The heart of the circuit is an alcohol sensor, which features sensitive to the substances of alcohol. When we apply the power supply of 12 volts into point J1 then turn ON switch S1 to provided the voltage supply to this circuit. The voltage is maintained level of voltage constant of 5 volts by IC1-LM7805. This voltage will be feed into all power of
circuit.
The resistors R2 and VR1 serves to calibrate the voltage output from the sensor.More details, see the customization and the test projects.
When considering that sensor1 pin 2 and pin 5 will be parts of heating coils inside the sensor body. It will be connect with the positive voltage to ground makes generate heat up. The input of the sensor is pin 1 and pin 3 is connected to voltage as well. The output of the sensor is the input pin 4 and pin 6 is connected to pin 5 of IC2-LM3914. To apply the changes. From the sensors to manage with the
LED2-LED11. To measure the alcohol content From the breath the test on the sensor.
When who tester blowing Breathing that within the alcohol onto the sensor unit. The vapors of Alcohol into contact with semiconductor components in the sensor, the Resistance to change within the sensors. And have the output voltage to be applied to us. The heating coil will get rid of the alcohol vapor residues. Until the end From the first test. To ready for the next the test. For the first time after the calibration.
If you continue to drink more. Blood alcohol level of the drink will be higher.
Test by the volunteers drank beer cans, three and four cans. When again try blowing found that the dismissal order LED7-
LED11 will light up red. the test have shown that the level of alcohol too. Not suitable for driving any vehicle. Intoxication as a result of the slow and error. Should stop drinking and relaxing.