An improved, selective, radiation sensing device is provided which includes a thin strip of pyroelectric material. One side of the material is coated with a continuous layer of metallic material to form an electrode while the opposite side is coated with at least a pair of electrodes and the output of the electrodes are electrically connected to a differential amplifier. A layer of energy filter material is applied over the continuous electrode. This layer is transparent to all energy outside of a desired energy frequency band to which the device is to be sensitive but absorbs and converts to heat all energy applied which is within this band. This heat is conducted quickly into the pyroelectric material which produces a voltage change in the output from the corresponding electrodes. By positioning the device at the focal point of a concave mirror, the output from the electrodes can be used to energize an alarm signal or the magnitude and frequency of the output of the device can indicate the size and movement of an energy source such as a human body. A novel method of making the device is included which facilitates the fabrication and reduces handling problems and costs.