A contactless power transmitting device is provided with: a primary coil that can be magnetically coupled with a secondary coil of a contactless power receiving device; a first temperature sensor that detects the ambient temperature of the primary coil; a second temperature sensor that detects the temperature at a different location to the first temperature sensor; and a control unit. In one embodiment, a positioning signal is received. In most aspects of the invention, the first and second oligonucleotide probes preferentially hybridize to the bridging oligonucleotide in the absence of a target nucleic acid.