davepallant Posted February 23, 2016 Share Posted February 23, 2016 Preston and District Model Railway Society have started on a new layout called Euxton which is a 4 track layout based around a junction and station a few miles south of Preston on the West Coast Mainline. It is modern image so we need several 4 aspect colour light signals for the layout. I have already built some N gauge signals for my own layout using 3D printing so thought I would try having them printed at OO scale for the new layout. N gauge In the end I did not do a lot to the files to print them at the larger scale since in N gauge the detail was close to the minimums allowed and it seemed that Shapeways have changed their minimums slightly since bringing in their latest Frosted Extreme Detail printing. I adjusted the thickness of the plate around the signal head and changed the size of the led in signal casing. I left the ladder at twice the thickness of the N gauge model and it looks little heavy but should disappear into the background once on the layout. We needed three different types of signal for the layout; a 4 aspect head on a straight pole, a 4 aspect head on an offset post with the head mounted on a bar offset a few feet towards the track and a 4 aspect head with a left feather for the approach to the junction. The 3D models were built up into a block of 9 signals with a mix of each type so we had spares. I always clean the models with alcohol to get the last of the wax off before a coat of Halford grey primer. I also put a coat of black all over the head inside and out to ensure no bleed through the plastic. The surface mount leds are PLCC-2 size which are quite common and have enough sources to find a good colour green. I got these from Farnell 2322106 LED 1411 Green 525nm2322111 LED 1411 YELLOW 590nm2322107 LED 1411 RED 625nm So far I've only made up the offset head signal. This is the easiest because the back of the head is clear. The straight signal has the railings more in the way of the rear of the head. I used a 1mm fine tip iron and cheap stereo microscope but, unlike the N gauge signals, they could probably be soldered while viewing using a magnifying lens like an desk magnifier with a light in it. Dave Link to post Share on other sites More sharing options...
Benjamin Brady Posted February 23, 2016 Share Posted February 23, 2016 These are excellent, I must say I am rather a fan of the offset one, really caught the look of them. Link to post Share on other sites More sharing options...
Horsetan Posted February 23, 2016 Share Posted February 23, 2016 These are excellent, I must say I am rather a fan of the offset one, really caught the look of them. The 4mm scale versions look less "heavy" than your "N" ones (which were already good enough), so you must be doing something right! I suppose your drawings would translate well into the Dorman LED searchlight-style heads too. Link to post Share on other sites More sharing options...
davepallant Posted February 24, 2016 Author Share Posted February 24, 2016 The 4mm scale versions look less "heavy" than your "N" ones (which were already good enough), so you must be doing something right! I suppose your drawings would translate well into the Dorman LED searchlight-style heads too. The N gauge ones suffer from surface 'jitter' from the printing which then gets thickened up with the paint. They do end up being a little thicker than the drawings look. I'll have to try a Red, Yellow, Green in one of the spare heads. The good thing about the PLCC-2 or PLCC-4 size opening is the availability of multicolour leds. Dave Link to post Share on other sites More sharing options...
Shoey Posted February 25, 2016 Share Posted February 25, 2016 They are absolutely superb! Well done to you Dave. Link to post Share on other sites More sharing options...
Gordon H Posted February 26, 2016 Share Posted February 26, 2016 How will you be dealing with illuminating the feathers? Link to post Share on other sites More sharing options...
class"66" Posted February 29, 2016 Share Posted February 29, 2016 These look realy good Dave.. Link to post Share on other sites More sharing options...
davepallant Posted March 2, 2016 Author Share Posted March 2, 2016 How will you be dealing with illuminating the feathers? Hi Gordon, I've used some 1206 size (3.2mm x 1.6mm) white surface mount leds from Farnell (2062228). The white leds are all in parallel but they seem to be sharing the current fine. There's no room for resistors in there so an alternative might be the five leds in series and a drive circuit that output a high enough voltage to illuminate them. Here it is with and without the green. The leds are a bit bright because I test using a coin battery but it is nice and easy to press the wires onto and it cannot put out an large amount of current if there is a fault. Here is a pic of a signal with the main four leds in place ready to be glued. A four aspect glued and wired And the feather signal glued and wired I did have printed panels to go on the back of the signals but I have ended up just filling to the surface with superglue and then painting the back grey. Dave Link to post Share on other sites More sharing options...
LNERGE Posted March 2, 2016 Share Posted March 2, 2016 Super stuff there. Red to yellow will be driven by the interlocking. What are the plans for the better aspects? Link to post Share on other sites More sharing options...
davepallant Posted March 2, 2016 Author Share Posted March 2, 2016 Super stuff there. Red to yellow will be driven by the interlocking. What are the plans for the better aspects? On our previous layout, Bee Lane, we had IRDot 4 aspect timers which triggered to red as the train went over a sensor and then sequenced back to green with a delay of about 20 seconds per step. This gave the impression of the train running off down the line rather than the reality of it going back to the fiddle yard. In this case we have a junction so we'll either drive the signals with a processor board programmed to have two countdown sequences running - one for each route or we are thinking of going over to driving the signals from JMRI via DCC. We already have DCC points so running both points and signals from JMRI will give us the interlocking and timers we need. Link to post Share on other sites More sharing options...
Gordon H Posted March 5, 2016 Share Posted March 5, 2016 I've used some 1206 size (3.2mm x 1.6mm) white surface mount leds from Farnell (2062228). The white leds are all in parallel but they seem to be sharing the current fine. There's no room for resistors in there so an alternative might be the five leds in series and a drive circuit that output a high enough voltage to illuminate them. When I constructed my Knightwing based demo signal, I used 0603 white LEDs. These are connected in series, main reason being that in future it would simplify construction of a multi-feathered signal by allowing the common bulb to be connected to all branches. As only one is ever illuminated at a time, you only need one resistor too, just a higher supply voltage required. Of course, this principle can easily be expanded for however many feathers you need. The diagram assumes open collector (negative) switching, as is common with DCC decoders (and many other control systems). Link to post Share on other sites More sharing options...
sub39h Posted March 8, 2016 Share Posted March 8, 2016 Excellent work! Link to post Share on other sites More sharing options...
highlandblue Posted November 30, 2016 Share Posted November 30, 2016 Brilliant - have been looking for some realistic signals, and these are just the ticket - have you produced the 4 aspect with feather for purchase as yet? I can't find it on your shapeways shop bud.... Link to post Share on other sites More sharing options...
Suzie Posted December 1, 2016 Share Posted December 1, 2016 Stick with wiring the feather LEDs in parallel if you are considering going DCC and JMRI. Five white LEDs in series needs around 20V at least by the time you have added the current limit resistor and that is not readily available from DCC signal decoders. The Signalist SC1 for example has a separate output to drive the pivot lamp that can be driven at a quarter current compared to the main part of the feather so the brightness matches across the five lamps. Modern LEDs especially when taken from the same batch parallel up very nicely unlike in the olden days. Link to post Share on other sites More sharing options...
davepallant Posted February 9, 2017 Author Share Posted February 9, 2017 Brilliant - have been looking for some realistic signals, and these are just the ticket - have you produced the 4 aspect with feather for purchase as yet? I can't find it on your shapeways shop bud.... Hi Highland, Only just noticed your message - been busy building the layout. I've just checked how I printed the original feather signal. I have only made the left angled feather in one block of 9 different signals so far. That was all of the signals needed for the layout in one go. Also the left angled feather might not be suitable for everyone so I maybe ought to make a series of feathers that can be glued on to the top of the standard signals. That will allow the feathers to be attached to three and four aspect and also to the offset signals as well. It will just need a small hole cut in the top of the main signal to take the two wires up. The glue will be weaker than the original print but only slightly. The question is which ones are the most popular? I can imagine doing left angled and right angled (position 1 and 4) then double feathers (positions 1/2 and 4/5) and maybe the double positions 1/4. That should cover most requirements? Link to post Share on other sites More sharing options...
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