Innovation: Sensor Gas methane, CO, CO2, Ethanol, LPG

Description

Gas sensors generally detect the chemical changes that occur in the room sensor, so that such sensors are usually placed in a closed room.

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Here's an excerpt from the theory of gas sensors (sources by: http://www.scribd.com/doc/18271343/Skripsi-Lengkap-Sensor-Gas-LPG)

Formed on the outer surface of the crystal. Formed surface tension will
inhibit the rate of electron flow as shown in illustration Fig:

Illustration picture O2 uptake

In the sensor, electric current flows through the connection area (grain boundary) of SnO2 crystal. At the junction, the absorption of oxygen prevents the charge to move freely. If the gas concentration decreases, deoxidation process will occur, the meeting surface of the negative charge of oxygen will be reduced, and the resulting decrease in barrier height of the connection, ie there is a presence of CO gas is detected then the chemical equation can be described as shown in the following equation.

CO + OAD (SnO2X) → CO2 + (SnO2X) * ... ... ... ... ... ... ... (2

By decreasing the barrier then the sensor resistance will also decrease thus the value of any given sensor will decrease.

Application

Gas sensors are usually coupled with some other components such as actuators alarm, monitoring, relays, and various other controllers. Here are some sample schematics of gas sensors that can be made easily:

The following schematics are used to create a functioning gas sensor to detect CO, CO2, Methane, Ethanol. This gas sensor using the sensor type TGS 202 and a buzer as actuator.

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