4 oscillator synth with an Atari Joystick

Yet another variation on the 4093 oscillator design, this one uses 4 directions of the stick for patching the outputs from off to on. The pitch of each oscillator is controlled by a knob and can be adjusted in realtime of course. The patching is not as easy as it seems because the resistors in the circuit can’t be switched in and out, instead I am basically switching the 1uF capacitors to the ground in order to engage the oscillators. In other words, since all the 1.0 uF capacitors in the circuit run to the ground, the joystick common was set to ground and the capacitor minus leads were soldered to the directional pins on the port. The fire button patches another 10uF capacitor in the circuit to one of the oscillators, creating a drastic pitch change. Quite a few shots of the insides and the building process are available on GetLofi gallery. The last image is also a video link, sounds good for such a simple circuit, especially once the delay kicks in.