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Why $3 Macropad?
I have always been a great fans of Maker Faires around Asia and I am thinking if I could make something special so during maker events, I can exchange gifts with the makers I like so as to start a conversation with them. As a maker primarily working in the software and electronics fields, I really like the idea of PCB business card. However, most of the PCB business card ideas have already been done. From business card that play musics, light or mini game to the magical “My business card run linux” project. I want to come up with a new idea where no one have done before, yet cheap enough so I can afford to build a few of them and giving them out for free.

That is why I designed the “4xMacropad” - The business card size 4 key mechanical macropad. (Technically speaking the dimension is all “business card size” except the height)

Is it hard to make?
No. I strongly recommend this as your first “Tech Maker” project. This project contains the most basic elements of what a tech maker would usually use: PCB with SMT components, 3D printing and programming. There are a few advantage of this project as your first tech maker project

All components are hand solder-able, the smallest footprint is SOP, which is relatively easy packet in SMT world (compare to SSOP, QFN or even BGA)
Short working time: I can finish a board within 30 minutes :)
Low Cost: The material cost are just $3 (without shipping). This comfort many beginner who are afraid of breaking expensive ICs or parts.
Easy to program: I have already written a code generator / examples for you. You can pick up easily with little to no Arduino programming experience
So even if you are not used to working with SMT or programming, I still recommend you to give it a try :)

Lets get started!


- Custom PCB
- 3D Printed base (for mounting the PCB at a tilted angle)
- 4 M2 x 5 screws
- CH552G E8051 Arduino IDE programmable MCU
- Mode switch
- SMT button
- Mini USB port
- 7 x 0805 10k Ohm SMT resistors
- 2 x 0805 0.1uF SMT capacitor
- 3 x LEDs (Power, Mode A and Mode B)
- 4 x mechanical key switches
- 4 x key caps of your preference
- Soldering tools
- Steady hand”

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