Circuit Lake

Gas sensors are employed in a wide range of applications in the fields of safety, health, instrumentation etc. Common examples are domestic/commercial alarms for explosive or toxic gases, or in automotive application as gas leakage detectors for LPG powered cars and exhausts detectors inside any fuel-powered truck/car. Such sensors, nowadays, are found also in applications involving air quality control systems and pollution monitoring. The project aim is to show how to build gas detector based on small microcontroller, AVR ATtiny45. The MCU can be employed to replace a lot of external components while adding extra functionalities at a cost comparable as a simple integrated comparator.

“The final circuit results very compact in dimensions, cost effective but at the same time very flexible in applications and functionalities. the use of an AVR microcontroller makes easy the possibility of the project to be modified and adapted to several sensor types and application areas,” said Fabrizio D’Angelo, the designer.

In Tiny Gas Detector project, the hardware and microprocessor firmware have been optimized to implement a smart LPG gas alarm (LPG stands for Liquefied Petroleum Gas) for domestic or automotive use. Here are main features of the project : full sensor parameters control for maximum reliability; temperature compensation for better measurement accuracy; six steps of gas alarm levels with Led and acoustical indicators; store of “maintenance’ parameters in a non-volatile memory (tiny45 internal eeprom); and logging of any alarm and failure events (all stored data can be transferred via RS232 serial interface).

Gas Sensor Alarm
Project Firmware, Schematic and Documentation
circuitcellar.com