On-campus tryout 555 sounder

First choice question
A: Specific requirements for 555 sound generator: Use NE555 to complete the production of a sound generator, which can controlly emit a total of 8 tones from midrange C (1) to high pitch C (1). USB or battery powered. I hope that the circuit is as simple as possible, as controllable as possible, the sound effect is as good as possible, and the sound is produced as much as possible. (Sound frequency; control method is not required)
2. Design process
1. Find the frequency corresponding to the tone, and take a total of eight frequencies of alto and treble 1.
2 Find the corresponding information, enter the frequency and duty cycle to calculate the values ​​of R1, R2 and C.
 
3 Calculation results are simulated using proteus. After simulation, it is found that the sound with a lower duty cycle vibrates slightly. The following table data is the data with a duty cycle of 10%.
The simulation diagram and a waveform diagram are as follows.
Simply calculate f=529.1≈523Hz.
4 Next, find the corresponding components in Lichuang Mall and draw the schematic diagram. The list is shown below. The two potentiometer packages are the same.
The schematic diagram is as follows
5. Draw the PCB (1) layout diagram.
After adjustment, the layout is more compact. The buttons are at the bottom and to the left for easy adjustment. The buzzer and DC005 interface are close to the outer end for easy carding. (The left side is below) The lines look messy but do not affect multi-layer wiring.
(2) The wiring diagram is as follows.
The normal line width is 0.26mm and the line spacing is 0.2mm. The line width of power terminal U1_4 is 0.4, the line spacing is 0.4, and ground U1_1 is ignored.
(3) Copper laying diagram (front and back)
 
(4) Simulation of the actual picture
Three thoughts:
This circuit adds a lot of resistors and a set of switches to make the duty cycle almost the same. The circuit principle is simple but the components are difficult to find, so the optical power supply was changed. Three times, the battery box was too big and took up space. It was difficult to solder USB and I couldn’t find the interface at home. I found the interface of DC005 and finally selected DC005. It can be seen that the design process is not just as simple as principle simulation. Material selection and layout are also very important.
 
    The buzzer sound will be a little jittery, which may be due to improper capacitance or duty cycle. Wait for debugging after the finished product is made.