Cherry MX Breakout Boards

Two breakout boards designed in KiCad. Both feature reverse-mounted addressable RGB LED LTST-A683CEGBW. Both are hot-swap capable (Kailh Socket / Mill-Max 7305). Total board dimensions: 26 x 19 mm.

Mill-Max 7305 holes are compatible with standalone switches so they can be soldered directly to the board.

Schematic	PCB (Kailh Socket)	PCB (Mill-Max 7305)

Kailh Socket Renders

Top View	Bottom View

Kailh Socket 3D Model was obtained from QMK. All credits go to them. The exact file can be found here.

Mill-Max 7305 Renders

Top View	Bottom View

Real Photos

Hooking up with Arduino

Code	Wiring diagram
#include "FastLED.h" const int ledPin = 6; const int buttonPin = 7; int ledHue = 0; const int ledSaturation = 255; const int ledBrightness = 255; CRGB leds[1]; void setup() { pinMode(buttonPin, INPUT_PULLUP); FastLED.addLeds<WS2811, ledPin>(leds, 1); } void loop() { if(digitalRead(buttonPin) == LOW) ledHue++; leds[0].setHSV(ledHue, ledSaturation, ledBrightness); FastLED.show(); }

What socket is right for me?

	Kailh Socket	Mill-Max 7305 & 0305
Cost per switch	$0.10 on kbdfans.com	about $0.88 on digikey.com
Requires compatible PCB?	Yes	No
Soldering difficulty	Both socket types are easy to solder and there shouldn't be any problems
General Notes	Kailh Sockets are much cheaper when it comes to custom builds but require custom PCB. Mill-Max connectors are not as stabilized as they make an extra gap between PCB and switch. Mill-Max 7305 is preferable over 0305, it's thinner so the gap is not that wide. Swapping switches seems easier using Kailh Sockets, Mill-Max connectors tend to bend sockets' pins. In my opinion, Mill-Max connectors should be taken into an account only when you modify pre-existing PCB as they have no advantage over Kailh Sockets and simply cost more

Datasheets

• Cherry MX
• LTST-A683CEGBW
• Kailh Socket
• Mill-Max