Giant Vacuum Tube Smart Lamp

Do you remember peeking into old electronics and seeing the glowing vacuum tubes? I have good memories of the radio that my grandma owned and I wanted to recreate the cozy feeling.

For those who don't know these components were used before transistors. They are typically 5 cm or 2" in size. My goal with the design was to strike a balance between being true to life, functional and not too complex to build. On the technical figure you can see all the parts of a vacuum tube of which I chose the following to include in my model:

• The heated filament which is the component that glows at the center of the tube
• Around the filament, you can find the gird which looks like a coil wrapped around two rods. Some vacuum tubes can have 3 or grids and some don't have any, I chose to include 1.
• The cage consists of a wire mesh forming a cylinder with a spacer on both the top and bottom. This wraps around the grid.
• On top of the cage there's a rectangular metal part called the getter.
• 6 pins will be included in the design and those will also be used as support rods.
• And of course, the glass envelope that covers everything. The top of it is covered by a silvery shine which is characteristic of vacuum tubes.

The pins that stick out from the bottom of the tube are normally not seen as the tube is sitting in a socket. Another reason why I didn't want them to stick out is that I planned to keep this lamp on my nightstand and with a flat base it's harder to accidentally knock it down.

In the first place I wanted to use materials I already had laying around at home that's why you see things like jar lid or coathanger. There are many ways you can create a similar lamp so feel free to use similar materials you have.

Materials:

• 12 cm x 26 cm (5" x 11") piece of galvanized wire mesh, with 6.25 mm (1/4") gap between the wires
• spring from a ballpoint pen
• 6 pcs 16 cm (6.3") hollow metal rods
• preferably with closed ends, mine were 7.6 mm (0.3") diameter stainless steel
• 10 cm x 6 cm (4" x 2.4") size, thin aluminum or steel metal sheet
• 2pcs 8.3 cm (3 1/4") in diameter stainless steel jar lid
• 11 cm (4.33") long, 2 mm thick steel wire
• 12 cm (4.7") diameter, 21 cm (8.3") tall glass dome
• 2pcs wooden bowl
• 13 cm (5") outer diameter
• 10.5 cm (4") outer diameter
• silver spray paint
• masking tape
• plastic bag
• used for masking
• nano gel tape (also sold as Alien Tape)
• 0.8 mm (1/32") soldering wire, around 1.5 m (60") in length
• it is used not only for soldering but as building material
• epoxy glue (optional)

Electronics:

• 12V power supply
• 5.5x2.1 mm DC plug (or the size that matches your power supply)
• 13 cm (5 1/8") long LED filament (2200K or warmer)
• 100 Ohm resistor
• ZigBee LED strip controller (optional)
• electrical wire, I used about 50 cm (20") in total
• 20 cm (8") long, 2.4 mm (0.1") diameter shrink tube

Tools:

• safety gloves
• safety goggles
• dust mask
• Dremel multi-tool with a cutting wheel and sanding drum
• Hand drill with a step drill bit and regular drill bits
• a pair of pliers
• aviation snip (optional)
• soldering iron
• small wood saw (or jigsaw table)
• 60, 150, and 320 grit sandpaper

.

It's a good idea to start with the cage first as the components you make here will influence the rest of the build. I created a template that you can print out in both A4 and letter formats.

The jar lids were into the spacers. There are 6 pins that also act as support rods that hold the cage. 4 of the support rods go through the spacers and holes should be drilled for them on the spacers. My rods are not standard diameter so I used the step drill bit to slowly widen the holes to the desired size. The 5th hole in the center is for the filament to pass through.

The next step is to make the lids look more like the spacers. Mine were too tall so I cut them down to 2.5 mm (0.1") in height and also included 6 evenly spaced "teeth" as the ones on the JBC 1C4 vacuum tube. Afterward, the sanding drum can be used to clean the edges.

The next component is the wire mesh that you can also find in the template. With a marker, I marked the places where they need to be cut and used a pair of pliers to cut out the shape.

Tip: If you can't find a jar lid that's the size you want you can also just cut a circle from a metal sheet. It's just easier to get a perfect circle when starting from a lid.

The base consists of two wooden bowls. The smaller one is placed upside down inside the larger one and the space between them is used to house the LED driver. I for the larger bowl searched for a bowl that can fit the glass dome inside and picked the one with the closest match. It's not quite right from the start so I used sandpaper from 60 to 320 grit to widen it. The DC jack is also placed on the side of the larger bowl. I first drilled an 8 mm hole so the plug can fit through. Then I drilled with a 15 mm drill but only halfway through which is needed so the plug can be screwed in from the back.

The smaller bowl was also a bit too high which I solved by cutting a thin slice from the bottom using a saw. Next, I drilled the 6 holes for the support rods. The placement of these are also included in the template from the previous step.

The hollow rods were cut to the following lengths using the cutting wheel in the Dremel tool:

• 2pcs 16 cm
• 2pcs 14 cm
• 2pcs 2.5 cm

2 mm holes were drilled in the shortest and longest pairs of rods as they are both bridged by a 5.5 cm long, 2 mm thick solid steel wire where the filament can be suspended. A small groove was also cut into these wires so the filament stays in place.

The 14 cm rods are the ones around which the soldering wire was wrapped to create the grid. I chose soldering wire as a material because it holds its shape fairly well and doesn't want to spring back while also being thicker which is good for aesthetics. 9 turns are added (later in the assembly step) and small grooves were added to the rod using the cutting wheel so the wire stays in place.

The spring for holding the filament was created by cutting a spring from a ballpoint pen shorter and bending the wire in the end at 90°.

The glass envelope is created by taking the glass dome and painting the top part silver using spray paint. The easiest way is to paint it from the outside, but in real vacuum tubes the shine is created by ions on the inside which get deposited on the glass. That's why I decided to paint it from the inside which has the added benefit of being more durable as it won't be scratched when cleaned.

I put the masking in a circle on the inside then secured the plastic around the whole glass also using masking tape. I applied 3 layers of paint with 30 minutes between them then let it cure for an hour before carefully removing the masking tape.

I have smart bulbs around the house that use the Philips Hue smart home bridge. These are ZigBee devices, that's why I chose a ZigBee LED driver. It is also compatible with smart home systems for example Tuya Smart.

I created schematics that you can follow on soldering the components together. If you are not using an LED driver just connect the LEDs, resistor and directly to the DC jack. I removed the PCB of the driver from the housing and desoldered the cable, but left the onboard DC jack in place as it would have been more difficult to remove without damaging the rest of the board.

Bend the end of the LED filaments at 90°, solder them together, and slid a small piece of shrink tube for insulation. Fold a loop on the wires that connect to the end of the LEDs and solder it that way as well. The spring that tensions the filament will be threaded into these loops later.

The getter is cut out from a thin metal sheet using an aviation snipper, but if you don't have one the Dremel tool with a cutting wheel works as well. The template for this is also included in the pdf.

Tip: Drill the holes first as that way you have a bigger piece of metal to hold onto while drilling. Cut the outline afterward.

Now comes the fun part: assembly. Start by sliding the two spacers on the 14 cm rods and push them into the base. This will keep the rods in place so you can wind the 9 turns of soldering wire around them thereby creating the grid. After that, you can add the two 16 cm rods and the wire mesh to form the cage. Then add the two smallest rods to the base too. After placing the getter on top of the cage, connect the two shortest and two longest rods using the 2 mm thick wires. Thread the LED filament through the middle of the cage then suspend and tension it between the bridging wires with the small spring you made. The tension should be light, just a little help to keep the filament straight. You can adjust it by pulling apart the two ends of the spring using pliers which helps to loosen it. Thread the wires of the filament through the holes on the shortest rods and twist them together with the wires from the LED driver. The final step is to put the glass in place.

Everything fit together really snugly so I didn't use any glue, but feel free to use some epoxy glue if you feel like the parts are moving. I only used nano gel tape to keep the base together and the wire in place.

And you're done! If you used a ZigBee LED driver then plug in the lamp and search for lights in your smart home app, it can be added like a normal light bulb. Thank you very much for reading, I hope you enjoyed it! :)