Recently I wrote here about building some signal kits and also about hearing of the release of Dapol’s 7mm (1:43.5) ready-to-plant signals. The signal I’ll be talking about here is the GWR wooden post semaphore (item #7L-001-00) which was provided to me by ModelOKits for evaluation. I’ll write a full review of this and the LMS tubular post signal in an upcoming issue of 7th Heaven, the Aus7 Modellers Group newsletter. However the signals are in stock at ModelOKits and while the square post GWR signals aren’t exact replicas of NSWR semaphores, they certainly have a McKenzie and Holland “family” look.
Like a lot of modellers I’m a member of a couple of online groups and forums and recently on one of these, a question was posed asking how a Dapol signal could have it’s indication mimicked on a control panel with LEDs. There’s not a lot I normally contribute to this particular group, however I had a Dapol signal in my cupboard that I was planning to evaluate and I had a plan for how I was going to achieve the mimicking on a control panel so I thought I’d take the plunge and put my two cents worth in.
I plan to have my signals switched from a central control panel by a signaler and as such I need this board to be able to display what aspect the signals are showing in locations not in the direct line of sight of the person sitting at the panel. I had a plan for how I was going to achieve this through swapping out the single pole switch provided with Dapol signals for a double pole variety and then switching between red and green LEDs (or possibly a single bi polar LED) on the panel using the extra set of contacts provided by this type of switch. Simple, cheap, effective and, I thought, worth sharing. However I was told in a couple of replies that my suggestion wouldn’t work.
Outside of the possibility that the signals from Dapol in the OO and N are made to actuate in a manner that is different from the way the O-scale ones are, I couldn’t see why what I had proposed wouldn’t work and, in fact, I knew bloody well that it would! 🙂 So today I set out to prove to myself that this could be done, mostly because I plan to eventually populate my layout with about 14 or 15 of these signals and they will all need to have this mimic feature. Before I got too much further down the track I thought I’d better test what I was proposing to do on Morpeth.
I built myself a small box from 12mm plywood to mount the signal to run my test. My roadbed is 12mm ply so this was a suitable material to use. The signal is provided with a plastic nut that tightens a threaded mount on the underside of the signal (the part on the signal that has the yellow line running up it in the photo) which is 15mm in diameter. I drilled a 15mm hole in the ply top of my little box and mounted the signal through this, making sure not to over tighten the nut as it looks like it would easily crack if tightened too far. I plugged in the motor box and the plug leading from the switch provided and tested that the signal worked as advertised. Everything worked beautifully: the red and green aspects were nice and bright and would be very clear under normal layout room lighting. The semaphore worked crisply and even had a slight bounce as per the prototype.
So now I’d tested that the signal worked as produced by Dapol, I made my modifications to test that I could mimic the signal aspect via some “remote” LEDs.
After I’d attached the wires to the new switch I mounted two 5mm LEDs (one red and one green) into the front panel of my little box. I’d used 3mm MDF on the front of the box to allow for the mounting of the switch and the LEDs. I hooked up the power supply that I’d used to power the signal to the LEDs by running the positive to a common connection between the LEDs and the negative to the middle pole of the switch. I ran the two leads from the other poles of the LEDs to each side of the switch inserting a 1k resistor in these lines. I then tested this set up and it worked as I’d hoped it would.
On my first try I got my positives and negatives mixed up running to the LEDs but after swapping the wires I’d soldered to the poles of the switch over the red and green aspects on my 5mm LEDs lit to mimic what was showing on the signal.
After the test proved positive I let out a sigh of relief. I’d had a bit of a vision of how I was going to achieve the mimic feature of the signals on my layout and I also felt that the way I was going to do this would be cheap and simple. I didn’t want to introduce new, extra components to the mix if I didn’t need to. Someone on the forum I referred to earlier had suggested using a flip/flop to achieve the same result. If I knew what I flip flow was this may be possible but as my method works I’ll leave working out what these are for another day 🙂