Abstract: The industry practice to detect and identify objects such as wires, cables, pipes and tuned coils is to inject a known tone from a tone generator into the object by conduction or induction, occasionally with tagging information. The invention is a tone detection apparatus, also known as the tone probe, to detect the presence of such injected tones that makes use of a microphone or audio electrical input of a mobile computer and software application running on the mobile computer such as a contemporary “smart-phone”. The use of a mobile computer reduces the cost of this tone probe and provides the ability to use mobile internet connection to communicate and store the tagging and location information about object under detection. The display of the mobile computer allows providing more information than a typical tone probe.