I made this tiny contraption a while back this simple oscillator oscillates a frequency band form about 10k hertz to around 30k hertz.

Supplies

lm555 ic

15 microfarad capacitor .01 micro farad capacitor capacitor

10k variable resistor

speaker

Step 1: Pcb

We need to first design the pcb which I first did on paper then pcb123. Then I printed the circuit design on paper then I added the printer paper to the pcb which I etched with the help of an experienced adult. I scrubed the pcb after it sat in the etchent and put Isopropyl alcohol. You can skip this step and just make the circuit in kicad or eagle cad and than send it to pcbway.

Step 2: The Ic

This lm555 ic is a timer ic with a flip-flop we are going to use it to create an astable multi-vibrator that repeatedly triggers itself to create a clocking output we are going to use that to create an oscillating high frequency noise.

Step 3: Solder the Components

Solder the 555 ic, resistors, speaker and capacitors to the board add a 6 volt battery pack make sure that all components are soldered correctly if not a short circuit may occur frying your circuit.