In an embodiment, a connection is established between first and second Internet of Things (IoT) devices. After a determination is made to execute a proximity detection procedure, the second IoT device outputs an audio emission and a data packet at substantially the same time. The first IoT device detects the audio emission via a microphone and receives the data packet. The first IoT device uses correlation information to correlate the detected audio emission with the data packet, whereby the correlation information is contained in the detected audio emission, the data packet or both. The first IoT device uses the correlation between the detected audio emission and the data packet to calculate a distance estimate between the first and second IoT devices.