Light Globes

lightedI created light globes in HO for some friends – Bill Gill and Greg Shinnie and had them printed at Shapeways. Greg then – using his magical powers lit one with Nano LEDs from Ngineering. The results are shown on the left. The SBS was published on Railroad Line Forums –

These came out great – Greg gives a complete SBS on the process at this thread .. HO scale school light globes

I started to look around for a possible alternative to the Ngineering LEDs .. specifically on eBay. If found some very small LEDs .. and they came pre-wired. I thought I would give them a try.

Pre Wired SMD LEDs from eBay
There were several sizes LEDs available from one source on eBay which quickly got me to thinking .. make light globes fit the LED. Since they provide everything including dimensions this makes it easy(er) to get down to designing a globe to fit them.
Image1I purchased 20ea of the #1206 from eBay – Pre-wired SMD (Surface Mount Device) LED White. I liked the idea that they were pre-wired and to top it off they came with resistors. Total cost with shipping was $14.49 which means that each LED/resistor cost me 73¢. It did take quite a while to get here, just over a month – but the page did give a 15-20 day delivery time for shipping to the United States with the addendum that *Delivery time might be longer if the item(s) be inspected by customs*

From the diagram we can see that the LED is 1.6mm/0.063″ wide and 3.2mm/0.126″ tall. The thickness of .8mm/0.032″ has the wire thickness of approximately 0.28mm/0.011″ added to it for an overall thickness of 1.08mm/.043″.

This gives plenty of information for the constraints in designing the globe.

section_1I used the scaling tool in Sketchup to ‘push and pull’ on the globe shape until I could fit the 1206 within the body of the globe.

This includes the ‘cap’ that fits over the neck of the globe. I figure this could be used .. or not .. up to the user. Note that I said the two wires are 0.028mm dia each. Doubling them together gives 0.056mm or about 0.022″. I kicked that up a bit to 0.030″ dia hole in the cap.

The chart shows varying measurements for everything from 1:160 to 1:24. Just how useful the globes would be for any scale is ultimately up to the end user .. so there you go ..

Example – for O scale, the globe dia (8.63″) and height over the cap (8.86″) is perfect for smaller globe lights. Not so much for the other scales perhaps .. but .. again that is up to each individual to decide.

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