switches?

[krismosh]

This is my first DIY project so be gentle.  What kind of switches do I use for the matrix and what not?  I found a post saying that momentary off are used for the 5 in step A.  Does this remain true for the rest of the steps? Where's a good place to order the mini switches?  Finally can I use keys from a computer keyboard?  Thanks for any info.

[stryd_one]

Hey man welcome aboard :)

Momentary on switches are used everywhere. Where was that post?

A good place to order them really depends... Unfortunately there is no substitute for weeks of searching (or months if you're me)  if you want the best place, parts and price, but if you're not choosy, you can use the ones from your local electronics store, or yes, a keyboard - if it uses switches which can be removed, which most do not, or anything inbetween. It's up to you :)

[Wilba]

If you only need a few, then your local electronics shop or an on-line shop will suffice, like most electronic components, you can either pay a shop $1 for a part or find a distributor and buy 100 for $10. The little black ones you might see in other people's MIDIboxes (like TK's MIDIbox SID) are called tactile switches, they are either ALPS brand or a copy, and since they come in varying lengths of the "stem", you can mount them behind a panel with varying space between panel and PCB.

Using switches from a keyboard is also fine, just keep in mind most modern keyboards are made of rubber membranes over conductive "ink" on plastic! Not that easy to reuse! A really old keyboard with individual switches soldered to a PCB are good though.

[aeiou42]

Do you have any recomendation on what length to get for tactile switches? Most places i've looked at have 3 sizes. (actual length i can't remember) Would it be easier to just get long ones and then cut them to size? ...but then how wouls i cut them?

[Wilba]

I have tried cutting them, you can't cut them too close to the base as it's actually hollow for a few millimeters above the base with a narrow shaft inside the hollow section. If you're not looking for a perfect finish, you can cut them with a strong craft knife (we call them "Stanley" knives here) and sand the top.

But I would recommend not bothering with that and just get the length you need. Consider how thick your front panel will be, and how much space you need, things like rotary encoders need to be a certain distance behind the panel. Tactile switches only need about 0.5mm of travel, and can be easily pressed if poking out 1.5mm from a panel. So in my case, 13mm ones were good as I have a 10mm gap between panel and PCB, and the panel is 1.5mm thick.