Best Master Caution Component?

[TigersharkBAS]

Hi gents,

For those who have implemented a UFC, what did you use for a master caution switch. Could you link to a part number or place you bought it please.

 

Also, anyone have links to a specific UFC build?

 

I'd like to learn how to mount microswitches and where they sourced the buttons etc.

[Stevos758]

I just picked up switches from ebay.

http://www.ebay.com/bhp/tactile-switch

 

I plan on CNC engraving my own PCB when I get time.

 

I was going to CNC the master caution button out of acrylic and just use a tactile switch.

 

I haven't had time to work on mine yet but have been gathering ideas lately. I have other projects ahead of this one.

[Devon Custard]

I designed my own project box, laser cut it and mounted simple tactile switches (from sourcingmap via Amazon) on matrix board. 100 x tactiles for £4!!

 

http://www.amazon.co.uk/10mm-Tactile-Tact-Button-Switch/dp/B008DS1HV2/ref=sr_1_1?ie=UTF8&qid=1400517837&sr=8-1&keywords=tactile+switch+10mm

 

Illuminated tactile for master caution from RS http://uk.rs-online.com/web/p/tactile-switches/6926999/

 

For the keys i reused the laser cutouts from the face plate and glued them to a piece of laser transparency. (thanks Tacno!)

 

I have a brydling B256 board so im simply passing the tactiles back to that and controlling the LED on the master caution via an arduino using the sketch you find on my tutorial.

[Warhog]

I am assuming you want these for the UFC of which there are approx. 32 of them.

 

The best way to mount these switches is on a PCB. I designed my own boards and drilled them out with a 0.030" dia drill bit or rather my CNC mill drilled them for me. The spacing of the tabs on the switches differ depending on which style of switch you purchase. So buy them before you design your board. Often there is a data sheet with them on eBay so you can see in advance the spacing. Also, the 12mm square switches are too large. When installed there is no room between them for LEDs so the 6mm square switches are what I am using.

 

I use 2 sided copper clad board. The back I will engrave traces for the switches. On the front I will engrave traces for the LEDs and surface mount them. SMDs are much easier to use then the standard 3mm or 5mm diameter LED. I use the 5050 Green SMD LEDS. Buy them from China. Excellent price.

 

http://www.ebay.com/itm/100-pcs-PLCC-6-5050-SMD-3-CHIPS-Green-9000mcd-LED-light-/121149856452

 

Buttons I cut and engrave on the CNC mill. Still looking for the best way to do this though for the best backlighting. I tried the switches that come with clear caps. Not very good for what we are doing. I believe the best way is to cut them from clear Lexan, leave a flange on the bottom and when cutting them leave tabs on all fours sides to keep them in place. Then spray them grey. When dry, engrave them which cuts through the paint and because the bottom of the button doesn't get painted it should transmit the light well. I do believe you would need to leave the back lighting on all the time though. You would be able to see the engraving that much better.

 

Here is something I am trying. I use double sided tape to hold the engraved plastic on to the Lexan button I milled. This way I have good transparency of the backlight through the button and the engraved plastic still shows white lettering until the backlight is turned on. Problem is how the sides will look once they are set into the face plate. Painting the side will definitely be problematic and is not a good solution.

 

 

I hesitate to put this next pic up as its a really shitty job but it does illustrate the SMD LEDS and the 12mm switches. I have learned to solder properly since that was built.:music_whistling: Now in this case there was a lot of room between switches but that is really the exception so don't use the larger switch.

 

Here is one of my latest creations. I place one on each side of my monitor for easy access to adjusting the radios and nav equipment. The buttons with the clear caps are on one of the strips so you can see what the effect is. Its OK for this application but unsuitable for a real panel.

 

 

One last comment that might help. If you intend to cut your own PCB, use the thickest copper clad board you can find as the thinner ones are way to flexible and offer little support to anything. And it does have a bias to it so it will always be slightly bent if you use the thinner boards.

 

I hope that offers some insight into your next project.