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"Copper Lamp" Project

About

Completed

January, 2001

Current Owner

Steph

Current Location

Sunnyvale, CA

Materials

copper, steel, white LEDs, brass, aluminum, stainless steel

Features

white LED lamp with custom switches made from stock gas-valves, 2 levels of brightness, master on-off switch, somewhat reconfigurable


Summary

The Copper Lamp fits a playful industrial aesthetic. The design goals were for a long-lasting directional LED illumination source suitable for bedtime reading. The components are standard industrial items assembled in a whimsical form. The form evokes thoughts of two eyeballs watching over those below. The limited palette of copper, brass and black enamel are highlighted by the two red handles of the gas-valve switches. (Skip design discussion and jump to pictures at end)

Initial Design with white LEDs

Designs tend to proceed along parallel paths and the copper lamp was no exception. I set out to construct a lamp for lucky-Steph and had several pages of rough sketches. With a rough form in mind, initial limiters to the design were the availability of (reasonably priced) white LEDs. At the time, white LEDs still ran $3 apiece and it was determined that 18 LEDs per head was the limit.

To test the viability and brightness of a white LED design, a PCB was laid out (in Adobe Illustrator, since mainstream PCB programs just don't cut the freeform stuff at all). This PCB was then exposed, developed, etched and bandsawed in my garage. The illumination testing (using 18 precious white LEDs) proved out the ability to read a book with the LED light source several feet distant. No changes were required--I had a lighting design.

To the right, a picture of the LED PCB Illustrator file. You'll note that I considered both SMT and T 1-3/4 packages in the design. White LEDs in SMT packages were still "unobtainium", however.

Switch Design

The switches were going to be a key feature to the design and demanded careful consideration. With the decision to use industrial elements, a ball switch with a red handle caught my eye. The switch was ideal in two ways: 1) it had a 90 degree limiter and 2) it fit the other components I was selecting. The first was important in order to prevent destroying any internal electronics. The second was important, for I had already begun purchasing flexible copper tubing.

But the problem remained....how does one take a gas ball valve and turn it into an electronic switch? I didn't have the answer at first, but I had the tools (Solidworks) to completely model the gas valve and figure something out.

To the right, SolidWorks models of the gas valve assembly and subcomponents. As you can see, I modeled everything (switch, valve components and PCB) and proved out tolerances and assembly method in virtual space.

Switch PCB Layout & Design

Since a rotary switch had already been selected in the solid-modeling phase and the PCB was modeled as well, creating a custom PCB was almost like tracing over a dimensioned drawing. The PCB was, once again, done entirely in Adobe Illustrator and fabricated in my garage.

To the right, is the Illustrator artwork. Also included is the tiled pattern for burning on a pre-sensitized PCB.

Custom Parts

Several of the custom parts are shown to the right. The aluminum parts were designed in Solidworks as part of the switch design. These interfaced the rotary switch to the switch handle and required careful tolerancing.

The brass parts (also shown in the switch design) were actually threaded adapters for the ends of the gas valve as well as adapters for the ball heads. One problem with using industrial plumbing is that not all the adapters are readily available to get from one arbitrary size to the next. To overcome this problem (and avoided having a long adapter chain), I went ahead and designed custom adapters.

Both aluminum switch interface and the brass adapters were machined by a machine shop I have worked with for several years. Since I told the machinist to charge me a fair rate (expensive for small run parts), I'm glad these turned out right and worked the first time!

To the right, are the custom machined parts and the custom PCB with rotary switch mounted.

Pre-Assembly Test

Finding a power supply small enough to fit in a circular junction box was its own challenge! Sure enough, a 24V switcher came to the rescue. It's tight in there!

To the right is a pre-assembly test of the power supply, master switch and LED array. In the background you can see the parts for assembling the gas valve switch.

Copper Heads

The heads of the Copper Lamp are standard ball floats. They were hand cut (lots of fun, believe me) and cleaned up.

To the right is a closeup of one of the heads. In this picture you can see one of the brass adapters put to use, the mounted white LEDs and a few setscrews (to prevent rotation). Although not shown, the LED PCB mounts to the head with a single screw.

Front Body Closeup

Getting a mirror gloss on the junction box really tied things together. As you can see, the entire lamp mounts to the wall with two large brass screws. The power wire comes in through a NPT plug (drilled out, of course) while the master on-off switch is fed through another plug. The front of the lamp is finished with additional brass plugs. Technically, the arrangement of elements can be configured to suit one's needs. In fact, I have design sketches showing this same series of elements as a ceiling lamp, or a multi-head desk lamp.

With the rotary switches (16 position), each gas valve can achieve 3 positions (off, dim, full-on). The switches and assembly have survived years of continual use.

Final Assembly and Mounting

I gloss over some of the assembly details, for they are not that interesting and involve basic wiring issues. The bend on the copper tubing took some iteration.

To the right is a side view of the Copper Lamp. The heads are high enough above the bed to permit sheet changing (a consideration) and far enough from wall to facilitate reading (a requirement).

A straight on view of the Copper Lamp mounted over a bed. The symmetrical design appears perched over the bed with watchful eyes. The black junction-box base carries enough visual weight to prevent the design from appearing drastically unbalanced.

An isometric view of the Copper Lamp.

Switched on, the Copper Lamp becomes beautiful in both form and function.

With the light switched on, the directional illumination is readily apparent. "Stay up reading as late as you want, honey, my side of the bed is dark!"