Driver drinking detection circuit

Although car drivers and motorcycle users are not allowed to drive under the influence, it still happens from time to time. This circuit can detect the smell of alcohol
. The voice prompt "Don't drive after drinking" will sound immediately. When no alcohol odor is detected, a voice message of "Have a safe journey" will be emitted.
It serves as a reminder to warn drivers not to drive after drinking.
    (1)~ Tun circuit composition and principle circuit are shown in Figure 6H44. QM-NJ9 in the circuit is a wine sensitive sensor. After QM-NJ9 comes into contact with alcohol
, the resistance value between A and B decreases, and the potential of point B increases. The stronger the alcohol smell, the higher the potential of point B. This signal voltage
is taken out by the sliding arm of the sensitivity adjustment potentiometer RP and added to the ③ and ⑥ pins of the dual voltage comparator LM358. The reference voltage of the comparator ② and ⑤ pins
is determined by the voltage divider of the crown and R, that is, the ◎ and ⑤ pins The potential is fixed at V—Vcc/(R3 + R4)—1.47V. The two comparator inputs in LM358 are
connected in anti-phase. According to the principle of the voltage comparator, it can be seen that if the signal voltage on pins ③ and ⑥ is less than the 1.47V voltage set by pin ② and pin ⑤, the upper comparator
pin ① outputs a low level , and LED2 is cut off and does not light up. And the lower comparator ⑦ Royal base outputs high level. LED3 (green) is forward-biased, emits light, and triggers
the voice circuit TP-1106K at the same time. The speaker Y emits "I wish you a safe journey", indicating that the driver is here. '
    If the signal voltage on pins ③ and ⑥ is higher than 1. 47V, then the lower comparator pin ⑦ outputs low level, LED3 is cut off and does not light up. The upper comparator
pin ① outputs a high level, LEDZ (red) emits light, and triggers the ② pin TGl of TI--1106K. The speaker BL issues
a warning of "Don't drive after drinking", indicating that the driver's drinking exceeds the standard and should be forced to He stopped driving. The island is the filament FF current-limiting resistor of QM-I.U9, which
stabilizes the heating voltage at both ends of the filament at (5±oz)v, which ensures that the wine-sensitive element has high sensitivity and working stability. Because the alcohol-sensitive components
need to be preheated for 5-10 minutes before work . The detection can only be carried out after it is stable. At any time, one of the two comparators outputs a high level . In order to prevent the voice circuit from being accidentally triggered
, a manual switch S2 is set. When testing, just connect S2 and then let go. VD1 and VD2 are step-down diodes
. To ensure the appropriate power supply voltage for TP-1106K (2.5~4.5V). The timing components C and C can adjust the operating frequency of the voice circuit,
thereby changing the tone of the voice.