Sunday, October 24, 2010

DC Switches

I strained my shoulder yesterday hence no post. 

When pressed the switches in the canbus DC power distribution system merely send a pulse of electricity as a signal to the node. Unlike a conventional on/off switch the canbus switch has a ‘momentary action’. Essentially, they have a bell press mechanism. The advantage is that as they carry no load the wiring can be very light.  Data cable will do! For switches, I looked at a number of European manufacturers specialising in canbus systems.  Unfortunately all of them seemed very expensive. Then I realised the major Australian manufacturer of AC switches and sockets was located in our home city. A quick check of the Clipsal website showed they had an propriety AC canbus system named “C-Bus”. After looking at their ‘Saturn’ range of switches we decided we liked the ‘Ocean Mist’ faceplates with the LED backlight switches.

Light switch 7

The problem was the LED’s were 240v AC and we would have a 12v DC system. The switch mechanism would work but the LED would not illuminate using 12v. Could I disassemble the switch and convert it to 12v DC.  The local distributor was able to sell me one switch which I disassembled. The short answers is “Yes”! I pulled the switch apart and replace the existing LED and printed circuit board with a small LED and resistor. The switch comes with a warm blue light which I can replicate. However I can also fit another coloured LED inside the switch if desired. So I’ve decided the light switches will have a blue LED and all other switch will have a red LED. The LED is activated when the switch is pressed on.

My first effort resulted in too much illumination leading to ‘bleeding’ around the button

Switch with clear top & red LED copy

A second attempt achieved a better result

Black top switch illuminated

All I now have to do is disassemble and modify another 32 switches!

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