Introduction: Eclipse Lamp
The Eclipse Lamp is a simple, wooden circle that hangs on a wall and fades up to a soft glow when you turn it.
Light glows through a thin layer of wood veneer of the front of the disc, and semicircular holes in the back create a halo-like glow on the wall behind it.
Using an LED strip, laser-cut plywood, a sheet of wood veneer, and some off-the-shelf hardware and electronic components, I was able to make this lamp in about 12 hours. I can't be sure, but it might be the world's biggest knob.
Step 1: Design
I was inspired by the Halo Lamp by KJARTAN OSKARSSON STUDIO. They designed a gorgeous wooden ring that hangs by a sort of pulley- When you tug on a leather strap, their donut shaped light both rotates and dims the light at the same time.
I love the idea of a direct, manual interaction with a light source, so I decided to make my own take on this concept.
Having just made a veneer covered lamp for my Hidden Silhouette Lamp instructable, I wanted to use the same technique to make a big wooden disc that hangs on the wall and becomes a lamp when you turn it.
Like pretty much everything else I make, I designed it in Fusion 360 . It's free, it's stable and versatile, plays nice with STEP models from McMaster Carr, and it's free indefinitely unless you make more than $100K a year on the stuff you produce with it. If you want to learn to 3D model the kind of work I do, I think this is the best choice on the market. Click the links below to sign up:
VERSION 1: BAD DESIGN
Version 1 of this design used a 1/2" shaft with a steel bearing and shaft collars to support the disc and allow for linear motion. It seemed fine in theory, but as you'll see later in the instructable, it put too much stress on a precarious press-fit part. If the body of the lamp had been made of metal it probably would have been fine, but press-fitting a metal bearing to support all the weight of the piece made for a wobbly rotary action.
VERSION 2: BETTER DESIGN
With Version 2, I changed to a lazy-susan style 12" bearing so there would be much more contact between the fixed back part and the moving front part. With this setup I was able to have smooth motion with a very strong and stable connection.
The f3D file is a copy of the 3D file I used to design the piece. The DWG file is a layout of all the parts to be cut. Notice the layers are separated into "Cut" (that's for the 1/4" plywood), "Eighth" is for the 1/8" plywood plate that holds the potentiometer.
There are two different iterations in this instructable, the DWG files represent the second, better design.
Step 2: Tools & Materials
At first, I was planning on using a rotary encoder with an arduino, but I decided to go with a much simpler, off-the shelf design by deconstructing a 12V LED dimmer. Here are the parts I used:
- 12V LED Strip
- PWM Dimming Controller
- 12V AC/DC Power Supply
- Wire, Solder, Heat Shrink Tubing... basic home electronics stuff.
- 6-32 Machine Screws: 12
- 6-32 Steel Standoff: 6
- Ring Style Turntable (NOTE: This turntable may not fit the hole pattern in the cut files. The one I used was found in the shop. To make it fit, change the hole pattern to match.)
- 4-40 Machine Screws: 4
- 120W Epilog Laser Cutter (any laser will do, or this can be done by hand with a jigsaw / drill / bandsaw using the technique described in my Digital Fabrication by Hand instructable)
- Wood glue, hot glue
- Soldering iron
- 1/4" Plywood
- Maple Veneer
Step 3: Plywood Assembly
The plywood pieces interlock and stack to make up the parts of the lamp. I decided to go with glue joints almost everywhere in order to make a more solid piece than I might otherwise achieve with bolted connections.
The plywood pieces are split and arranged so that they take up less space on a sheet. Making a 24” ring that’s 1” thick is a huge waste of material. I split the rings and large back panel into 3 pieces each (cuts at 120º angles).
I added 1/4” holes through the whole stack in order to make accurate assembly fast and easy- you simply stack the pieces with glue in the seams and surfaces, then hammer a joining dowel through each hole. The two 1” rings stack to create a ~1/2” wall around the inside of the large panel. After gluing and adding the dowels, I clamped down the parts to make sure I wasn’t getting any bubbles or uneven surfaces.
Step 4: LED ASSEMBLY
First, I epoxy’d the LED strip around the inside of the 1/2” rim. 5-minute epoxy works well- you can’t rely on the adhesive backing these things come with, they’re practically useless. When you reach the end of your piece, you simply cut the strip with scissors.
With the LEDs in place, I peeled back the plastic coating on the end of the strip to expose the soldering contacts, then soldered on black and red solid wires that I would later connect to the dimmer. It’s always important to ensure a structural connection for wiring- never rely on the solder contacts to keep wired connections in place, this will inevitably cause shorting. To prevent this, I just hot-glued the wires down to the back panel, leaving enough slack on the ends to redo connections if needed.
The dimmer box has screw-down contacts on it which are very handy for testing. Before assembling the rest of the electronics, I tested them by connecting the dimmer- it worked! Honestly it’s pretty hard to get this wrong, there are only 4 connections (+- power in, +-power out). Testing in this case is really just checking for bad solder connections.
Once the LED strip was epoxy'd in place, It was time to add the veneer to the front of the disc. Veneer this size (as far as I know) only comes with a paper backing. If it didn't, it would just split along the seams, and it also keeps glue from seeping through the thin layer of wood. Needing as much translucence as possible, I sanded off the back layer of paper to get the the wood.
I left a rim of paper about 1" wide to allow a better adhesion to the plywood rim, then wood glued and clamped the large turning disc to the veneer.
Step 5: BEARING & GEAR ASSEMBLY (BAD DESIGN)
First, I measured the shaft in my model and cut my shaft to length.
The bearing press-fits into the plywood hole in the large disc. This feature creates the main problem with this version of the design- plywood is neither solid enough nor precise enough to make a good press-fitting with a precision steel bearing.
Next, I added the 1/8” plywood plate with the disassembled potentiometer attached to it. In order to get the gear contacts in the right place, the plate has to be on the outside (front) of the wall-mounted disc. This plate screws in with 4-40 screws through sized holes in the 1/4” plywood piece.
With the bearing and shaft fit, I added the outer collar (the one the holds the wall-mounted disc off of the large, turning disc), then the outer panel of the wall-mount disc, then the inner collar. The collars attach with a screwed clamping action.
Having the offsets worked out carefully in the computer, the gears contacted perfectly without any unwanted pressure on the potentiometer.
A note on gears: I designed the spur gear that press-fits to the potentiometer with 24 teeth. The rack I designed to fix to the large, turning disc has 192 teeth (or it would if it was a complete gear). This means that 1/8 of a complete turn on the large disc will turn the potentiometer gear a full rotation.
The reason this was a bad design however, is that the press-fit plywood connection didn’t create a solid, parallel connection. The large, turning disc wobbled when moved. Back to the drawing board!
Step 6: BEARING & GEAR ASSEMBLY (GOOD DESIGN)
We had a ring style turntable lying around the shop, so I measured it and used it for the redesign. I figured having a much larger bearing with screw-hole connections would make for a much stable turning action.
I didn’t like the 1/8 disc turn = 1 full potentiometer turn action that I got with the 1-8 gear ratio I designed previously. Making a smaller gear ratio of 1-4 would make the dimming action smoother and would have a better feel overall- like turning a giant knob, which is kind of the point.
The other problem with keeping the same gear action is that the potentiometer would be in the way of the turntable, so it had to be moved anyway.
I designed the new parts to just attach to the parts I had already assembled, the new parts are as follows.
- I made the new gear with a 1/4" hole in its center and a circle with a 1/4" hole in its center and joined them using glue, clamps, and a 1/4 dowel to keep them aligned while the glue cured. When the glue cured, I removed the dowel so that I could feed the wires through to the electronics on the back plate.
- I made 3 tabs with machine screw holes that can be glued individually to the back panel of the turning disc. These tabs have semicircular ends that but against the center circular piece of the turning disc, which ensures that the turning disc and mounting disc are aligned at their centers. I was able to find the proper angles by aligning the mounting holes in the turntable with each tab. Some extra 6-32 flat-head machine screws attach the turntable to the turning disc.
- The front plate of the mounting disc has 3 semicircular cutouts in it. This allowed me to screw the turntable to the mounting plate, then screw the other ring of the turntable to the turning disc through these cutouts.
With the 1/8" potentiometer plate attached to the front panel of the mounting disc, I fed the LED wires through a drilled hole (that I forgot to add in the Fusion file), and wired up the electronics. Everything is labeled on the dimmer switch, so you really can't mess this part up. There's a mounting tab for the female end of the ACDC adaptor connection as well, which allows you to easily plug and unplug the power source.
Step 7: FINISHING TOUCHES
The last thing to do was to finish the turning disc and spruce up the power adaptor.
The turning disc’s outer edge was still laser-burnt wood, so I glued a strip of veneer onto it so that the disc would look like a solid piece of wood. I did this with wood glue and a ratchet strap- it worked like a charm! I left a little extra material around the outside of the disc that I trimmed off with a razor knife when the glue had dried.
For the power supply, I removed the ugly black plastic wire and replaced it with some fabric lamp wire. I also added a little laser-cut box with matching wood veneer on all the panels. Having all the parts made of similar or harmonious materials makes for a much better design.
Step 8: FINISHED PRODUCT
I really like the look and feel of this piece for the most part. There are a few things I'd like to change in the next round.
- The hot spots around the edge are a little distracting. Adding a second rim that's 2" thick to cover the edge of the LEDs will probably resolve this issue.
- The diffusion isn't great- it's dim in the middle and bright around the edge. I was thinking of adding a diffusing acrylic panel against the veneer to help with this.
- The veneer is a bit wavy in the middle- it's hard to keep such a thin layer of wood from warping. I think in round 2, I'm going to glue the veneer to the diffusing acrylic to make for a smooth piece.
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