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I would appreciate help comparing the various tactile switch technologies towards achieving a soft feel, conveying quality to the user, while keeping costs and dev time down. These are to be used on front panels of scientific instruments.

This is what I have done so far:

We have tested Omron type of tactile switches 12x12mm (with and without caps) but the feel and sound are metallic and do not seem appropriate for the front panel of a high-end instrument. They feel and sound "cheap".

Metal domes seem to feel better but are often used with membrane overlays and conductive ink circuits on flex pcbs. Can this switches be used, which offer a nicer softer feel, on a regular PCB instead, placed behind an embossed or non-embossed membrane? No need to order a full customised membrane switch array then but we would buy and solder individual dome switches?

The ones we really liked though were the rubber switches (nice soft feel) but these seem to be manufactured as custom full key array products which require a mold and cost is likely to be high. Does the technology of rubber switches exist in discrete switches which we could buy individually and place/solder on a PCB, as we do with regular Omron 12x12 switches? Is this a viable way to avoid using molds and rubber injection/casting?

Overall the ideal answer to this question would be a suggestion on how to achieve soft feel and still keep production/prototyping costs and time low?

Thank you in advance

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  • \$\begingroup\$ Consider capacitive "switches". You can make them feel "soft" by placing a sponge material between the PCB and the key cap. E.g. BTC made PC keyboards in that technology years ago. \$\endgroup\$ – Janka Aug 18 '17 at 14:17
  • \$\begingroup\$ Interesting, there are many who go to great lengths to obtain the older mechanical switches used in the old IBM iconic keyboards of the 80s and 90s. For a soft feel, the cheap rubber domed switches in common keyboards sounds like the technology you are searching for. I should think you could buy a generic sheet of rubber domes and layout your PCB such that the contacts are under the domes. Then buy the plastic key caps. The tricky bit would be the case. You could laser cut or 3d print a prototype. \$\endgroup\$ – st2000 Aug 18 '17 at 14:19
  • \$\begingroup\$ There are suppliers that sell discrete membrane keys, even silicon ones. \$\endgroup\$ – Wesley Lee Aug 18 '17 at 15:33
  • \$\begingroup\$ I know this is going to sound silly, but how about enthusiast mech switches? Well defined stroke force, extreme reliability... for a soft feel I'd use these cherry switches (digikey.ca/product-detail/en/cherry-americas-llc/MX1A-C1NW/…) or the budget Gateron Reds (mechanicalkeyboards.com/shop/…) \$\endgroup\$ – 0xDBFB7 Aug 18 '17 at 15:40
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I found the magic Google search words are "long travel tactile switch" or "soft touch tactile switch".

The long travel, soft feel switches have rubber domes instead of the metal domes with travel typically 1.3 mm versus the metal dome switches often around 0.3 mm travel.

You can also get just the rubber domes if you want to build your own buttons into your enclosure such as if you're injection molding your own case.

This one has a nice video of how the buttons work: https://www.omron.com/ecb/products/sw/24/b3al.html

Whole pile of bare rubber dome buttons from China: https://www.aliexpress.com/cheap/cheap-rubber-button-switch.html

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