In this Instructable, I'll show you how to convert your ZX82 Spectrum keyboard into a functionally-expandable USB keyboard compatible with anything USB-enabled. This build is compact enough that when you're done, you can fit a Raspberry Pi or other small computer into the spectrum as well and just plug the keyboard in internally.
This build is nice and easy; I'll walk you through building the hardware interface to connect your Arduino to the Spectrum's keyboard membrane. Then we'll talk about how the software driver is constructed piece by piece, so it should be easy for you to customize later.
You will need:
- ZX82 Spectrum (doesn't need to be working) (x1)
- Arduino Leonardo or LeoStick (without soldered headers and preferably Leonardo for starting-out Arduino'ers) (x1)
- Arduino IDE
- 10KΩ (x5)
- Wire (x1 pack)
- Perf board / PCB (preferably tracked, approximately 30x45mm) (x2)
- USB A male-female extender cable (preferably short) (x1)
- Soldering iron, solder and solder sucker (desoldering pen)
- Masking tape
- Glue gun
- Multimeter or circuit tester