magnifier
Language
  • English
Currency

DIY Kit MQ-3 Sensor Alcohol Detector Tester Alarm System Electronic KIT

In stock
Description: Alcohol concentration alarm circuit 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...
$8.63
$8.63
  customers are viewing this product

Description:
Alcohol concentration alarm circuit 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. Increase and increase. By measuring the series partial pressure between the sensor and the fixed resistor, the alcohol content in the environment can be judged.

Working voltage: 5-7.5V DC

Circuit Description:
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 denounce. 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.

Package Included:
1 x DIY Kit MQ-3 Sensor Alcohol Detector Tester Alarm System Electronic KIT (require assembly/soldering)
Instructions/schematic are NOT included. We don't provide technical assistance please make sure that you are familiar with the product before purchasing.

Returns Policy

You may return most new, unopened items within 30 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the 'Complete Orders' link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.

Shipping

We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.

When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.

Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.