Electronic Lucky Turntable

Function: The Lucky Turner is a tool that first predicts where the disc will stop when it stops. Can also be used as an estimate number game, electronic dice, lottery machine, etc. The electronic lucky turntable achieves the same function electronically. This kit configures 10 LEDs into a circle. When the button is pressed, each LED rotates in sequence. At the beginning, the flow speed is very fast. It looks like all the LEDs. As if all flashing together, the flow speed will be slower and slower, and finally stop moving on a certain LED. If the last LED is the same as the player predicted, it means "winning".

Circuit principle: The circuit is mainly composed of a pulse generator and a decimal counter circuit. The pulse generator consists of NE555 and peripheral components. The multi-vibrator is composed. When the button S1 is pressed, Q1 is turned on, and the NE555's 3 pins output pulses. The 10 outputs of the CD4017 alternately output high-level driving 10 LEDs to rotate. After releasing the button, Q1 will not be cut off immediately due to the presence of capacitor C2. As the voltage across C2 decreases, the conduction procedure of Q1 gradually weakens, the frequency of the output pulse of 3 pin becomes slower, and the frequency of LED movement also follows. Slow down. Finally, when the C2 discharge is over. When Q1 is cut off, the NE555's 3 feet no longer output pulses, and the LED stops moving. A "winning" process was completed. R2 determines the speed of LED movement, and C1 decides the time to wait for the "winning".

Schematic:

Component list:

Common Problem:

1.电阻焊错，注意板子上的标识，两个的是470K，一个的是10K。

2.电解电容容值和正负极没有注意，一个47uf，一个1uf，长脚正极。

3.1N4007方向焊反，有白色的一边对应板子上有横杠的一边。

4.芯片插反，注意芯片缺口对应板子上标识缺口的方向。

5.LED正负极，长脚正极。

6.电源接反，VCC接正极，GND接负极，供电电压要3-6V直流电压。

Appendix: Specific identification methods for four-ring and five-ring color ring resistors