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Post by Deleted on Nov 30, 2016 15:11:28 GMT
Hi Roger....
No limiting resistor, the voltage is low at 3v, the forward voltage of the LED is 3.2v so I'm surprised that it even opens the gate, the amperage is also very low at 20MA so should be ok. I don't really like resistors , heat isn't very friendly to paintwork and for this application not really required. If an LED fails it's cheap enough to replace. Now when it comes to the LED's that I fitted to my car that's a different situation, they not only have resistors but built in fans too. A PCB board would be nice but it would have to be very small to fit and to be honest I didn't want to spend too much time on these, I may require a micro switch of some description though just to keep things tidy. 9.5mm fits, it's the same dia as the 1.5v that I was using before but of course, half the height as I needed two of those to open the LED so more space, I just bought the cheapest that i could find from amazon, they are lithium so should last a very long time. The LED's are warm white and wide angle at 120 degrees.
I'll give all the details of what I've used once finished....on grandfather duties for a few days now but will try to get them done soon.
regards
Pete
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Post by Roger on Nov 30, 2016 15:31:53 GMT
Hi Pete, Thanks for the details. These days, 20mA is a lot for an LED, you can get as much light for less than half that with some types. 3.2V is a surprisingly high Vf for an LED probably about as high as they come. Most are much less, so you would need a limiting resistor for those. You wouldn't get any measurable heat lost through a resistor, and the battery would last a lot longer. Another possibility with a PCB might be to integrate a DC/DC step down converter, I'll have to look into that. It all depends on how little current you can get away with. In my opinion 20mA is miles too much, I'd definitely fit a series resistor to halve that. It's not an easy thing to get right, that's for sure. I'll be very interested to see what the space is that you have available. A drawing of the whole lamp would be great.
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Post by Cro on Nov 30, 2016 15:43:44 GMT
I did look into this when I did my version of the lamp and I was getting very tight for space by the time I had a small switch, LED, resistor and a battery holder on there. If I get looked at mounting the battery a different way it may be a little easier but I had thought of casting in a slot to slide it up into. It's certainly possible but very tight. But yes I agree with Roger 3.2Vf is high but you tend to see that on white LED's over others. But there is no reason why you couldn't half that current and it all still be fine. Best thing would be to fit an RGB and get a warm yellow glow rather than white light as the lamps were a flame (non flickering of course). Roger I feel a side project coming on
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Post by Deleted on Nov 30, 2016 16:16:57 GMT
Thank's Jim... I have seen this site before but don't think that I looked through this particular file.....great pictures...cheers... Pete
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Post by Deleted on Nov 30, 2016 16:23:46 GMT
If I get time tomorrow I'll take some measurements but basically you have a tube, ID is approx 10mm and I guess that it stands just under 15 mm before reaching the neck, these are guesstimates though...
Pete
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uuu
Elder Statesman
your message here...
Posts: 2,816
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Post by uuu on Nov 30, 2016 17:37:54 GMT
Talking LEDs, while we seem to be on the subject. I remember one of the supposed Clive Sinclair innovations in pocket calculators was to only have the display lit 5% of the time, without loss of apparent brightness. Would we be able to switch LEDs like this and the battery would last correspondingly longer?
Wilf
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Post by Roger on Nov 30, 2016 19:35:47 GMT
I did look into this when I did my version of the lamp and I was getting very tight for space by the time I had a small switch, LED, resistor and a battery holder on there. If I get looked at mounting the battery a different way it may be a little easier but I had thought of casting in a slot to slide it up into. It's certainly possible but very tight. But yes I agree with Roger 3.2Vf is high but you tend to see that on white LED's over others. But there is no reason why you couldn't half that current and it all still be fine. Best thing would be to fit an RGB and get a warm yellow glow rather than white light as the lamps were a flame (non flickering of course). Roger I feel a side project coming on Indeed, I get that feeling too, but not just yet eh? Do take a look at this device though, it's the sort of thing I'd probably use..
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pault
Elder Statesman
Posts: 1,497
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Post by pault on Nov 30, 2016 22:19:52 GMT
LED cats eyes in the road flash, you can’t see it when they are in front of you but if you are on the motorway and look out the side window they go past as series of dots.
I did make a lamp some years ago, the battery sat in a pocket in a screw on base to the lamp. To turn the lamp on you screwed the base on a couple of turns, to turn it off you unscrewed it a couple of turns. It worked very well but unfortunately it disappeared. no need for a switch
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mbrown
Elder Statesman
Posts: 1,724
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Post by mbrown on Nov 30, 2016 22:24:49 GMT
If by "disappeared" you mean pilfered, that can be a major problem with small portable fittings. I felt that my lamp was vulnerable so it has an 8BA grub screw to secure it to the lamp bracket. It is completely unobtrusive and it only takes a quick twiddle with a tiny Allen key and the lamp lifts off.
Malcolm
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Post by Deleted on Nov 30, 2016 22:38:05 GMT
LED cats eyes in the road flash, you can’t see it when they are in front of you but if you are on the motorway and look out the side window they go past as series of dots. I did make a lamp some years ago, the battery sat in a pocket in a screw on base to the lamp. To turn the lamp on you screwed the base on a couple of turns, to turn it off you unscrewed it a couple of turns. It worked very well but unfortunately it disappeared. no need for a switch That's exactly the principle that I was working on Paul, I only had to turn the grub screw half a turn to switch on which was a little too small a turn as it didn't always turn off, however with the smaller (in height) battery I'll have more thread to play with, well that's what I was thinking. I also like the idea of just turning the top vent, which is even easier to operate although a little more involved in manufacture... Pete
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Post by Deleted on Dec 8, 2016 17:58:22 GMT
evening chaps....I haven't fallen off the face of the earth..well not just yet...been laid up with a bad cold which has slowed things somewhat....I finally got the new batteries and yes Roger you were correct they were bigger than the LR44's....god knows why i thought then the same size?...anyway I'm putting the lamps on hold for now, I'm happy with all of the components, they work and look right, I just need to look more at holding the batteries and getting the amps to switch off as well as they do on. If anyone wants the list of parts used so far, say so and tomorrow I'll write up a list and post it here. One very small update for today, I have decided to do some more of the parts needed for the smokebox/ saddle and door, I did a little more profiling to the door and it's central spigot, both nearly there now and I'll cover that in a later update but today I spent a couple of hours fabricating the smokebox 'crossbar' I simple thing so no step by step photo's this time just the finished article and a description.... The job starts with two lengths of 1/2 steel at 6" length, the drawing asks for 2.5mm but I only had 3mm which will do. The parts were then held together in the machine vice and 6 3/32 holes were plotted and drilled, then with temporary rivets holding both pieces together the steel was machined as per drawing. Next, I machined 6 x 3/16 spacers, drilled 3/32 first and then parted off at 3/16 length. Final job was to rivet the parts together... Picture of the drawing And one of the crossbar itself... hopefully a bigger update next time.... Pete
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Post by GWR 101 on Dec 8, 2016 19:42:33 GMT
Pete, I would certainly appreciate a list of the parts for the working lamp, but no rush. Regards Paul
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Post by Deleted on Dec 8, 2016 20:18:36 GMT
Pete, I would certainly appreciate a list of the parts for the working lamp, but no rush. Regards Paul will do Paul, i have all of the parts together, won't take me long once back in the workshop to write them all down and post here...as long as my memory holds out that is..... Pete
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Post by silverfox on Dec 8, 2016 21:46:15 GMT
Peter, Xmas pressy ordered today
so words and music much appreciated
Ron
busy working on paperwork at the moment. Anyone else fancy doing 12 US train museums in 17 days next june/july? Hoping to get a visit to see the biggest kit of parts in the world on a non open day. The only answers are no and yes, if you dont ask you wont know!!!!
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Post by Deleted on Dec 9, 2016 17:04:57 GMT
Afternoon guys.. Well, I've been feeling a little guilty about leaving Paul and Ron somewhat in the lurch regarding the working lamps so have spent today finishing one off to show how I tackled this particular job. To start I'll give a list of the components that I've used, all of which are easily available from ebay mostly via 'Bright Components' 1: Bright Components, heat shrink H-01-1.6 2: Bright Components, bulb holder L-B-01-05 3: Bright Components, LED Flat Warm White 120 degree wide angle L-U-02-05 4: M10 plastic grub screws ( actually I went another way, details in description) 5: LR41 1.55v batteries First picture shows the various parts assembled, ideally a 7mm reamer would have been better but I didn't have one so used a sharpened drill bit (be gentle), also seen is a small metal spacer that was used to press the bulb holder with LED into the lamp, it's a tight fit which it needs to be to stop the LED being pushed out. you'll find that the holders push into the original openings nicely without the LED fitted but once they have the LED's you do need to open the opening up a little to approx 7mm to get them to fit. The two white spacers are PTFE (any insulated material will do), the one with the step fit's into the top neck, the other which isn't required if using the plastic grub screw fits between the battery and the securing plate, I'll cover that in other pictures. I have included the M10 grub screw in the picture although didn't actually use it...I've lost the order details but there are plenty of these available from eBay. I modified the LED contacts, the top contact (positive) I shortened and sleeved with the heatshrink, the bottom (negative) contact has a small thin (approx 1.5mm wide) length of brass shim that was drilled one end so that it slide over the LED terminal and soldered in place, the original terminal was then cut off as close to the LED as possible. The shim is over length in the picture, I trimmed it to size after it had been tried in the lamp with the battery, note it's also insulated with heat shrink. This is the bulb holder, cut one of the tabs off, this is to give clearance for the negative lead, note the LED has now had it's negative shim trimmed to length. Next we need to prepare the casting, first, an M10 tap was used to cut a few threads into the bottom, I then ground out a small channel from the lamp opening to the base with a Dremel cutter, this is to give room for the negative lead to fit without being crushed by the battery. The top PTFE spacer had a step turned that was a tight fit into the casting neck , this is to give an insulated contact that the live terminal will be pushed up against as the screw plate in the base is turned to the 'ON' position. Oh I forgot to add that the top live terminal needs trimming so that when the LED is pushed home it's tip is around the middle of the casting, it's not critical but you must be sure to not let it touch the casting itself. This picture shows the battery being tried for fit, this pack consists of two LR41 batteries held together with some heatshrink , I seemed to have lost the details but it was basically heatshrinkj that was around 9mm in it's unshrunk state. You can just see the PTFE spacer, this needs to be at a height that's just below the lamp opening. Once happy with the battery fit it's time to insert the LED, as mentioned this first entails increasing the opening to around 7mm so that the holder is a tight fit, you also need to ground down the LED face itself (unless you can find smaller depth LED's than I that is) . I did this simply using some Wet & dry on a flat surface, it takes a little time but easy enough, I ground off the front face until it was very close to the LED internals, once polished it's nice and clear again, don't be tempted to use too coarse a paper or you may not be able to polish out all of the marks, I finished with 1500 grit and plenty of water. Now some may be tempted to use normal rounded lens LED's and do away with the lamp lens that comes in the kit altogether, I resisted this as it will place the light source out of the lamp which for me would look totally wrong, I do accept though that this would make life somewhat easier. I used the small spacer that just fits into the opening to push the holder home in a vice. here we have both the LED and battery fitted with the negative shim tab folded under the battery just awaiting the screw plate to be fitted, in this picture it shows a cut down plastic grub screw but this was a little problematic do to only having a few threads to screw into an thus changed to a slice of 10mm studding that I cut a line across it's face for using a screwdriver to fit. And so here's the metal plate fitted in it's off position, it's litterally just one thread and thus not sitting square although this straightens out once turned on, the important this is it's in and won't fall out. so...what's it look like, here we see the lamp while switched off, now John of JCT fittings states not to use cyan (super glue) to hold the lens in place, rightly so as it can craze the lens due the glue turning white, however, we have moved on a little and the rubber type superglue works nicely, just use the smallest amount possible in a couple of spots to hold the lens in place. You don't want too much as 1, it could smear the lens and 2, one day you may need to change the LED. Finally, we have the money shot, a working LNER lamp, i'm quite pleased with the end result, i hope you guys like it too.. next week, back to the smokebox and it's door, lot's of work to do there, i'm looking forward to adding 4472's much loved face... regards Pete
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Post by silverfox on Dec 9, 2016 19:29:16 GMT
Peter
Thanks
Due to a wife who still believes in Father Xmas, will have to commence work after Dec 25!. BUT i can at least stock up with the bits.
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jma1009
Elder Statesman
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Post by jma1009 on Dec 9, 2016 22:54:23 GMT
Hi Pete,
Sorry to hear about your cold - hope you are feeling better.
Wow - that working lamp is quite something!
Quite a few of us have used John Tipton lamps, and I am sure your working lamp would be of great interest to many - perhaps an article for ME? Perhaps John might put together a kit for conversion too? Licence/copyright the design!
Cheers, Julian
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Post by Deleted on Dec 9, 2016 23:16:33 GMT
Hi Julian... thank's for the well wishes and comment on my lamp.. I'm surprised that John doesn't do a lighting kit, it's not complicated but is a little on the fiddly side, perhaps due mainly to my big fingers.... Pete
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Post by silverfox on Dec 9, 2016 23:56:40 GMT
Peter
having probs locating the items ( bulbs and bulb holders) on the Bright site. When i put in the ref L-U-02-05 i get 'nothing found' reply! Am i doing this right? ( i know its late)
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Post by Deleted on Dec 10, 2016 0:05:10 GMT
hi ron I had a quick look, seems they have changed the design or perhaps currently just have another type available..... I found these, they look very slightly different but are of the same 5mm size and work in the same way, ie clip in , I see no reason why these wouldn't do the same job. i would advise though to check what size you need to open the hole at as it may be slightly different. what i did was to insert an LED into the holder and then measure the diameter as it grows with the LED in. You need the hole a little smaller than this, i suspect that they will be the same size but best to check... here's the link www.ebay.co.uk/itm/20x-5mm-LED-Bezel-Clip-Holder-Mount-Push-Fit-1st-CLASS-POST-/301368922730?hash=item462afcd26aregards pete
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