DIY Kit MQ-3 Sensor Alcohol Detector Tester Alarm System Electronic Components SuiteSold By ICStation
★Wholesale Price can be offer for bulk order from 50pcs.
★Free Express Shipping (DHL/FedEx) can be offered for order reached $200 usd.
Please feel free to contact us if you are interested in it.
Description: This circuit is mainly an alarm control circuit formed by the gas sensor group MQ-3. When the sensor MQ-3 is in the environment where alcohol vapor exists, the conductivity of the sens...Read More…
This circuit is mainly an alarm control circuit formed by the gas sensor group MQ-3. When the sensor MQ-3 is in the environment where alcohol vapor exists, the conductivity of the sensor will be the same as the alcohol vapor concentration. By measuring the series partial pressure between the sensor and the fixed resistor, the alcohol content in the environment can be judged.
This circuit can be powered by 5-7.5V DC power supply, switch S1 is the power switch, resistor R1 and LED D1 are used for power indication. The internal sensor MQ3 needs to be heated to a certain temperature during operation, so its internal installation.
There is a heating wire, the resistor R4 is the current limiting resistor of the heating wire, and the heating of MQ-3 is normal after power-on. When MQ-3 does not detect alcohol vapor, its internal resistance is very large, the voltage drop of R3, RW is very low, the voltage of pin 2 of NE555 is lower than the trigger voltage (VCC/3), its 3 pin output is high level, D2 is extinguished. The buzzer does not sound and the relay does not move.
When MQ-3 detects alcohol vapor, the internal resistance decreases, the voltage of R3, RW rises, the voltage of pin 2 of NE555 is higher than the trigger voltage, the 3 pin becomes low level, D2 turns on the light, and the buzzer flows. The current starts to sound, and the electromagnetic coil in the relay energizes to attract the switch. Thereby implementing the detection alarm function.
The adjustable resistor RW is used to adjust the detection sensitivity. This circuit uses a second comparator inside the NE555 to detect voltage changes, using its internal trigger to debounce. The 7 and 5 feet of the NE555 are not used and are left floating. The output terminal J3 of the relay can be used to control other electrical appliances, such as exhaust fans.
When the alcohol concentration exceeds the standard, the exhaust fan is activated. After the concentration drops, the exhaust fan is turned off to realize automatic control. Diode D3 is used to eliminate the induced electromotive force generated when the relay coil is turned on and off. The power supply interface can be a DC plug, or the line can be directly at the J2 position, pay attention to the positive and negative signs, and the DC plug is internally and externally negative.
No country selected, please select your country to see shipping options.
No rates are available for shipping to .
Enter your email address if you'd like to be notified when DIY Kit MQ-3 Sensor Alcohol Detector Tester (13602 can be shipped to you:
Thanks! We'll let you know when the seller adds shipping rates for your country.
|Shipping Rate||Tracked||Ships From||First Item||Additional Items|
Free Express Shipping for Order Reached $200 usd. Thanks for Your Support!
We recognize our top users by making them a Tindarian. Tindarians have access to secret & unreleased features.
We look for the most active & best members of the Tindie community, and invite them to join. There isn't a selection process or form to fill out. The only way to become a Tindarian is by being a nice & active member of the Tindie community!