You can make this typical 555 timer oscillator square wave oscillator circuit.

This Instructable shows you can use the 555 timer to power light bulbs and speakers.

The first two videos show the circuit connected to the light bulb and speaker. The last video shows all the photos of this instructable with music that you can watch instead of reading this instructable.

You can click on this link to learn about 555 timer oscillators.

https://www.allaboutcircuits.com/tools/555-timer-astable-circuit

Supplies

Components: 1 kohm resistor - 2, 1 Megohm potentiometer or variable resistor, two 555 Timer ICs (in case you damage one), wire wrap socket (8 pin), matrix board, wire wrap wire, SPST (single pole single throw) or SPDT (single pole double throw) switch, 470 nF pillow capacitor, 22 nF ceramic capacitor, 10 nF ceramic capacitor - 2, wires.

You can use one 33 nF capacitor instead of 10 nF and 22 nF capacitors. I just made a circuit from what I had in stock and what was available at the local electronics shop.

Tools, wire wrap tool, wire stripper.

Optional components: solder.

Optional tools: multimeter, USB oscilloscope, soldering iron (to solder wires to switches)

Step 1: Design the Circuit

The oscillation frequency is equal to:

f = 1.44 / ((R1+2×(R2a+R2b)) × C)

(Where: C = C1a + C1b or C = C2)

From the formula above you can see that: the higher the resistance and the higher the capacitance, the lower is the output frequency.

(because the capacitance of parallel capacitors is equal to the sum of all capacitors)

I used a maximum capacitor of 470 nF to avoid using electrolytic capacitors.

If you use a selector switch (both switches are NOT ON at the same time) then:

The minimum frequency will equal to: f = 1.44 / (2003000×(470*10^-9)) = 1.5296 Hz

The maximum frequency will equal to: f = 1.44 / (3000×(32*10^-9)) = 15,000 Hz = 15 kHz

If you are using a 4 ohm speaker then the lower bandpass frequency will equal to:

fl = 1/(2*pi*4*(1000*10^-6)) = 39.7887 Hz.

The frequency must be below 20 Hz. However, 39.7887 Hz is also okay. If you use 470 uF capacitor the lower bandpass frequency will equal to 84.6569 Hz.

Step 2: Simulations

I used PSpice software student edition version 9.1 for simulations.

The first graph shows low frequency. The second graph shows the maximum frequency.

Because R2b is set to 500 kohm (not 1 Megohm) the frequency of the signal that you see in the first graph is not the minimum possible frequency.

Step 3: Make the Circuit

I only used the soldering iron to connect the wires to SPDT switch. I used the SPDT switch as a selector switch. Thus the capacitors C1a/C1b pair and C2 capacitors are not connected at the same time.

You can replace the Sw1 with a short circuit and use SPST for Sw2 switch. You will get similar results, except the minimum oscillation frequency will be slightly lower.

PSpice software student edition did not have the SPDT component. When SPDT component is in the middle the circuit oscillates at the highest frequency because none of the capacitors are connected.