Customising your Switch

I got this switch sometime ago and well, since I had about 30 minutes of spare time, I decided to modify it. The main reason is that this switch has been made to light up with 12volts of AC power. Because Richard's 3volts project agreed to use this switch, I might as well be nice to him and have it lit. No point wasting the feature...

I love this switch. It comes in either momentarily (push to make contact) or latching (push-on, push-off). It also comes with or without a LED, double pole and also, you can rig it either as NO (push to ON) or NC (push to OFF). One last thing is, the lens can be in white too, apart from the usual red, green & blue which gives you a lot of modification. I'll tell you later.

This switch is quite long and so, you cannot just put
it anywhere you like. Not only that, I love pressing
on it because its so smooth and the click is very
satisfying. But remember, this is not an industrial
switch which means you cannot expect it to survive
thousands of presses in a day.

The first thing you must do, apart from buying the switch, is to remove the lens or the cap. You
can do this by gently pulling the cap until you see a small gap. Then insert your fingernail through the gap and gently pull the cap off. It will come off easily. If you have any resistance, don't force it but slowly do it as everything is plastic. Once you have remove the lens cap, you will see a tiny little circular assembly inside the switch. This is the LED for the switch and yes, it can be removed.

To remove the LED, all you have to do is to gently
rock it left and right with a screwdriver. You can
use a pair or tweezers or pliers but you will run
the risk of damaging the plastic holder, which is
very sensitive to force and heat.

Once the LED asssembly is out, please remember the orientation of the LED assembly as you will need to put it back again. LEDs are actually diode and they are polarity sensitive. Actually, in this case, you do not have to worry because, this strange plastic holder has a notch which only lets you slot it in one direction, which is good.

Just in case, I have marked it '+' because I saw the
sign at the solder tab. But it does not matter because
in reality, you need a multimeter to test the LED. Why?

This is why you need the miltimeter. The switch it was made to run at 12volts was because of the resistor and not only that, there is a diode too. In actual fact, this switch was to be used for 230volts AC while the LED is to light on 12volts AC. Not DC as I thought. The diode is to convert the AC into DC while the resistor is to being the voltage down to acceptable levels for the LED.

Because it has been soldered, and also there is no
marking to identify the polarity of the LED, you
really need to use the multimeter.

Using the desolder pump, you need to remove the excess solder as seen on the picture below. But you have to do this fast since the metal part is actually sitting on the plastic and the plastic melts very fast. So, you really need the desolder pump for the speedy job as you cannot remove the solder in any other way without melting the plastic. Once you have done this, gently remove the tiny plates but do not throw them as these are the contact plates that is vital for the LED to be connected to the switch.

You need something to hold the plastic while you
use the desolder pump. If not, the kickback from
the pump would push this thing away from your
table or worse, lose it. And when you desolder,
you have to do it fast as you do not want to melt
the plastic.

Do not throw these plates away!

Once the plates are kept in a safe place, you can now gently pull the LED out of the plastic casing. Or, you can just push the desoldered legs from the other end which can help push the LED out. What you need to do now is to replace the original resistor with that of another value. Note that the resistor is very small as it is a 1/8 watt resistor and not the usual 1/4 watt versions you buy from the Electronics shop.

I don't have the correct value, so I used the closest
(or next bigger) value, which is 68 Ohms. On hind-
sight, you can leave the diode alone. Now, use the
multimeter to make sure the LED is still OK. In this
picture, the resistor is soldered to the positive
leg of the LED.

Slowly attach the plates back to the plastic and
solder them. Again, do this fast so that the plastic
does not melt any further than it already is. Use
the multimeter to check that the LED is still OK.

Voila! All done. Check the LED with the multimeter
to see that it still works.

Remember I spoke earlier about the switch being very customisable? Well, here is another option. You can get some special 3mm LEDs such as blinking ones, RGB colours and so one, then get the same switch but with WHITE lens.

Why?

Imagine replacing the original red LED with the special 3mm ones. I did this when I was doing a CCTV tester where the same switch serves as an extra function of testing the CCTV's wiring. Green means wiring is correct, RED means Oh-oh.

Plug it back to the switch and test it again. Yes!

Put the lens cap back on and you're done.