Provided are, among other things, devices for and methods for performing thermal signature assays on a two or more samples in an array, using active/control base thermopiles, the method comprising: [a] performing a heat transfer to the two or more samples in each of a two or more containers, using at least one base thermopile in thermal communication with the two or more containers; and [b] determining a total heat transferred to the samples by the base thermopile in step [a]; and [c] sensing in real time a temperature difference between a first sample and a second sample of the two or more samples resulting from performing step [a].