Cherry MX Switch Breakout Hookup Guide

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Contributors: Jimb0
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Introduction

Cherry MX Keyswitches are top-of-the-line mechanical keyboard switches. They’re satisfyingly “clicky”, reliable up to tens-of-millions of key presses, and an essential component in gaming and programming keyboards. To help make the switches more easily adaptable to breadboard or perfboard-based projects, we created the SparkFun Cherry MX Switch Breakout.

Cherry MX Switch in action

In addition to breaking out the switch contacts to breadboard-compatible headers, the breakout also provides access to an optional switch-mounted LED. Plus, the pin break-outs are designed with keyboard matrix-ing in mind, so you can interconnect as many boards as you’d like into a row-column configuration, keeping the I/O-pin requirements as low as possible.

The Cherry MX Switch Breakout is a perfect prototyping tool for input devices ranging from a single key to fully-custom 101-key keyboards.

Covered In This Tutorial

This tutorial documents the SparkFun Cherry MX Switch Breakout, providing an overview of the breakout, plus some assembly and usage tips. It’s broken down into a few sections, which you can navigate around using the buttons on the right.

Or use these links below to skip ahead:

  1. Hardware Overview – A breakdown of the Cherry MX Switch Breakout Board features.
  2. Assembly Tips – Tips for adding headers, wires, resistors, and diodes to the breakout board.
  3. Testing the Circuit – A simple circuit to test the switch, LED, and any other components you may add on.
  4. Matrixing Breakouts – A guide to combining two or more breakout boards into a row/column matrix, and scanning them with an Arduino.

Bill of Materials

In addition to the Cherry MX Switch there are a few additional items you may want to add on to the Breakout Board.

3mm LEDs can be placed inside the switch. Pick any color you please: red, green, yellow, or cycling.

LED - 3mm Cycling RGB (slow)

LED - 3mm Cycling RGB (slow)

COM-11448
$0.50
LED - Basic Yellow 3mm

LED - Basic Yellow 3mm

COM-00532
$0.35
LED - Basic Green 3mm

LED - Basic Green 3mm

COM-09650
$0.35
1
LED - Basic Red 3mm

LED - Basic Red 3mm

COM-00533
$0.35

The breakout board also provides a footprint for an optional LED-current-limiting resistor. 1/6W PTH resistors, like these 330Ω’s, are recommended.

If you’re matrixing multiple breakout boards together, you may want to add a small-signal diode to the board to help isolate the switches and prevent any possible “ghosting”. Standard 1N4148 diodes should do the trick for this.

If you need to tie the board down, it has mounting holes designed to fit 2-56 screws and nuts.

Resistor 330 Ohm 1/6 Watt PTH - 20 pack

Resistor 330 Ohm 1/6 Watt PTH - 20 pack

COM-11507
$0.95
2
Diode Small Signal - 1N4148

Diode Small Signal - 1N4148

COM-08588
$0.15
Nut - Metal (2-56)

Nut - Metal (2-56)

PRT-08995
$0.15

Screw - Flat Head (3/8", 2-56)

PRT-08992
Retired

You’ll need soldering tools, including a soldering iron and solder. Other tools, like wire strippers, flush cutters, and a third hand, can also be helpful.

Wire Strippers - 30AWG (Hakko)

TOL-12630
3

Flush Cutters - Hakko

TOL-11952
17 Retired
Solder Lead Free - 15-gram Tube

Solder Lead Free - 15-gram Tube

TOL-09163
$3.50
2
Soldering Iron - 30W (US, 110V)

Soldering Iron - 30W (US, 110V)

TOL-09507
$9.95
6

Finally, headers or wire will help connect the breakout board to your breadboard or development platform.

Suggested Reading

This hookup guide relies on some beginner-level electronics knowledge. If any of the subjects below sound foreign to you, consider checking out that tutorial first:

Resistors

A tutorial on all things resistors. What is a resistor, how do they behave in parallel/series, decoding the resistor color codes, and resistor applications.

Diodes

A diode primer! Diode properties, types of diodes, and diode applications.

Switch Basics

A tutorial on electronics' most overlooked and underappreciated component: the switch! Here we explain the difference between momentary and maintained switches and what all those acronyms (NO, NC, SPDT, SPST, ...) stand for.

Light-Emitting Diodes (LEDs)

Learn the basics about LEDs as well as some more advanced topics to help you calculate requirements for projects containing many LEDs.