Electronic reading of a mechanical gas meter based on dual magnetic sensing

Abstract

This article proposes a measurement system controlled by a microcontroller unit (MCU) for the electronic reading of a mechanical gas meter. The measurement relies on dual magnetic sensing: (a) low-cost low-power primary sensing based on reed switches connected to the digital inputs of the MCU and (b) secondary sensing based on Hall-effect sensors connected to the analogue inputs of the MCU. In addition, both sensing strategies have an active and a passive element to achieve an output that is insensitive to external interfering magnets. A prototype has been implemented and characterized under different test conditions to confirm its reliability.