Is there a special name for keyboards that only have a few keys?

Background

I am building a custom embedded computer system and need only a few keys to be accessible by the users. I could attach a button board and program that in but was thinking it would be easier to just use and/or mod a 5 key keyboard. I have seen them before but cannot seem to find them online; it could be 6 keys as well preferably in a row.

Research

The closest thing I've found is chorded keyboards which are similar to what I'm looking for but rather expensive.

Question

Does anyone know what you call a keyboard that has only a few keys on it?

Updates

In response to the comments here are some clarifications:

• My project is a portable bluethooth and FM radio speaker.
• The embeded system is the Raspberry Pi Zero using the Zero4U to add USB ports.
• Bluetooth is added with a tiny USB dongle as well as the FM receiver.
• I need 6 keys preferably, 5 could work, in a row is the best.
• Something like the Cooler Master DIY Micro Keyboard is what I think I'll do.
• Googling Micro Keyboard or Macro Programmable Keyboard gives the best results.

I have found some awesome resources and ideas because of your answers. I will add these when I have time in an answer to help everyone else. I will also leave this question open for a bit to encourage more answers. This has become a great resource so please keep adding.

Solution 1:

From https://en.wikipedia.org/wiki/Computer_keyboard :

A keyboard with few keys is called a keypad.

https://en.wikipedia.org/wiki/Keypad:

A keypad is a set of buttons arranged in a block or "pad" which usually bear digits, symbols and usually a complete set of alphabetical letters. If it mostly contains numbers then it can also be called a numeric keypad.

If you have a few more keys, you could call it a 40%:

40% – Extremely small form factor with only the bare minimal of dedicated keys required to function. No alphanumeric keys, F-row or numpad. Many standard key operations will be hidden under multiple function layers. Some keys will be of a non-standard size.

Or alternatively, you could call it Apple Keyboard 2018.

Example:

Solution 2:

Why not simply get the standard 9-10 digit Numeric Keypad, cover up some of the buttons you don't use, and overlay a paper on top with actual buttons / instructions you do use? (Example as below):

This is the same method POS (Point of Sale) systems often used. They used a default keyboard, but pre-programmed each key for specific functions (or for adding pre-programmed items) and they overlayed the keyboard with a piece of paper (or maybe plastic-covered paper to make it somewhat water-resistant) with the correct program / function of the buttons.

If you want it to look better you can get your own custom-colored-printed-keycaps:

The reason what you wanted is expensive is because it is custom-built for a certain purpose. Anything that is not mass-produced is always more expensive.