I initially posted this over in the General forum but didn’t get much of a response, so I’m going to try here now…
I’ve been recently mulling over lighting my layout sparsely with both interior and exterior lights, using grain of rice/wheat bulbs. What’s the best way to control the brightness of the lights? And, how should I go about controlling them individually?
Someone suggested to me using a voltage regulator as an overall control but warned if the VR ever “bought the farm” it would take all the lights with it. [:(]
How would I go about wiring up an array of lights to control them independently? Is there a good resource, book, or website that I can use as reference for someone with limited electrical knowledge?
Sorry if you’ve read this already. Thanks for your help! [:)]
If by “control the brightness” you mean adjust the brightness at different times to different levels, then a variable voltage regulator (LM317) is about the only way to go. It’s only good for about 1 amp so if you have lots of lights you’d have more than one and they all wouldn’t all go out at once if it failed. It’s short-circuit proof so if you keep your load under 1 amp you should be okay.
If you just want to set the level of the lights to something lower than full brilliance, try a 10 volt transformer instead of 12 volts, or 12 instead of 16 volts depending on the lamp’s requirements. You could put a resistor in series with each bulb but it can get a bit messy calculating the ohms and watts for the resistor and they get warm. Another way is to put a rectifier diode (1N4001) in series with the bulb. A diode loses 0.7 volts and there’s no calculations involved. Two diodes in series would lose 1.4 volts. If you’re using D.C. for your lights, install the diode in the positive wire with its white band towards the lamp.
I have some rough ideas on ways to have building and streetlighting controlled by decoders run from a fast clock bus, but haven’t worked out all the logic yet. I plan to do this using the tiny LEDs listed on that site.
I’m not clear exactly what you are trying to accomplish. If you are thinking of actually varying the brightness of individual lamps at will, I can guarantee you that there are much better goals in terms of your time and resources. In any event, if you are talking (as I assume) about 1.5 volt bulbs, you should build or buy a 1.5v power supply; it’ll be a whole lot simpler than wiring resistors in, etc. One piece of practical advice: you will save yourself a lot of trouble and complication if you standardize on a single bulb type from a single supplier - and even buy them at the same time.
It also depends on the era which your modeling. If you modeling from the 60s or before the street lights were no as bright as they are now days so you would want the to look dimmer. The longer run (more) you have, you will see lights getting dimmer as your power (AC) will be getting lower voltage also.
I have wounder about the bightness and what not of my lighting of buildings also, i went the cheep way and bought a set of clear christmas lights from the store and cut and spliced them together and ran them under the table into my buildings. So this year im buy a set of christmas lights that have the control on them to make them flash/blink/brightness and seeing how that works out ~ChriSS