my ZX Spectrum hardware designs

Sparrow 48K (Speccy compatible mainboard - a spare part for original machines)

Bus expansion board for ZX Spectrum and compatible computers:

ZX ExpBoard

Interface boards - the "Simple" series:

Simple_AY_Interface (AY-3-8912 sound generator)

Simple_Joy_Interface (joystick interface, Kempston compatible)

Simple SAA Interface (SAA1099 sound generator)

Other texts:

What is the FADI initiative, what does mean the logo "FADI compliant"