Specifications

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Figure 2.10-1: MQ-3 Alcohol Sensor, Reproduced with permission from:
Sparkfun.com
Figure 2.10-2: Standard MQ3 alcohol configuration. Reproduced with permission
granted by: HANWEI ELECTRONICS CO.,LTD
The major concern of this sensor model is its reliability and sensitivity, although it
is the most commonly used sensor and marketed as “High sensitivity” and
“Stable and long life”, it is still a low-end sensor, but it certainly has its advantage
as well. Being the most common sensor, its availability is not an issue and its
price, cheapest in comparison. With the uncertainty of its reliability and sensitive,
we have created a primitive option to our future design with an easy sensor-
swapping module. This will take ease in the need of re-calibration due to uses at
the cheap replacement cost of the sensors.
MR-513
A very similar in appearance design compared to the previous MQ-3, but not so
much internally, thus poses its own advantages. MR-513 utilizes the wheatstone
bridge circuit design and are able to detect both element (alcohol) and
compensation element (sensor and ambient temperature). As a result, it is a
better sensor compared to the MQ-3. An visual is provided in Figure 2.10-3.