What is it?

MG004 is a USB numeric keyboard designed for Cherry mechanical switches (or third party equivalents with the same form factor). It consists of a PCB, with all components except switches,keycaps and LEDs already soldered on.

What do I need to add?

Buyers will need to supply:

• Switches. There are many on the market to choose from, with different actions and prices
• Keycaps. Similarly, many different colours, fonts and even shapes can be bought or even 3d printed
• Mini (not micro) USB lead. You probably have a mini USB lead somewhere, if not they are available on the likes of eBay

What don't I need to add?

Buyers will not have the expense of an Arduino or similar microcontroller card, as the ATMEGA32U4 microcontroller is soldered in and pre-programmed for the price. It can be reprogrammed (using the standard Arduino IDE) to accommodate different keys.

What extras can I add?

There are a couple of things buyers can buy and add to personalise their keyboard (beyond the choice of switches and keycaps):

• LEDs. Standard 3mm LEDs can be soldered in to backlight the keycaps (they will shine through any translucent parts of the keycap)
• A case (housing). I think my keyboard looks great "naked", with some self adhesive feet stick on the bottom. You might not agree, if so, this is a relatively easy shape to 3d print a case for.
• Stabilisers for the 2u (bigger) switches. They're not as easy to get as the switches, but Cherry (for example) provide stabilisers to make the 2u switch action nicer if pressed off centre. The PCB has holes for Cherry stabilisers ready drilled.

Why did you make it?

Because many keyboards nowadays do not feature a numeric keypad (including mine). And I really like mechanical keyboards....

What makes it special?

The fact that under the skin it's really an Arduino clone, which can be reprogrammed over USB easily to accommodate different key functions.

What else do I need to know?

I have added a photo to the listing to give an idea of what the completed kit looks like, once some typical user supplied switches, keycaps and LEDs have been added.

Full instructions are provided at the link below, including dimensions needed to mount this is in a housing.

MG004 used the SparkFun Pro Micro as a starting point for development. The Pro Micro was developed by SparkFun Electronics, based on an original design by Team Arduino. The MG004 circuit schematic is released under Creative Commons Attribution-ShareAlike 3.0 (https://creativecommons.org/licenses/by-sa/3.0/).

MG004 has been designed for hobbyist use only and is not to be used for safety or business critical applications. The kit assumes basic through-hole soldering skills.

The payment of any import taxes and duties will be the responsibility of the Buyer.