An electrochemical sensor device that is efficiently and economically produced at the chip level for a variety of applications is disclosed. In some aspects, the device is made on or using a wafer technology whereby a sensor chamber is created by said wafer and a gas port allows for a working electrode of the sensor to detect certain gases. Large scale production is possible using wafer technology where individual sensors are produced from one or more common wafers. Integrated circuits are made in or on the wafers in an integrated way so that the wafers provide the substrate for the integrated circuitry and interconnects as well as providing the definition of the chambers in which the gas sensors are disposed.