Switches Compared — Microswitches, Tact Switches, Navigation Switches, Rubber Domes and Hall Sensors, by the Datasheet

Force, travel, life and bounce from the makers' own sheets, and the number nobody checks: the minimum current a contact needs. A Pico's pull-up gives 41 to 66 µA; the 15 A microswitch a popular OpenFIRE build uses for its trigger asks for 160 mA

Figure 1 — A subminiature lever microswitch: a snap-action SPDT contact behind a hinged lever, with common, normally-open and normally-closed terminals. Arcade guns and most home-built light guns use one for … — Figure 1 — A subminiature lever microswitch: a snap-action SPDT contact behind a hinged lever, with common, normally-open and normally-closed terminals. Arcade guns and most home-built light guns use one for the trigger; in this build one sits behind the magazine catch and each of the levers. Photo: SparkFun Electronics, CC BY 2.0, via Wikimedia Commons.

3.1 Five Ways to Make a Button

Table 1 — 3.1 Five Ways to Make a Button

Family	How it works	Feel	Typical use in a light gun
Snap-action (“basic”, “micro”) switch	A pre-stressed spring blade flips the moving contact over at a set point and flips it back at a lower one	A distinct click at a fixed force; overtravel beyond it	Triggers, pedals, magazine catches, any lever
Tactile dome (“tact”) switch	A stamped metal dome collapses under a plunger and shorts two pads	A short, crisp click; very little travel	Side buttons, Start, Select
Navigation (multi-direction) switch	Several tact contacts under one tilting actuator, often with a centre press	A click in each direction	A D-pad on a small part
Conductive rubber dome	A moulded silicone dome with a carbon pill on its underside closes interleaved pads on a PCB	Soft, longer travel	Console controllers; the GunCon 2’s A, Start and Select
Hall-effect sensor	A magnet moves toward a sensor; there is no contact at all	Whatever the mechanism around it gives	The trigger (decision D8)

The firmware treats all of them the same way: a contact (or an open-drain output) to ground, read through the RP2040’s internal pull-up (Reference Electronics, Volume 4, §4.2). What separates them is feel, life, size and one electrical property that the firmware cannot see, taken up in 3.4.

3.2 Reading a Snap-Action Datasheet

A snap-action switch’s datasheet gives its mechanics as a set of positions and forces, and each one is a design input for the lever or button that drives it.

Figure 2 — Force against travel for a snap-action switch, schematic. Pressing, the force rises through the pretravel to the operating force at the operating position, where the contacts snap over and the forc… — Figure 2 — Force against travel for a snap-action switch, schematic. Pressing, the force rises through the pretravel to the operating force at the operating position, where the contacts snap over and the force drops; the plunger can then travel on through the overtravel to the total travel position. Releasing, the contacts snap back at the release position, which sits a movement differential short of the operating position. The panel at right lists the datasheet limits for the Omron V-15-1C25 and D2F-01F. Own work, from the Omron V and D2F datasheets.

Table 2 — 3.2 Reading a Snap-Action Datasheet

Term	Meaning	Why it matters on a gun
OF, operating force	force to make the switch operate (a maximum)	what the finger must overcome, added to any return spring in the lever
RF, releasing force	force below which it releases (a minimum)	the lever’s return spring must exceed it, or the switch sticks on
PT, pretravel	free position to operating position	slack before the click; on a trigger, the “take-up”
OT, overtravel	travel allowed past the operating point	the lever must stop inside it, or the switch is crushed
MD, movement differential	gap between operate and release	built-in hysteresis; the reason a snap-action switch does not chatter at the break point
OP, operating position	height at which it operates	sets where in the lever’s arc the click falls

The MD is the snap-action switch’s quiet virtue. A finger resting near the operating point cannot make it flicker, because releasing needs the plunger to come back a fixed distance (0.12 mm on the D2F pin plunger, 0.4 mm on the V-15). The Hall trigger has no such thing in its silicon and has to be given it in firmware (Reference Electronics, Volume 4, §4.6: press at 50 % of the span, release at 40 %).

3.3 The Parts Side by Side

All figures are from the makers’ own datasheets or product pages, read 2026-10-19.

Table 3 — 3.3 The Parts Side by Side

Part	Type	OF (max unless noted)	Travel	Mechanical life (min)	Contact	Minimum applicable load
Omron V-15-1C25	miniature basic, pin plunger, 15 A 250 VAC, #187 tabs	1.96 N	PT 1.2 mm max, OT 1.0 mm min, MD 0.4 mm max	50,000,000	silver alloy rivet, 1 mm gap	160 mA at 5 VDC
Omron D2F	ultra-subminiature, pin plunger, 3 A 125 VAC	1.47 N	PT 0.5, OT 0.25, MD 0.12 mm	1,000,000	silver alloy	100 mA at 5 VDC
Omron D2F-01F	the same, 0.1 A 30 VDC, low force	0.74 N	PT 0.5, OT 0.25, MD 0.12 mm	1,000,000 (electrical 100,000)	gold alloy	1 mA at 5 VDC
Omron D2F-01FL (hinge lever)	the same with a lever	0.25 N	OT 0.55, MD 0.5 mm	1,000,000	gold alloy	1 mA at 5 VDC
Omron SS-01	subminiature, 0.1 A	1.47 N (−F: 0.49, −E: 0.25)	per actuator	30,000,000	gold alloy crossbar	1 mA at 5 VDC
Omron B3F-1000	6 × 6 mm tact switch	0.98 ± 0.29 N	PT 0.25 +0.2/−0.1 mm	1,000,000	silver plated	10 µA at 1 VDC
Omron B3F-1002 / -1005	the same, firmer	1.47 / 2.55 N	0.25 mm	300,000 / 100,000	silver plated	10 µA at 1 VDC
Alps SKRHABE010	4-way + centre push, SMD, 7.35 × 7.5 × 1.8 mm	1.23 ± 0.69 N (directions), 2.35 ± 0.69 N (push)	0.25 mm (directions), 0.15 mm (push)	200,000 per direction and push	—	10 µA at 1 VDC
TI DRV5023 / DRV5056	Hall switch / linear sensor	none (contactless)	set by the mechanism	no contact to wear	—	— (powered: see Reference Electronics, Volume 4)

The V-15-1C25 is in the table because it is the trigger switch the PICON-AS OpenFIRE build names (Reference Electronics, Volume 4, §4.5). Decoding Omron’s model legend: V-15 is the 15 A rating, the 1 is SPDT, C2 is #187 quick-connect terminals and the final 5 is the 1.96 N operating force on a pin plunger. The SS-01 is there because it is what Namco fitted. The parts list in the Time Crisis SD operation manual gives the gun’s microswitch as “SS-01GL2T”: an SS-01 with a hinge roller lever (GL2) and #110 tabs (T), gold contacts.

Two bounce figures are published. The B3F’s datasheet gives “Bounce time 5 ms max.” The D2F’s sheet says “Close or open circuit of the contact is 1ms max”, but that sentence is the malfunction criterion for its vibration and shock ratings, not a bounce specification. None of the snap-action sheets read gives a bounce time. Volume 5 takes up what that means for the firmware.

3.4 The Minimum Current

Every Omron basic-switch datasheet carries a line most hobby builds never read: the minimum applicable load. For a silver contact it is 100 to 160 mA at 5 VDC; for the gold versions, 1 mA at 5 VDC. The D2F sheet states the consequence in its precautions: “Using a model for ordinary loads to open or close the contact of a micro load circuit may result in faulty contact. Use models that are designed for micro loads,” and describes the value as an “N-level reference value”, a reliability reference rather than a cliff.

A light-gun input runs at a tiny current. The RP2040’s internal pull-up is 50 to 80 kΩ (datasheet, GPIO electrical characteristics), so a closed switch carries 41 to 66 µA at 3.3 V.

Figure 3 — Each switch's minimum applicable load from its maker's datasheet, against the current an RP2040 internal pull-up supplies. The silver-contact microswitches, including the V-15-1C25, ask for 100 to … — Figure 3 — Each switch's minimum applicable load from its maker's datasheet, against the current an RP2040 internal pull-up supplies. The silver-contact microswitches, including the V-15-1C25, ask for 100 to 160 mA, more than two thousand times what the pin gives them. The gold-contact D2F-01 and SS-01 ask for 1 mA, still fifteen to twenty-five times more. Only the tact switch and the navigation switch are rated down to 10 µA. A 3.3 kΩ external pull-up raises the current to 1.0 mA, which meets the gold parts' reference. Own work.

Three conclusions follow.

A mains-rated microswitch is the wrong part for a light-gun input, however good it feels. The V-15-1C25 runs at roughly 1/2,400 to 1/3,900 of its minimum reference load on an internal pull-up. Silver contacts rely on current and contact force to break through the surface film they grow; at microamps there is neither. Such switches often work for a while; the datasheet simply does not promise that they will keep working. Reference Electronics, Volume 4, §4.5 already advises gold or “low level” contacts; the datasheets turn that advice into numbers.

Even the gold microswitches are below their reference on an internal pull-up. The gold D2F-01 and SS-01 are rated to 1 mA. Namco’s choice of a gold SS-01 for an arcade gun shows the right instinct, but an arcade I/O board’s input circuit is not the RP2040’s 50 kΩ pull-up.

The fix costs one resistor per microswitch. An external pull-up of 3.3 kΩ to 3.3 V gives 1.0 mA through a closed contact, which meets the gold parts’ reference value. Six microswitch inputs held closed together draw 6 mA, which is nothing on a USB-powered gun. The tact switches and the navigation switch need nothing; they are rated to 10 µA. This is a change to the reference circuit, which belongs to Reference Electronics, Volume 4; it is proposed here as decision-log row CI-3 (Volume 7) and not drawn into that volume’s schematic.

3.5 Tact Switches: Force Buys Feel and Costs Life

The Omron B3F family shows the trade every tact switch makes: a firmer click wears the dome out sooner. From the datasheet: 1,000,000 operations at 0.98 N, 300,000 at 1.47 N, 100,000 at 2.55 N and 50,000 at 4.9 N. (The long-life B3F-4000 and B3F-5000 lines push that to 3 million and 10 million.)

For a light gun’s A button, a sensible target is the light end. At one press every few seconds, a player who uses A heavily might press it a few thousand times in an evening; the 0.98 N part’s million operations are years of play. The firmer parts are better reserved for buttons that must resist the squeeze of a grip, which this layout avoids by placement instead (Volume 2, §2.8). A printed cap over the switch adds its own spring and travel, and in practice the cap, not the switch, decides the feel; the switch decides the click and the life.

The B3F-1000 is 4.3 mm tall with a flat plunger and is a through-hole part, which suits a small daughter board or a hand-wired switch glued into a printed boss. Its rating (1 to 50 mA, 3 to 24 VDC) and its 10 µA minimum mean it runs correctly on the internal pull-up.

3.6 One Part for the D-pad and Home

The Alps SKRHABE010 is a four-direction switch with a centre push in a 7.35 × 7.5 × 1.8 mm surface-mount body. Alps gives 1.23 N for the directions and 2.35 N for the push, so a thumb rolling across the directions does not press Home by accident: the centre press needs nearly twice the force. Travel is 0.25 mm in each direction and 0.15 mm on the push, which a printed cross-shaped cap can multiply into something a thumb can feel.

Its life, 200,000 operations per direction, is a fifth of the B3F-1000’s. That is fine for a D-pad used in menus; it would not be for a button used in play. Its rating (50 mA maximum, 10 µA minimum at 1 VDC) suits the internal pull-up. It is a surface-mount part, so it wants a small PCB under the receiver panel, connected to the carrier by the five-way JST PH lead Reference Electronics already allocates to the D-pad (Reference Electronics, Volume 4, §4.8), plus one more conductor for Home.

Alps sells this part by the 1,300-piece reel; LCSC sells single pieces (3.9).

3.7 Rubber Domes and Hall Sensors

Conductive rubber is what the GunCon 2 used for A, Start and Select (Modding Classic Light Guns, Volume 2 covers cleaning and repair). It needs a PCB with interleaved pads under every button and a moulded silicone sheet, both of which make sense for a production run on a custom board and not for a printed prototype. No rubber-dome datasheet was read for this volume, so no numbers are offered for it; it is not used in this build.

Hall-effect sensors remove the contact entirely. The trigger uses one by owner decision (D8), and Reference Electronics, Volume 4, §4.6 chooses the DRV5056A4 linear sensor with a DRV5023 switch as its stock-firmware stand-in. Using Hall sensors for every button is possible and is how “magnetic” keyboard switches work, but it costs a powered sensor, a magnet and a mechanism per button, and for buttons pressed a few thousand times a session the contact’s wear is not the limit. The trigger is different because it is pressed most, and because an analog reading lets its break point be set in firmware (Volume 4).

3.8 The Picks

Table 4 — 3.8 The Picks

Input	Pick	Why	Why not the others
Trigger	DRV5056A4 Hall sensor (Reference Electronics’ pick)	D8; no contact; break point in firmware; analog for a two-stage feel later (Volume 4)	A microswitch: wears, fixed break point; the V-15: fails 3.4 outright
Magazine catch (reload)	Omron D2F-01F, gold, pin plunger, 0.74 N	Gold contacts; low force, so the catch spring sets the feel; 0.12 mm MD stops chatter; 0.5 g body fits behind a printed catch	V-15: silver, 160 mA minimum, too big. SS-01: gold too, but larger and the stocked variant was out at LCSC. A tact switch: no overtravel for a lever that might be pushed hard
Selector (two contacts)	2 × D2F-01F on cams on the selector shaft	Same part as the catch; OT 0.25 mm absorbs cam tolerance	A rotary switch: no gold-contact part was found in a size that fits behind a selector; to revisit when the shell is drawn
Bolt-catch lever (B), charging handle (Start), stock lever (Select), pump end stop	D2F-01F	One part number for every lever: one bag of spares, one footprint (D11: kits)	Different parts per position: no gain
A (thumb button)	Omron B3F-1000, 0.98 N	Rated to 10 µA; 1 M life; crisp click under a printed cap	B3F-1002/-1005: shorter life for a firmness the cap can supply
D-pad and Home	Alps SKRHABE010	One part, five inputs; push force about twice the directions’, so Home is hard to hit by accident	Four tact switches under a printed cross: four parts, more holes, and Home needs a fifth
Pedal	the pedal’s own switch, through a jack (Volume 6)

Every microswitch pick (D2F-01F) gets a 3.3 kΩ external pull-up (3.4).

3.9 Where to Buy

Prices are from each seller’s own product page on 2026-10-19, in US dollars. DigiKey, Mouser, RS and TME pages refused automated reading, so their prices are not given; the part numbers are standard and stocked by all of them.

Table 5 — 3.9 Where to Buy

Part	Seller	Price (2026-10-19)	Stock shown	Link
Omron D2F-01F	LCSC C403989	$0.6446 each (1+); $0.5377 (10+)	926	https://www.lcsc.com/product-detail/C403989.html
Omron B3F-1000	LCSC C93157	$0.1874 each (minimum order 5)	6,500	https://www.lcsc.com/product-detail/C93157.html
Alps SKRHABE010	LCSC C139794	$0.78 each (1+); $0.6418 (10+)	7,313	https://www.lcsc.com/product-detail/C139794.html
Omron SS-01GL2 (for comparison)	LCSC C231399	$0.99 (1+), reference price	out of stock	https://lcsc.com/product-detail/Microswitches_Omron-Electronics-SS-01GL2-BY-OMI_C231399.html
TI DRV5056A4	see Reference Electronics, Volume 9

A first set for the printed gun is seven D2F-01F (catch, two on the selector, bolt catch, charging handle, stock lever, pump) plus spares, two B3F-1000 (A, left and right), and one SKRHABE010: about $9 at LCSC’s single-piece prices, before shipping.

3.10 What Could Not Be Verified

No snap-action datasheet read gives a bounce time; the B3F’s 5 ms is the only published bounce figure here.
Omron’s minimum applicable load is a reliability reference; no published failure data for gold or silver microswitches at 40 to 70 µA was found. The long-run test in 3.4 is the way to find out.
LCSC lists the SS-01GL2 as “SPST-NC”; Omron’s legend makes an SS-01GL2 an SPDT part. The listing is probably wrong.
Gaming-mouse microswitches (Omron’s D2FC family) are designed for low-current logic inputs, but their datasheet could not be retrieved for this volume, so none is compared.
No rubber-dome datasheet was read.

Sources

Omron, D2F Ultra Subminiature Basic Switch, Cat. No. B036-E1-12: model legend, contact specifications, characteristics, operating characteristics and precautions. https://omronfs.omron.com/en_US/ecb/products/pdf/en-d2f.pdf (read 2026-10-19).
Omron, V Miniature Basic Switch datasheet: model legend, contact specifications, characteristics, pin-plunger operating characteristics. https://omronfs.omron.com/en_US/ecb/products/pdf/en-v.pdf (read 2026-10-19).
Omron, SS Subminiature Basic Switch datasheet: model legend, contact specifications, characteristics. https://omronfs.omron.com/en_US/ecb/products/pdf/en-ss.pdf (read 2026-10-19).
Omron, B3F Tactile Switch datasheet: models, ratings, bounce time, durability, operating characteristics. https://omronfs.omron.com/en_US/ecb/products/pdf/en-b3f.pdf (read 2026-10-19).
Alps Alpine, SKRHABE010 product page, SKRH series. https://tech.alpsalpine.com/e/products/detail/SKRHABE010/ (read 2026-10-19).
Raspberry Pi Ltd, RP2040 Datasheet, GPIO pad control (SCHMITT) and electrical characteristics (pull-up resistance). Central Library text rp2040-datasheet (read 2026-10-19).
Namco, Time Crisis SD Operation Manual, §9-5 Gun Assy parts list. Central Library (read 2026-10-19).
LCSC product pages C403989, C93157, C139794 and C231399 (read 2026-10-19).