Development of integrated microsystem for hydrogen gas detection

Abstract

A low-power microelectromechanical system-based metal-oxide gas sensor along with integrated signal conditioning unit is presented in this study to detect and quantify the variation of H 2 gas concentrations. The interface circuit controls the sensor operating temperature, measures the H 2 gas concentration, contributes a user-friendly interface and can be used with any suitable sensor network. A PIC16F877A microcontroller has been used for this purpose. The temperature of the sensors was stabilised by controlling the actuating voltage of the microheater. Temperatures of the microheater depend on the output voltage of the digital-to-analogue converter (DAC) and were measured by sampling the heater resistance through the use of a voltage divider and analogue-to-digital converters (ADCs). A microcontroller accordingly adjusts the output of DAC's in order to apply the appropriate steering voltage to the heaters. The method employed to measure the concentration of gases is to sample the voltage drop over the resistances of the sensors by ADCs. Alarming system for safety measure was also implemented in this design. The preventive action was taken by introducing an additional feature of wireless communication by sending short message service via global system for mobile modem to the designated emergency number.

A Review on the Development of Iot Enabled Hydrogen Sensing Systems

“…There exists a wide variety of non-traditional A/D conversion methods which are highly compatible with Smart Sensing Systems and are extremely cost efficient. The most significant of these include voltage to frequency methods, sigma-delta methods, single, dual and multi slope methods, pulse-width modulation methods, potentiometric methods, frequency to digital (F/D) conversion and RC charge time constant methods (21). All of these methods are capable of facilitating low power operation, multiple variable measurements, highly accurate readings with measurements error's compensation and can effortless implement the trade-offs pertaining to Analog to Digital or Digital to Analog conversion parameters with respect to rate of conversion and accuracy (29).…”

“…The PIC16F87 Microcontroller comes with a broad range of features such as 8kb of internal flash Program Memory, a large RAM area and is combined with an internal EEPROM (21). It is well suited for monitoring applications and real-time sensing systems as it possesses an 8-channel 10-bit A/D convertor, a RS232 connection for data transfer and a reset switch for program execution.…”

Performance analysis, modeling, and development of a signal conditioning unit of n-type metal oxide gas sensor for acetone gas detection

“…The output of the bridge is connected to a low signal amplifier. This work uses an AD623 instrumentation amplifier as a low signal amplifier [35]. To ensures the single and dual supply operations it is a modified version of the classic 3 opamp instrumentation amplifier.…”

Design of Combustible Gas Automatic Detection and Alarm System

“…If the alarming rate of these household gas and gas bases and transfer stations is calculated at 10%, the demand for combustible gas detection alarms is more than 20 million. This number will continue to grow as the whole society attaches greater importance to fire and explosion prevention and personal safety [6]. It can be seen that this alarm system has a broad market.…”