Gas sensors are important to monitor and warn of a dangerous gas level which can be harmful to organic life. Sophisticated gas sensor systems are being used in medical diagnostics, manufacturing processes, photo-voltaic systems, refineries, vehicles, homes and waste-water treatment systems.
Read on to view several reference designs on Gas sensors from the industry which offer their detailed design with all necessary documents:-
Micropower Toxic Gas Detector:
This reference design describes a low power, battery operated, portable gas detector using an electrochemical sensor. The design uses an Alphasense CO-AX Carbon Monoxide sensor. Because of the circuit’s extremely low power consumption, two AAA batteries or a 2.3 V to 5.5 V power supply can power the circuit. The circuit provides reverse voltage protection, and the ADP2503 high efficiency, buck-boost regulator regulates the input supply to the 5V required to power the sensor. To measure the gas concentration, a 16-Bit Sigma Delta ADC with On-Chip In-AmpAD7798 is utilized. A microcontroller with a high-resolution ADC can further reduce the circuit’s power consumption to increase the battery life up to one year. More on this Reference Design
Small & Reliable CO Detector using Electrochemical Sensor:
This reference design from Zilog describes a reliable electrochemical CO sensor based on a Zilog’s Z8 Encore XP microcontroller (MCU) and the Sixth Sense ECO-Sure (2e) CO sensor. Two important on-chip peripherals of the MCU that help to implement the solution include a Transimpedance Amplifier and a sigma-delta analog-to-digital converter (ADC). The transimpedance amplifier amplifies the current variations produced by the CO sensor and sends them to the on-chip ADC. The on-chip integrated hardware of the MCU minimizes the board space with very few external components. The MCU implements a power management routine to conserve power. The design discusses the complete hardware architecture and firmware implementation of the CO detector solution. More on this Reference Design
Smartphone-connected Multiple Gas Sensor:
TI offers a Gas Sensor reference design which can be used to monitor gases like carbon monoxide (CO), oxygen (O2), ammonia, fluorine, chlorine dioxide and others in many applications including mining, household CO sensing, healthcare and industrial controls. The design adds a Bluetooth Low Energy (BLE) feature to connect to an iPhone or an iPad via an iOS application running on them. A CR2032 coin-cell battery runs the system. An analog front end (AFE) from TI, LMP91000, interfaces directly with the electrochemical cell and a BLE system on a chip CC2541 with 8051 MCU core. The targeted gas sensor can be replaced based on the application, while keeping the same analog frontend (AFE) and BLE design. More on this Reference Design