Micro Switch SW Series

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Micro Switch SW Series
Micro Switch Hall Effect single top view.JPG
Manufacturer Micro Switch
Introduced ca. 1968
Precedes Micro Switch SD Series
Supersedes Micro Switch SD Series
Switch type Linear
Sense method Hall effect
Keycap mount Micro Switch
Switch mount Metal clips
Patents US3596114 (1969)

Micro Switch SW Series (formerly referred to as First Generation Dual Magnet Honeywell Hall Effect) is a series of Hall effect keyboards and switches from Micro Switch.


The series name of "SW" is not 100% confirmed, but considering observed Micro Switch naming practice, the series name is likely to be correct, referring to both the keyboards and the switches. An eBay auction for NOS 1SW52-R red slider, angled keystem switches from 1987 contains a leaflet titled "Instruction Sheet SOLID STATE SWITCH MODULE REPLACEMENT" (MICRO SWITCH PK 8503 2),[1] offering the possibility that the series name was not always used; with that said, at that point it was not the only Hall effect switch available from Micro Switch.


According to Micro Switch, they introduced the "world's first solid-state keyboard" in 1968.[2] A patent was filed for the series in November 1969.

Based on the keyboard examples listed below, the known production range for SW series keyboards is 1970–1980. A similar list of examples isn't available for Micro Switch SD Series but it is likely that SW series was superseded by SD series somewhere around 1980.

SW series appears to have been followed by Micro Switch SN Series; comparing the Micro Switch SN/SD Series catalogue page with the switches sold by STRONIC in France appears to show three separate designs: SW, SN as depicted by Micro Switch, and SN as sold. One consistent difference between SW and SN is that the bottom of the shell in SN is not stepped as it is with SW; the retaining loop system is a different design and the shell sides are vertical at the base.

Components and durability

Hall Effect switches consist of a slider (with integrated magnets and spring), the switch housing (which is much harder than the slider -- this causes wear), and metal clips that act a plate to secure the switches. The metal clips determine what layouts are possible.Some Hall Effect switches are fully sealed against dust/debris to prevent dust from interfering with the capacitive matrix since a dirty PCB can affect switch sensing. Unsealed switches will function in bad conditions, but their press feel will be degraded due to grit.


Part no. Colour Angle Found in
1SW12-BL Black Straight IBM 3277 typewriter keyboard (1972)
1SW52-R Red Angled NOS (1987)

Removal and disassembly

You can remove a switch housing from a Hall sensor by bending its metal clips out a little (switches have a channel in them for a screwdriver). The disassembly process is relatively simple, making maintenance and cleaning easy. For reattaching the springs to the slider use the "chopstick" method; Twisting the spring one direction will tighten the spring twisting the other will open the end up a little. Twist to open the end and lightly push it in place.




  1. eBay — LOT OF 2 - Honeywell Microswitch 1SW52-R Solid State Switch Module replacement[Volatile reference]
  2. Internet Archive Wayback Machine — History (archived 1999-04-22)
  3. Flickr — Decision Data 8010 Punchcard Keyboard

External links