As used in this part, "transdermal monitoring device" means any device or instrument that is attached to the person, designed to automatically test the alcohol or drug content in a person by contact with the person's skin at least once per one-half (1/2) hour regardless of the person's location, and which detects the presence of alcohol or drugs and tampering, obstructing, or removing the device.
T.C.A. § 55-10-424