As you know, Sinclair ZX Spectrum doesn't have a joystick port. This is an unpleasant situation for retro gamers. I searched for a joystick interface for the Sinclair ZX Spectrum that I was restored and found Yarek's joystick interface project. I added a reset button to this beautiful project. As seen in the pictures, the pcb is a homebrew and working circuit. Problems that may arise after fabrication are at your own risk.

Have fun....

Bill of materials:

1 x 74LS32

1 x 74LS240

8 x 8.2k Resistors

1 x DB9 Male Connector

1 x Tactile Button

1 x Female Edge Connector (You can use PC ISA slots by revising them.)