Shentong's taillights

Firstly, a 555 timer is used to generate a pulse signal with the frequency of 1Hz, which is used to provide the input signal for D triggering and braking. Three D flip-flops are used to generate three-terminal output cyclic signals of 00 1, 0 10 and 100, providing the original signal of turning left and right. Through the high and low potential signals provided by six AND gates and the electric key, the original signals of left turn and right turn are output to the left and right taillights respectively. This part of the circuit plays the role of signal sequencing. The sorted signals can be selected with brake and check key signals through OR gates. The final signal can be output to LED to realize the required function. Overall block diagram: Because the three indicator lights light up circularly when the car turns left or right, the ternary counter is used to control the decoding circuit to output low levels in turn, thus controlling the taillights to light up as required. From this, the relationship between each indicator lamp and each given condition (S 1, S0, CP, Q 1, Q0) is obtained, that is, the logical function table (as shown in Table 6-2 (0 in the table indicates that the lamp is off, and 1 indicates that the lamp is on). The overall block diagram of table 1 is as shown in the figure. Figure 1 Schematic block diagram of automobile taillight control circuit 1 Automobile taillight control logic menu switch control S 1 S0 ternary counter q 1q 0 Six indicator lights D6D5D41D30000000000165438. +000 00 100 00 00 100 00 00 00 1 1 00 00 100 00 00 10 00 00 10 00 00 00 0 10 00 00 0 / Kloc-0/0 000 000110 000 00011Circuit Design and Analysis 3. 2. 655438 According to the whole logic function table, G and A and the given conditions (S/Kloc) are obtained through analysis and combination. Switch control S 1 S0CP enable signal g000101kloc-0/11CP0cp table 2 S 1, S0, cp and g, a logic. The circuit diagram is shown in Figure 3. Design of decoding and display driving circuit of ternary counter 3.2.3 in fig. 3. The function of the decoding and display drive circuit is to provide six taillight control signals under the output of the switch control circuit and the state of the ternary counter. When the control signal output by the decoding driving circuit is low level, the corresponding indicator lamp lights up. Therefore, the decoding and display driving circuit can be composed of 74LS 138 (see table 3.3 for the function list), six NAND gates and six inverters, and the logic circuit is shown in figure 3. 10 (i). In the figure, the input terminals c, b and a of the decoder 74LS 138 are connected to K 1, Q 1 and Q0, respectively. When G=F= 1 and K 1=0 in the figure, the decoder output is 0 in turn for counter states Q 1Q0, 0 1 0, so that indicator lamps d 1, D2 and D3 correspond. When G=F= 1 and K 1= 1 in the figure, the decoder outputs are 0 in turn for the counter states Q 1Q0, 0 1 0, so that the indicator lights D4, D5 and d 6 correspond. When G=0 and F= 1 in the figure, all the decoder outputs are 1, so that all the inverter outputs corresponding to all the indicator lights are at high level, and all the indicator lights are turned off; When G=0 and F=cp in the figure, all indicator lights flash at the frequency of cp. Four different modes of taillight status display are realized. 3.3.4 Design of taillight circuit The taillight display drive circuit consists of six LEDs and six resistors. The output of inverter G 1-G3 is also 0 in turn, and the indicator light D 1→D2→D3 lights up in turn, indicating that the car is turning right. The output terminals of inverters G4 ~ G6 are 0 in turn, so the indicator lights D4→D5→D6 light up in turn, indicating the car to turn left. When G = 0 and A= 1, the output terminals of 74LSl38 are all 1, and the output terminals of G6 ~ G 1 are all 1, and the indicator lights are all off; When G = 0 and A = CP, the indicator light flashes at the frequency of CP. 3.3.5 second pulse circuit Design a multivibrator consisting of 555 timers; As shown in Figure 4, the circuit of multivibrator has large output driving current and flexible function due to the sensitivity of the internal comparator of 555 timer, and the influence of voltage and temperature on frequency is small. That is, the oscillation frequency of the multivibrator is stable. Figure 4. The installation and debugging of the pulse generator circuit 3.3 is shown in fig. 5. After the analysis of the above design contents and requirements, the circuit diagram of the automobile taillight controller can be shown in Figure 5. Firstly, a multivibrator composed of a 555 timer generates a pulse signal with the frequency of 1Hz, which is used to provide a ternary counter composed of double J-K flip-flops and a three-input NAND switch control circuit.