If I had an iPhone 5 or 5s, I'd seriously consider this to check for hot spots in a lamp I converted from halogen to LED. Bad connections can generate heat. I'm a novice when it comes to electrical construction, and so it would be nice to have some confirmation that I didn't botch any connections. I've used a non-contact IR thermometer to check for hot spots and have found none other than were expected (the heat sinks of the LED bulbs), but this method doesn't have very good resolution.

In case anyone has an old halogen torchiere lamp sitting around and would be interested in such a conversion, here are some photos of mine to give some ideas: http://imgur.com/a/XbtNc#0

The first photo shows the mount I constructed to hold the bulbs. The parts are four 2.5" corner braces, four 4" mending plates, four Leviton 3352-F lamp holders, and several machine screws, nuts, and lock washers. (There are no lock washers in that photo, because that was a test to check fit, not the final assembly). All the parts for the mount, except the lamp holders, are at the big stores like Home Depot or Lowes for a total of under $10. The lamp holders were at Do it Best Hardware for around $10 for four of them. [1]

I did not have to drill any holes to make this work. Everything is using the holes that are built into the corner braces and mending plates. In particular, the distance between the diagonal holes on the bottom turns out to differ by only about 1 mm from the distance between the holes on the lamp bowl that were used to attach the original halogen socket. That's enough overlap for a #6 machine screw to easily go through and securely attach the thing.

The second photo shows the 4 switches I added to the lamp bowl to control the lights. There are two "on-off" switches, and two "on-off-on" switches. Each lamp holder is controlled by one of the switches. The two on the "on-off" switches can simply be turned on and off with their switch. The two on the "on-off-on" switches are wired so one way turns them directly on, and the other way connects them to the dimmer that is in the lamp pole. Yes, I am aware that I am morally obligated to paint this to look like the underside of a cow.

My original plan was to have two 1600 lumen 2700k bulbs, and two 1600 lumen 5000k bulbs. This would give me a lot of flexibility. If I wanted 2700k light, I could switch one bulb to the dimmer to get from low to 1600, and I could turn the other bulb on to go from 1600 to 3200. Same if I want 5000k light. And if I want even more light, I could do both of these at the same time. [2]

The third photo shows it with everything wired up. It is not pretty, as I pretty much just went point to point, but did not do a very good job of picking segment lengths. And yes, I realize I should insulate the backs of the switches. I'll be using electrical tape to cover those exposed terminals. They are not covered yet because I'm still in the testing phase. I also might rewire it to make the wiring cleaner. (I'm also considering putting the switches in a plastic box)

The gray and orange 3 way connectors are Wago Lever-Nut connectors. They are awesome. They can take any mix of 12-28 gauge wire, they connect by simply lifting the lever, inserting the wire, and then lowering the lever. They disconnect by reversing that, and the wire comes back out completely undamaged, and the connector is completely reusable. Rated for 600 volts, 20 amps. I used these for the connections that connect the stuff in the bowl to the wires coming out of the pole so that the bowl can fairly easily be removed from the pole. Their only downside is that they are more expensive than other connectors, like wire nuts. A box of 50 from Amazon worked out to $0.40 per connector.

The yellow connectors are In-Sure push in connectors. It is possible to remove them, but they are not re-usable, so are really meant for permanent connections. A jar of 200 from Amazon was $0.13 per connector [3].

Not shown is the shade. This design places the bulbs above the rim of the bowl, and this leads to harsh shadows in the room. Right now, I have a simple shade I made by taking some white construction paper and making a cylinder of just under the diameter of the bowl. This sits on top and diffuses the light, although it also absorbs quit a bit. I think I want something that only blocks the front quarter. Currently trying to decide mechanically how to make that work...looking at making some kind of frame out of wire to hold the paper (or some more translucent material) in place. I'm also trying to figure out if I can make some kind of adjustable shade that would let me vary the amount of light blocked, which could serve as an alternative to electronic dimming.

[1] The most surprising thing I learned during this project was that buying these parts from my local big chain hardware stores in person was about 1/2 the price I could get them from Amazon.

[2] Another approach I've toyed with is three 1600 lumen bulbs and one 800 lumen bulb. For very low to 800 lumen, I'd use the 800 lumen bulb on the dimmer. For 800 to 1600, I'd use one of the 1600 lumen bulbs on the dimmer. Add in the other two 1600s to bring the range up to 5500. I've also considered getting rid of the dimmer, and going with 450 lumen, 800 lumen, 1600 lumen, 1600 lumen.

LED bulbs do not dim all the way to zero. Their range is something like 20-100% (my estimate from eyeballing it). That's why I did not go with the simplest conversion, which would be four 1600 lumen bulbs all on the dimmer and no separate switches. The dimmest non-zero output would then be something like the equivalent of a 75 watt incandescent.

[3] I should have checked Home Depot. They stock them locally, in 100 packs, for $0.07 per connector.