Experimental: Remote solid state lighting

[djQUAN]

Since I have a need to place lighting in far away places, I usually tap off the renewable energy system at home and run a long length of cable to the place where light is needed.

Running long wires is a pain so I thought, laser might be a possible substitute.

Here's a proof of concept that I intend to implement a test unit at home where there is a dark alleyway on the side and also plan to apply it to a house in the province if it works well enough.

Plan is a 445nm laser installed where there is a nearby power source. The laser is then pointed to a remote phosphor located where the light is needed. The laser and phosphor will be placed high enough so that no accidental eye contact could occur. If the laser gets misaligned, it should point to a concrete wall.

Here is the laser diode from DTR's 3pack. Running it at 500mA gets me 330mW of output through a 3 element lens without too much heat to get rid of. The diode will be mounted inside the diecast box which would act as heatsink and a glass window will be used to protect from the weather.

Remote phosphor mounted about 6m away for testing.

Another view towards the laser diode.

The white light output is comparable to a 3-5W LED. Which I think would be just enough light to walk through a dark alleyway.

The arrangement for the remote phosphor is still in the works and will be figured out once I finish the laser diode and driver module.

 

[Lotus_Darkrose]

This is actually pretty neat. Keep us updated on the progress

 

[Sigurthr]

Nice idea. I've thought of something similar using fiber optic cable to carry the laser light, but if the installation is done right and minor atmospheric signal degradation isn't an issue then open air transmission shouldn't be a problem. Keep in mind the divergence of these multimode beams though.

 

[BShanahan14rulz]

Good thing the target is a large, rectangular piece of plastic. You might could expand the beam out and get a big portion of that plastic to convert. I wonder if efficiency change is noticeable, i.e. does the room look any brighter if you defocus vs. focused as tightly as possible without physical damage

 

[djQUAN]

Thanks guys,

I'm expecting the multimode output and divergence is anticipated so I do intend to slightly defocus it to make it slightly "safer" at distance. I only have 12mm wide strips of remote phosphor so I plan to cut them into short lengths and place them side by side to make a larger, squarish target.

I was planning on using a beam expander to make the beam larger thus lower power density to make it less of an eye hazard but the added complexity and optical loss is not warranted.

I did a bit more work and here is the nearly complete laser source. (Still looking for a suitable window. I don't have a flashlight that I can scavenge the glass lens from at the moment) 12V power is stepped down to 4.6V using a DIY DC-DC converter and two AMC chips limit it at 700mA.

Here's the LPM reading after letting it run for several minutes and getting pretty warm

I tried placing the target higher up to see how much light I can get.

Not bad for 4W total power input. This is what you'd actually see when your eyes get accustomed to the dark.

 

[djQUAN]

This project sat on the drawer since I didn't have time to continue working on it. But we just had a strong typhoon come this morning ( my post this morning ) and wiped out power so everything runs off solar at the moment (led house lighting, phone charging, internet etc).

I didn't install lights in the dining area so this was a chance to test out this remote lighting system I made as a temporary lighting solution when we ate dinner.

I placed the laser on top of a cabinet (nearest place to run a cable since the solar battery is on the second floor of the house)

Another angle

Remote phosphor temporarily mounted on the dining table lantern

With flash, so you can see the ingenious usage of clips.

 

[COMMANDR]

Very cool idea djQUAN. I was toying with using a 405nm to charge some glow powder for a night time light source.
The glow powder would "store" the light and convert it to, in this case, a green light. You could time multiplex the
405nm source to conserve battery power. A work in progress in thought only right now. :>)

 

[djQUAN]

Many have done dinner by candle light but I don't know anyone who had dinner by laser light.

You can run the 405 diode on a low duty cycle just enough to charge the GITD material but if the frequency is too low, you will see "pumping" or "beating" effect of the green glow.

 

[COMMANDR]

Many have done dinner by candle light but I don't know anyone who had dinner by laser light.

You can run the 405 diode on a low duty cycle just enough to charge the GITD material but if the frequency is too low, you will see "pumping" or "beating" effect of the green glow.

I 'm wondering what the efficiency would be on such a setup. I am curious to see if the
GITD material would extend the battery life and also provide useful light.

 

[Sigurthr]

Very nice results!

 

[BShanahan14rulz]

I 'm wondering what the efficiency would be on such a setup. I am curious to see if the
GITD material would extend the battery life and also provide useful light.

World's longest lasting keychain indicator light, this has the makings of!

 

[djQUAN]

Power resumed earlier today but then went out again so we had to eat dinner in the dark.

I wanted to improve the remote phosphor target to improve brightness and reduce the blue light splash and this is what I came up with.

I mounted the remote phosphor using thick wire and superglue. Angled it so that the blue splash will point upwards onto a piece of aluminum so it will reflect back to the remote phosphor. White light that also spills upwards is reflected down by the aluminum.

The laser source on the cabinet

And a couple pics from the top of the cabinet looking down the dining area.

 

[Things]

I think you actually taste your food better if you can't see it. I remember eating by candlelight after cyclone Yasi, could have fed me anything and I wouldn't have seen it