Tuesday, 2 November 2010

Modifying the Boat Light Switches

You may recall an earlier post where I wrote about modifying the 240v light switches from Clipsal Australia to work on 12v DC.  The problem with the switch was the inbuilt LED indicator would only worked on 240v.

The first switch I purchased from Clipsal came with the LED on a printed circuit board mounted inside the switch.

Light switch 2

My initial idea was to remove the printed circuit board and replace it with a 5mm LED.  Then I realised there was another similar model of switch without the LED.  I guessed the second switch would be similar except there would be no printed circuit board.  And I was almost right!  Both models had the same chassis however the second switch didn’t have a clear plastic top.

Light switch 1 

In the photo above, top left, is the assembled switch containing the LED on the printed circuit board.  You can see it has a clear plastic top.  The switch without the LED has been disassembled and at the top right of the photo the cap has a solid black plastic top.  Obviously light from a LED inside the switch won’t penetrate the black top.

What I’ve done is to drill holes in the black top using a fine drill bit.  The idea is to allow some light to pass through the top.

Light switch 4

In the next photo you can see I’ve been able to fit a 5mm LED into the right compartment.  This is where the printed circuit board normally fits.

Light switch 5

I then reassembled the switch (with some difficulty I might add!) and soldered a resistor to one lead to reduce the 12v down to 2.5v.

Light switch 6 

As you can see in the following photo’s the blue light with the black top is acceptable, however the red light through the clear top is too bright.

Light switch 7Light switch 8

The options were to either utilise the black top switch or place an additional resistor in the lead to the red switch to further reduce the voltage and by default the illumination. 

In the end I haven’t needed to adopt either of the options as the clever people at Atlantis Marine were able to modify the printed circuit board thereby enabling the existing switch to be used.  Thank you Mark Zimmerman!

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