Schloemilch 19 and others, and are known as electrolytic detectors.
Examples include americium 241 used in smoke detectors and Polonium 210 used in dust detection and anti-static devices.
Carbon monoxide detectors detect carbon monoxide detectors detect carbon monoxide, a poisonous gas with no smell, taste or color.
The camera has eight 4096 x 2048 pixel CCD detectors and performs imaging over a 52 arcmin wide field.
Other Methods These, such as soil conductivity meters, metal detectors and micro gravity, exist but will not be discussed here.