What it does#
Electrically a key switch is just a button. The interesting part is how many there are: instead of one GPIO per key, keyboards use a matrix of rows and columns. A 60 % board (61 keys) needs 5 rows × 14 columns = 19 pins. The controller drives one column at a time and reads the rows.
The diode#
Every key gets its own small diode in series. Without them, three keys pressed in a rectangle make the fourth corner look pressed (“ghosting”).
Switch families#
| Family | Footprint in the catalog | Notes |
|---|---|---|
| Cherry MX and clones | MX soldered, MX hot-swap | 3-pin or 5-pin (2 extra plastic pegs) |
| MX/Alps hybrid | one footprint takes either | |
| Kailh Choc v1 / v2 | soldered or hot-swap | low profile; v1 and v2 keycaps differ |
| Alps / Matias | soldered |
Hot-swap sockets#
A Kailh-style socket is soldered to the back of the PCB; the switch’s pins push into it. Great for trying switches. The catalog’s MX socket is the HanElectricity CPG151101S11-16 (C41430893) on the Kailh footprint, because Kailh’s own socket was out of stock at JLCPCB; Choc sockets are not stocked there at all, so you solder those yourself.
Pitfalls#
- Diode direction must match the firmware (COL2ROW or ROW2COL).
- Hot-swap sockets need a plate or the switches pull the sockets off the board when you remove keycaps.
- Choc and MX spacing differ (18 × 17 mm vs 19.05 mm); the KLE import uses the switch you pick.
Footprint#
Switches themselves are hand-soldered (JLCPCB does not place them). Diodes and sockets can be assembled.