oh for a reliable button

[philba]

I have a door intercom for which I paid rediculous amounts of money 4 years ago. (it's pretty, ok?)

The spmom button is flakey on it - works about 20% of time. sigh. The site is sheltered from the weather but this is the wet and rainy pacific northwest so it sees some condensing humidity. I want to replace this button with something that will last a little (ok, a LOT) longer than 4 years so I don't want to get Holosound's replacement (plus it's through a distributor who want's to install it and charge a min of $75 for a visit - nfw).

So, anyone have any recommendations for a reliable switch? The hole appears to be 5/8". I don't need anything fancy, just ultra reliability in the face of high humidity. The usage is pretty low - 3-5 times a week max. I don't want to change the design or build a fancy hall effect device - just a reliable mechanical switch.

Thanks!

Phil

[Edd]

HEEEEEY Philba:

KJR Seattle…channel 95…during my Northwest country days…

If it’s the type of switch that can be disassembled and is the normal momentary contact.
(The small Tact switches are not good enough to qualify...but)
How about a disassembly and a good non metal aggressive, yet a very smooth burnishing of its contact surfacing area and a final healthy blob of Corning Z-5 silicone grease encasement to eliminate future , oxidation, moisture and lastly, its loss via heat sag.

73's de Edd
[email protected] .........(Interstellar~~~~Warp~~~Speed)
[email protected].........(Firewalled*Spam*Cookies*Crumbs)


<small>[ November 09, 2005, 03:35 PM: Message edited by: Edd Whatley ]</small>

[josmith]

http://content.honeywell.com/sensing/pr ... cswitches/
I heard a story about a P-40 (crashed ww2 aircraft)that was recovered from the jungle after 40 years. The micro switch on the landing gear still worked.

[k7elp60]

I understand you are looking for a pushbutton.
I have had good luck with Switchcraft momentary push buttons. Numbers 912, and 913. The number determines the color of the button, black or red.
Mouser Electronics stocks them. Part number 502-912 or 502-913. They mount in a 1/2" hole so you may have to use some fender washers, but the mounting bushing is fairly long for thick panels.

[Robert Reed]

I like the P-40 story--thats when things were over designed and built to last! Now a days everything is so minaturized that they seem to wear out quicker and overall products are not designed to last . Due to this fast moving hi tech age, they are almost obsolete by the time the last one comes off the assembly line.
Philba
Have you looked at industrial grade machine switches. Pricey- but forever. I also like Edds reply if you can get yours apart.

<small>[ November 09, 2005, 05:26 PM: Message edited by: ROBERT REED ]</small>

[rshayes]

I am partial to the C & K pushbutton switches such as the 8020 series for low level switches. They have a fairly light snap action with light pressure and gold plated contacts. They won't handle much power since the gold plating burns off at currents over a few milliamps. Jameco appears to sell these.

Some old keyboards used reed switches with a moving permanent. The reed assembly was a hermetically sealed glass case. These would be very resistant to moisture but probably take a long distance to actuate.

The old World War II microswitches weren't hermetically sealed. The case was phenolic, which is slightly permeable to water vapor. They did use rubbber sealing gaskets, which is still a lot better than most other switches.

Some later microswitches actually enclosed the contacts in a hermetically sealed metal case. A flexible metal disk was used to transmit the actuating force to the contacts. These are probably very rare.

[Chris Smith]

Try a Brass gong, isolate the bell and handle, so when they touch with a loud bang, they also contact your electrical circiut. Should one fail, the other wont?

[philba]

Hey, Thanks guys. I appreciate the responses. Guess I will order several different ones and give them a try. At a couple bucks each, I'm way ahead of holovoice.

The switch is a fairly cheap looking sealed unit. What's amazing (read: what is pissing me off) is how and where the circuit board is held in place. Double sided tape to the speaker frame. sheesh. I paid for that crap? If the front plate wasn't really nice antiqued solid brass, 1/4" thick, I'd junk it.

[Gorgon]

Hi Philba,
I don't know if this is outside the subject, but what about a reedswitch and a magnet on the pushbutton. The reedswitch operates with goldplated contacts in a protected atmosphere and should last for years. One problem may be the geometrics of your panel, those I don't know.
I work in the firealarm business and we use magnets to test the detectors. Inside the detectors are small reedswitches.

TOK

[jollyrgr]

I'm not sure of your space constraints but the best bang for the buck is the microswitch. I've also heard them called snap action and "Cherry" switches. They make momentary push button panel mounts as well as lever activated. For a push button style see this example:

http://www.allelectronics.com/cgi-bin/c ... type=store

There are also the "JUMBO" push button switches that you find on Arcade style video games. These have to be one of the toughest switches I've ever seen. Go to this site and scroll to the bottom of the page. See "page two" at this location for more examples.

http://www.allelectronics.com/cgi-bin/c ... type=store

[Enzo]

I too was going to recommend that Jumbo switch. I had no idea All Elex was selling them, I was thinking more along the lines of Happ COntrols, but who cares where you get them. That price is reasonable.

By the way, the miscroswitch just snaps in and out of those in a half second for service or making connections etc.

I have been in the arcade industry for many years, as well as the pro audio world I mainly exist in now. I use those for foot switches, and they hold up wonderfully. Doorbell use would be no stress on it at all.

Of course you would have this big inch and a third sized button. Mounts in 1-1/8" hole.

Even if not for this project, they are very cool tough switches for something.