Semiconductor VS MEMS VS Fuel cell Breathalyzer: Pros & Cons
What is a breathalyzer for?
When we talk about breathalysers, it is very unlikely that we are talking about a person who has agreed to test beer, liquor and the like. Rather, it is a device that is able to determine the alcohol content of a person.
Such a provision is of very great importance, especially in road traffic. If the alcohol content is above the limit, there is a risk of a driving ban, and fines.
A breathalyzer for private use can therefore at least roughly determine how high the personal alcohol content in the body is. If in doubt, the car, motorcycle or bicycle should always stop after drinking alcohol.
Digital alcohol tester - device for reliable measurements
People who rarely want to test breath alcohol can also use inexpensive disposable devices. However, a higher quality alcohol meter offers the advantage that the results are more accurate.
Electrochemical or semiconductor sensors analyze the breathing air within a few seconds and determine the blood alcohol level. So if you want to record the exact value, you are better off with such a breathalyser.
The small, handy testers are equipped with a blow tube fitted with sensors. In this way, the alcohol content in the blood is determined and displayed in the shortest possible time. If this exceeds the permissible value, a visual or acoustic warning is triggered on many devices.
How do we classify breathalysers?
Breath alcohol testing devices differ not only in design, size and weight, in the ease of use, compatibility with external devices such as printers or in different setting options. A very important distinguishing criterion for breathalyzers is the accuracy of their measurement results.
These in turn depend on the type of sensor installed. Basically, there are devices with a semiconductor sensor and those with an electrochemical sensor. Electrochemical sensors often work more precisely than those with semiconductors. Below we explain the differences between these two sensor types.
Alcohol Tester Breathalyzers
These are conductor devices used to detect presence of alcohol in air using sensor technologies.
Fuel Cell Alcohol Tester:
Fuel cell is a kind of electrochemical device which oxidizes ethyl alcohol and this process of oxidization generates a small amount of electrical current. This device is best to measure alcohol content and this reading is translated into BAC reading. Fuel cell can detect alcohol content in your breath for up to 24 hours via breathalyzer test.
These devices use electrochemical fuel cell which analyzes alcohol content in a breath sample. A fuel cell is made up of two platinum electrodes that are segregated by an acidic electrolyte material.
When you blow into a breathalyzer, alcohol content in breath is detected and oxidized by the platinum and acetic acid is produced as resultant, protons and electrons are also released. From the platinum electrodes, the released electrons start flowing through a wire and reveal the Blood Alcohol Content (BAC).
The strength of the current represents the volume of alcohol present in the breath sample. Stronger the current, Higher the BAC.
Fuel cells are advantageous as they possess high accuracy. Their working depends on the amount of voltage produces which is directly proportional to the content of alcohol present. They always remain responsive to alcohol only and won’t respond positive for diabetes. These sensors also do not need to be calibrated frequently.
Fuel cells have a single disadvantage that they’re very costly to purchase. They use platinum which makes them costly and expensive.
Semi-conductor Alcohol Tester:
It is an electronic oxidizer which oxidizes alcohol with a tin-oxide compound. Semi-conductors are small beads of metal oxide. A redox reaction is conducted at the sensor in the gadget by finding the alcohol concentration in the water particles emitted through breath. The resultant voltage provides quantitative results.
An initial small and standing voltage is applied to the sensor and when sensors detect alcohol particles in the breath sample, they change the surface resistivity of the metal oxide bean and the standing current fluctuates. The changes in current measure the amount of alcohol.
Semiconductor sensors are small bead like apparatus and they are not costly as fuel sensors. These devices are portable because of their simple apparatus.
Semi-conductors are not as reliable as fuel sensors as they are highly sensitive and produce false positives for compounds other than alcohols, like, mouthwash etc. External factors like diabetes, acid reflux, liver disease, gum disease can cause a failed breathalyzer. Semi-conductors are also short spanned and are unstable as they can easily get saturated.
MEMS Alcohol Tester:
MEMS, Micro Electromechanical System, are an alcohol detector sensor based on incorporation of microcircuits and micro machines. MEMS is an innovation to existing technology of semi-conductors.
When a person exhales and the breath containing alcohol molecules react with the sensing element, a change in physical phenomenon of device is seen. The detection of alcohol confirms through the change in resistance, capacitance, current flow, conductivity etc of the testing device.
MEMS sensor is accurate than semi-conductors and are closer to fuel cells. Moreover, MEMS produce stable results by comparative signal processing and increasing selectivity to target specific gases. MEMS consume less power than semi-conductors and the battery last longer than that of semi-conductor sensors.
MEMS is accurate than semiconductor and close to fuel cell. It is least expensive than fuel cell. Repeatability of MEMS is better than semiconductors.
Alcohol testers are mainly used by cops to detect alcohol addicts and mainly drunk drivers but these are easy to use as personal devices. One can have the suitable tester according to his budget and needs. It is necessary to acknowledge that all sensors work differently and come up of different compounds which react with different precisions.
If one is looking for accuracy and budget is not the hindrance than Fuel cell is the best option but if someone wants accuracy but the budget is limited, and then MEMS is the most suitable option. Semi-conductors are perfect if one is not too conscious about accuracy.
SZEEK is a company that specializes in manufactur-ing high-precision breathalyzers. We are the top manufacturer of breathalyzers in China. More