What is it?

This is a budget 17 / 20 keys macro numpad that is powered by the CH552G MCU. This can be programmed using Arduino IDE with CH55x Arduino library. I have drafted a few ready-to-use templates that allow the 17 keys layout to act as a standard numpad and the 20 keys layout as numpad + media controller. You can also modify the templates to fit your needs or integrate it with Auto-hotkey for more advance use cases. See more on the open source Github page https://github.com/tobychui/4xMacropad

Technical Specification

17 keys / 20 keys layout

This PCB is designed to work with 17 keys standard numpad layout or 20 keys macropad layouts. There are two different firmware for each of the layouts on my Github repo. By default, I will flash the firmware for you according to the layout your purchased. However, if you want to change anything, you can also modify the open source template on my Github repo and flash it into the macropad yourself.

Arduino IDE Programming Notes

When you are programming this macropad with Arduino IDE, make sure to press and hold the PROG button on the PCB while plugging your macropad into your PC. This will prevent the IC from entering USB HID mode when it is powered on and allow Arduino to program it via UART.

Example Usage

• Basic macropad functions like automating key sequences, link with Auto-hotkey using F13-F24 etc
• Emulate Media Keyboard (e.g. Starting browser, calculator etc)
• Emulate Media Controller (For music playback, volume adjustment; Tested working with Windows + Browser Media Session API. See Github Example)

Why did you make it?

I notice there are a lot of mechanical numpad out there that cost around 40 - 60 USD for DIY kits and 80 - 90 USD for preassembled version. With prior experience in using the CH552G to made my own 4 keys macropad, I am trying to make another one that is cheap to manufacture and easy to program with Arduino IDE. It also help with my broadcast and video editing routine.

What makes it special?

This should be one of the most budget, programmable mechanical numpad options on the market. The whole project features a 3d print-able base, sample Arduino codes and everything is open source. Suitable for prosumers with some Arduino programming experience and want an extra macropad lying around to help automate stuffs.

All sale profits from this product will contribute to my next open source keyboard design in which I will also open source on Github. If you want to support my open source budget macropad / numpad project, you can purchase them here. If you have an even tighter budget, I strongly recommend you to build your own one as well! PCB Gerber files and required firmware source code are available on Github open source.

Notes to buyers

• The 3D printed case are printed with PLA with any materials I got left around. However, I will try to pick a color that best match the keycaps (if you pick an option with keycaps)
• Due to the hand made nature of this macropad, there might be some imperfections on the PCB (e.g. left over flux or slightly not aligned components on silk screen). Usually it is covered by the 3D printed case and not visible.