Audio toy car circuit diagram

After the power is turned on, the car will move forward, the front car lights will be on, the car will make a loud police car sound, and the red light on the roof will flash; when the car encounters an obstacle, it will reverse and turn, the rear car lights will be on, and the front car will The light goes out and the sound turns into a pleasant "ding-dong, ding-dong" double tone; after reversing for 3 to 4 seconds, it can automatically resume straight forward; if it encounters another obstacle while reversing, it can immediately change to straight forward. S1 and S2 are power switches; LED4 and LED5 are headlights; LED6 and LED7 are rear lights; SB1 and SB2 are front and rear touch switches respectively. The length of reversing time mainly depends on the time constants of R1 and C1 and the magnification of VT1. In the figure, it is 3 to 4 seconds.