Hexadecimal 4 * 4 Keyboard Matrix
If you are into retro computing you may well have a device or system that requires hexadecimal input. This versatile Hexadecimal 4*4 Matrix Keypad could be a great fit for your user interface requirements! Many vintage computers, especially so-called “trainers”, used hex keypads as input. For example, boards like the Heathkit ET-3400 or National Semiconductors’ SC/MP development kit used hex keypads to directly enter memory contents — you had to do the assembly by hand!
This kit comes with all the parts to build a keyboard in a few differing configurations. It’s supplied with a batch of Cherry MX key switches, which, if you have delved into the world of DIY mechanical keyboards at all, you’ll probably know as being high-quality mechanical key switches with a large fanbase. There are a few options in the way that you can build the keyboard. You can opt for a simple switch matrix style, or with diodes to create a diode-protected keyboard matrix. The keyboard provides 16 keys for a full 0-F Hexadecimal input and there are two additional keys which are switched to ground that can be utilised as function keys. The keyboard output is via a standard pin header, so it leaves you with lots of options in terms of connectivity to your system. In fact, there would be nothing stopping you from combining this project with a microcontroller running QMK or KMK firmware and turning this into a modern macropad with a distinctly retro flavour!
It could also be used to refurbish old machines whose keypads are worn out or damaged. Most kits from the 1970s and 1980s used a few extra keys though, so you’d have to add a separate board with a few more switches depending on the configuration of the original. No matter what. we think this is a really neat board with a lot of applications! Check it out on the product page for more information.