This is a square-wave oscillator with a pulsing effect built into a vintage game controller.
The larger knob controls the frequency the smaller knob controls the speed of the on/off pulsing effect. The original momentary button is used to play the square-wave and the toggle switch starts the pulsing on and off. I also put in a neat vintage looking red LED.
Power and signal are connected through the original 3.5 ft. wire to a breakout box containing a 9v battery for power and standard 1/4 inch jack.
The square-wave has a classic lofi sound and when pulsing at high speeds you can get some really interesting throaty sounds.