Tuesday, June 14, 2011

Making Light Work

Last week I said that I would show you how we wired the two Traintronics two-aspect, colour light signals that we recently added to the layout.
Well, true to my word, I am going to use this post to try and explain, as simply as I can, how we did it.
To begin with, the second diagram above shows how we wired our two signals. Of course, if you only have one signal, you can disregard the extra wiring for Signal 2. Similarly, if you have three or more signals, then you just need to repeat this extra wiring as many times as necessary.
Please note, though, that this diagram is only good for wiring the Traintronics two-aspect, colour light signals (TT102)  although, I daresay, the wiring for other makes of two-aspect signals will probably be much the same. However, if you are installing three or four-aspect signals or signals with feather lights, the wiring for those will definitely be different.
Please also be aware that this is for connecting the signals to a DC supply. If you wish to use them with DCC then this, again, will require different wiring.
The first picture, above, shows the Traintronics signal together with its printed circuit board (PCB). You also get a bag of bits that includes a ladder and hoop but I have not shown these as they have no bearing on the wiring.
As you can see there are wires (three in total) emanating from the bottom of the signal, these are coloured red, green and blue. Please be warned that they are extremely fine and great care must be taken when handling them. We actually slipped a length of protective sleeving over the wires and, also, over the part of the signal shaft that is inserted through the hole in the baseboard in order to give the wires some protection.
Once the signal is in situ and the PCB is attached to the underside of the baseboard, using the screws and spacers provided, the first delicate and fiddly job is to insert the wires from the signal into the three relevant screw terminals on the PCB. 
There are two groups of three terminals on either side of the PCB: one group is connected to the signal while the other group is connected to the supply.
The three connections for the signal are marked Blue, Red and Green, as per my diagram, so it is clear which wire goes where. However, the fineness of the wires, coupled with the fact that I was crawling around underneath the layout and it was dark, so a lamp was needed, meant that it was not the easiest of tasks to perform.
Once the signal wires are all securely inserted into each of the relevant terminals you then need to bring in two wires from the 12V DC supply and, for this, an old Hornby DC Train Controller is ideal. One of the wires from the supply (it does not matter which one) must be designated as positive while the other one is negative or 0V. 
The positive wire needs to be connected directly to the central pin or connector at the back of a double pole, single throw (ON-ON) toggle switch. This type of switch has two positions and, in both positions, the switch is ON - there is no OFF position. In other words, the switch will set the signal to either red or green.
Wires then need to be taken from each of the two outer connectors on the switch - with one wire going to the Red terminal in the 'From Supply' block of terminals on the Signal PCB and one wire going to the Green terminal. It does not matter which wire goes to which terminal.
Finally, the wire from the supply that has been designated as negative or 0V must be connected to the 0V connector on each of the Signal PCBs. We used a Terminal (chocolate block) Connector to split the connections between the Supply and the two terminals. However, if you have lots of signals, it might be better to use an adhesive copper strip, running underneath the layout, to which you can solder wires that, then, go to the switch and each of the terminals.
Once you are happy that all is connected properly it is just a matter of switching on the DC Supply and checking that the signals work. If they do then they should now be showing either red or green and, by flicking the switches up or down, so the signals should  change  from one colour to the other.

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