via a first short-range wireless communication unit, the wireless signal from the second electronic device, the processing unit generates an estimated distance value indicating an estimated distance between the first electronic device and the second electronic device based on signal strength of the wireless signal. When the first processing unit of the first electronic device determines that the estimated distance value is less than a predetermined distance, the first processing unit outputs a notification via the first output unit, so as to send the notification to a user of the first electronic device when the second electronic device is close to the first electronic device.