The Elroy Lamp: A transparent LCD table lamp

Elroy is a table lamp with a unique feature — the shade can dynamically change, at the swipe of a finger, to a new style or pattern to complement your mood, the time of day, or an event, all from your phone or web browser.

Elroy is a concept and personal DIY project. I’ll share some learnings and details on how I built it. These aren’t step-by-step instructions, but I hope they’ll be helpful to anyone that’s inspired to build their own design.

Overview

Elroy is essentially a computer with a 4-way display, backlit by a bright LED bulb. The four sides of the lamp shade are made from translucent LCD displays, and acrylic and paper diffusion layers. The light source is a very bright 35W LED bulb. The displays are driven by a single board computer running Linux and custom software to display and manage images. The lamp is controllable over wifi via a simple web app.

Translucent LCDs

I salvaged some 13” LCD displays from old laptops and found additional matching displays on ebay. I disassembled each display, removing the frame, backing layer, diffusion film, and backlight. This took some practice to get right. The LCD glass is quite fragile. I broke 2 panels during disassembly and had to find replacements. The trick is to remove the electrical tape that holds the display together without flexing the LCD glass so much that it cracks.

What’s inside? From top: 1) A shiny white paper layer to reflect the back light 2) a transparent polycarbonate sheet with a film to scatter the back light 3) a stack of different diffusion films 4) metal frame 5) the LCD glass panel with circuit board.
The backlight is a row of super bright LEDs tucked into a channel in the metal frame. Some other LCD panels use a cold florescent tube instead of LEDs.

The remaining LCD panel is translucent: LCD displays are a sandwich of transparent glass embedded with liquid crystals and tiny transistors, surrounded by layers of polarizing film. In the photo below, I wrote a message on a piece of letter paper, placed it on a clear piece of acrylic, on top of a bright backlight. You can see the LCD display on the right is translucent, but similar to a pair of sunglasses, the polarizing film only permits a fraction of the backlight to emit through the panel.

A message on paper.
Looking through the LCD panel.

Polarizing film is necessary for the function of an LCD display.

Lamp Light & Diffusion

Given the low amount of light emitted through the display, to create a sufficiently bright lamp, a very bright light source is needed. Also, though an LCD display is typically backlit by a light with a cold color temperature (around 5000K), lamp light is typically a warm color temperature (like 2700K). So the ideal bulb must be bright and warm.

A 4-bulb array I experimented with.
The gigantic 9″ long 35W LED bulb I chose beside an ordinary LED lamp bulb.

I experimented with multi-bulb arrays, and different bulb options, but settled on this 35W (300W equiv) LED bulb. This bulb is giant and takes up quite a bit of space within the shade. It’s bright enough that it shouldn’t be directly exposed — it would be uncomfortable (maybe dangerous?) to look at directly.

Next, without some work, the light from the bulb, when viewed through the LCD panels, would be a harsh point-light concentrated in the center. I wanted to diffuse the light evenly across the surface and produce a textured, fabric-like aesthetic. I experimented with different acrylic and polycarbonate sheets and paper materials.

Diffusion through mulberry paper.

Here’s one experiment result I really liked, but didn’t end up using. This is mulberry paper, which has a unique texture that’s simultaneously woody and linen-like, has nice diffusion properties, and transmits a lot of light. This looked great with black and white patterns and particularly complemented a Japanese lantern aesthetic. I felt like the large and non-uniform fibers didn’t work as well with a diverse set of patterns.

I found the best combination was this sandwich (starting from the inside):

  • Frosted acrylic 1/8″ 90% emission (film facing out)
  • Vellum tracing paper
  • LCD
  • Rice paper
  • Clear anti-glare polycarbonate 3/32”
Close up of lamp where texture is visible.

The acrylic and polycarbonate sheets also add some structure to protect the LCD glass from flexing and breaking. I wrapped the edges of each sandwich in acetate cloth electrical tape to keep the sheets together.

Controlling

I needed a small SBC (single-board computer), capable of driving 4 displays. I happened to have an Nvidia Jetson Nano, which has DisplayPort 1.2 output with support for MST (multi-stream transport), which means it’s able to drive multiple displays. The Jetson Nano is a powerful, tiny computer that operates on 5V power and can run a standard Linux distribution like Ubuntu.

I wrote some custom software based on Pygame to display images, with a simple web app and server to give me control over the images.

The LCD panels take EDP (Embedded DisplayPort) video input. Each display required an adapter from DisplayPort to EDP. These adapters are bulky and have a lot of functionality I didn’t actually need, like 12V power and brightness control for a backlight (which I removed from each panel) and a control interface for display settings. I also needed an MST Hub to break out 4 DP ports from the 1 DP port on the Nvidia Jetson Nano. This configuration is something I think I could make cheaper and more compact in a future revision, but it worked great for this concept.

Woodwork

I designed the lamp structure in Rhino3D and chose to make wooden parts from walnut. This makes the shade rather heavy, but the lamp is stable with the walnut base.

The shade frame, glued-up, sanded, and ready to stain.

I cut all parts for the shade and base, then shaped them on a router table. I’m not an experienced woodworker, but this came together pretty easily. I had an adventure making tongue-and-groove joints for the first time. This is the 3rd time I’ve used walnut for a project and I always like the result.

The side-edges of the frame have brass threaded inserts that enable the top and bottom to attach via M2 machine screws.

3D Printed Parts

Most of the electronic components, including the power supply, SBC, MST Hub, switches, and wiring are mounted in a 4.5” square 3D printed “sleeve” that fits inside the walnut base. There is also a vented platform that connects the sleeve to the bottom of the shade.

Drawing of sleeve and vented platform. The sleeve was printed in 6 parts. The top of the sleeve peeks out 2 inches above the walnut base and houses the toggle switches.
The sleeve in 2 parts that fit inside the walnut base. In this photo you can see most of the main components. From the right: The DisplayPort hub, Nvidia Jetson Nano, and 5V / 12V power supply. The white cylinder on the left is a ceramic E26 light bulb socket.
The sleeve, ready to insert into the walnut base. I primed and painted the 3D printed sleeve. Only the top 2 inches is visible when the lamp is assembled, so the rough spots here aren’t a problem.

If I were building this lamp for production … or if I had access to the right tools, I’d want to make the sleeve and platform out of sheet metal to improve heat dissipation.

On top of the shade, I added a louvered cover. This enables the shade to emit additional light from the top, while obscuring the bulb, which is too bright to look at directly. This also permits heat to escape. I printed these parts out of translucent PETG, which has a higher plasticization temperature than some other common 3D printing filament materials. This isn’t strictly necessary because the surface temperature of the bulb doesn’t really get that hot. Even after hours of continuous use, the temperate is <130 degrees Fahrenheit.

Drawing of shade with louvers and vented platform.
The 3D printed louvered vent while the interior bulb is off.

Making it better

This lamp is mostly a proof of concept, but it works and looks good enough that I plan to keep it and use it. If I make another, I have a few ideas for improvement.

  • Sheet metal. Replace the 3D printed sleeve and vented platform with sheet metal to help dissipate heat.
  • Replace the DisplayPort MST hub and adapters. These take up a lot of space and add significant expense (~$250 for the hub and 4 adapters). One theoretical alternative is a DisplayLink adapter based on the DL-4100, which would drive displays over USB and support EDP. I haven’t been able to find such a device on the market yet. Another option to drive displays from USB3 would be to use an SBC with Displayport Alt Mode. I would still need to adapt Displayport to eDP. Adapter boards that do this are bulky and have a lot of components because they provide power and control to the backlight. Since I’m not using a backlight, I could make a simpler adapter that just maps pins for the different connectors.
  • Finally, reconsider the closed frame design. Elroy’s shade is basically a closed box. I made this choice  to obscure the bulb and hide some electronic components like the EDP ribbon cables and adapters. An open frame design might be possible. One idea is to backlight the panels with edge lighting so I can reduce or eliminate the high wattage bulb.

BOM

Display

SBC

  • 1 X Nvidia Jetson Nano w/ SD Card

DC Power

Lights

Diffusion

  • 1 X Yasutomo Sulphite Pulp Unryu Paper Roll, Cut
  • 4 x Sheets, vellum paper
  • 4 X Frosted Acrylic 11 7/8″ X 6 7/8″, 1/8″, “90%”
  • 4 X Clear, anti-glare Polycarbonate, 11 7/8″ X 6 7/8″, 3/32”

Other

Meural Remote

I mentioned in my Digital Gallery Wall post that it would be easy to build a remote control for Meural Canvases. Here it is:

Meural Remote: Case printed on Prusa i3 Mk3. Button cover printed on Formlabs Form 2 with flexible resin. (Case is unfinished and should be sanded, primed, and painted).

This was super easy because each Meural Canvas is wifi-connected and has a tiny webserver. The commands are exposed through a REST interface. So if you know the local IP address of your Meural device, you can execute these commands from your web browser:

ON: /remote/control_command/resume

OFF: /remote/control_command/suspend

LEFT: /remote/control_command/set_key/left/

RIGHT: /remote/control_command/set_key/right/

Hardware

The remote is based on an ESP8266. These are versatile microcontrollers with onboard wifi. For this project, I knew I wanted battery power and that I wanted to recharge the battery via usb, so I wanted a board with a charge controller. I opted for this one from DFRobot (see below for an alternative suggestion).

Firmware

There are a lot of options for programming the ESP8266. For this project, I chose NodeMCU, a Lua-based firmware. I’ve used NodeMCU for a few projects. I have mixed feelings about Lua, but I really like having an interpreter when I’m debugging a new hardware project.

There’s great documentation for NodeMCU, so I won’t get into it in detail. But you will need to flash a custom NodeMCU build with the HTTP module. (I recommend letting NodeMCU Custom Builds create your build. Keep all of the default modules and add HTTP).

Circuit

The circuit is very simple. I built this on a prototype board designed to fit the ESP8266 board from DFRobot. There are 4 momentary switches (for each command: on, left, right, off). For each of these, one leg is connected to a GPIO pin. The other is connected to ground (the ESP8266 has built-in pull-ups). I also added a status LED to indicate when buttons are pressed and to blink when we’re waiting for WIFI connection.

Software

See my repo on Github.

Thoughts and learnings:

  • I didn’t give any consideration to power management for this project. The remote is always connected to wifi and draining >100mA/h. With a 800mAh LIPO battery, I’ve got less than 8 hours of charge. At the cost of some latency, the ESP8266 could be put to sleep and wake up / reconnect to wifi on button press.
  • NodeMCU is not multi-threaded. When I want to send a command to all 6 Meural devices, I have to connect to each in sequence and wait for an OK after issuing a command. It takes about half a second for each device, so the sequence is very visible.
  • Alternative hardware: One thing I don’t like about the DFRobot board is that the charge controller delivers 500mA and I can’t change it. For safety, this means the connected battery should be 500mAh or higher. The battery increased the size of my design quite a bit. Adafruit’s Feather Huzzah ESP8266 has a 100mA LIPO charger and may be a good alternative.

The Chocovibe CV100

We make bean-to-bar chocolate in our kitchen and I’m often trying out different ideas to improve our process. The Chocovibe CV100 is a vibration table for molding tempered chocolate.

Tempered chocolate has distinctive shine and appealing texture. A temper is achieved by heating and cooling the chocolate to precise points where certain crystal structures form and can be maintained.

When it’s ready to mold, dark chocolate is just barely warm enough to flow.

To level chocolate and ensure it fills a mold evenly, we often lift and drop the molds several times. It’s tedious, messy, and doesn’t always work as the chocolate cools.

The Chocovibe CV100 is an experimental vibration table cobbled together from scrap plywood, a silicone mat, springs, screws, nuts, a vibration motor, and an ESP8266 microcontroller (yes … it has wifi).

It quickly levels the chocolate. The vibration also helps nibs or other toppings sink into the bars. We’ve used it a couple of times so far and it’s a real help to our process. I may find myself building a more kitchen-friendly version of this in the future.

Digital Gallery Wall

Final digital gallery wall.
Cycling images.
Cycling images again.

My wife is a serious amateur photographer. A few years ago, we created a photo wall in her office to showcase her framed images. We always intended to swap out the images with new photos over time, but 4 years later, the same images were in these frames…

We thought about creating a digital photo wall that’s easy to update and can potentially show many more images. I bought a Meural Canvas digital frame a few months back to try it out and compare it to other options. The Meural Canvas is a 27″ 1080p LCD display wrapped in an attractive wooden frame and matte. There is a film applied to the LCD panel that improves the display. In daylight conditions, it doesn’t look like an LCD display and most people would be fooled into thinking it’s an ordinary framed image.

Meural devices have an onboard controller that connects to WIFI, so there would be no need to connect to an external display controller. They are ready-to-mount, so would require minimal hardware or wall preparation.

The Merual Canvas looked good, so we decided to make a Gallery Wall with 6 Meural Canvases.

Power

The biggest challenge was getting power to the devices. The Meural Canvas ships with a cloth power cord and large DC transformer. I didn’t want to dangle 6 cords to the floor and have a pile of transformers.

Bulky Meural transformers and cords.

Options I considered:

  • Tear apart the 100-year-old plaster wall to route low voltage power behind the wall.
  • Carve cable-routing channels into a large sheets of 1/2″ or 3/4″ MDF, mount to the wall, and paint it to blend in with the wall.
2-Conductor 16 AWG Ghost Wire on roll.

Then I found another option: Ghost Wire is flat low-voltage wire that adheres to the surface of your wall and can be finished to blend in seamlessly. They offer a 2-channel 16-gauge product that’s about 2″ wide and a little thicker than masking tape. Will it work?

A Meural Canvas runs on 12V. I measured the current consumed by a single Meural Canvas. Typical was ~450mA. Peak was 1600mA (at maximum brightness). The 16 AWG Ghost Wire product is rated up to 10A. My maximum run length is less than 7ft. If I run three devices per channel (typical 1.35A, peak 4.8A), we’ll have a maximum voltage drop of about 1% and typically 0.33%. This should work.

I opted for 2 parallel channels with 3 frames each. I used a single 200w switching DC transformer to power.

Mounting

Next, I mounted the devices to the wall with the provided cleats from Meural and I had two problems:

  • The displays weren’t uniformly flush to the wall. The mounting cleats seemed to hug the wall tighter on one side than the other. This meant that a frame may hug the wall on the left and float out an inch on the right. I don’t think I’d notice if I were mounting a single canvas, but it was obvious and unattractive when I mounted several frames side-by-side.
  • I wanted some extra space behind each frame for Ghost Wire connectors and additional wiring.

I solved these issues by mounting the cleat to a 3/4″ plywood standoff. I made the standoffs 20″ wide and attached with 5 drywall anchors each. The additional width and rigidity made it easy to level and keep flush. One of the screws in each cleat is in a wall stud.

Hiding the GhostWire seams with drywall mud. We followed by sanding and painting.
View of mounting cleats and stand-offs, plus wiring for each display after cleaning up GhostWire seams and painting. All of this will be hidden behind the frames.

What I like about the Meural Canvas for a multi-display gallery wall:

  • Attractive frame and matte. Looks like a frame rather than an electronic device. Ready to mount.
  • Very nice display, clearly tuned for this application. Makes photos look better and more natural than an off-the-shelf 4K display.
  • Reasonably good mobile and web apps. We only intend to display our own images. It’s easy to upload and manage image collections.
  • Each device connects to WIFI. Setup is easy. Each device even has a small web server with REST interface for commands, so it will be easy to make a remote or add voice-assist features for Google Home or Alexa (a practical consideration when you have 6 displays).

What I didn’t like:

  • The device itself takes 12V DC power. It comes with a very large transformer. Meural made an attempt to make an attractive cloth cord, but it still looks like a cord and casts a shadow. For future models, I hope they offer a flat cord option and perhaps a more compact DC transformer.
  • Auto-brightness and standby features don’t poll frequently enough (maybe hourly?) and work differently for different displays. For example, one of six displays may go into standby because it thinks the room is dark at 4PM. What gives?
  • 16:9. Every digital display I looked at had a 16:9 aspect ratio. Photos are typically 4:3 or 3:2. Obviously, the manufacturers are using standard LCD panels, but it’s annoying to have to crop (or let the Meural autocrop) all of our images.
  • I don’t love the mounting cleat. When mounted in landscape orientation, the Meural is 29.5″ wide and the cleat is ~3″. It feels flimsy and isn’t wide enough to level the frame properly. I think an appropriate cleat that could support portrait and landscape orientations would be 12″ wide.

A Bluetooth Mouse (for Cats)

Idea: My cat has a “bristle-bot” style toy, but it’s not a favorite. He’ll watch it as it wanders randomly around the floor, but he doesn’t really engage with a toy unless it “hides” — goes behind other objects so he can strategize about where it’s going to show up next.

The style of motion in these robots is kind of neat. There are no wheels. Instead, they operate with vibration.  There’s something insect-like about the movement.

Can I make a bristle-bot toy that I can control with my phone so my cat and I can have fun together? Yes… Well, I made a toy. I didn’t succeed in engaging my cat.

A Bluetooth Mouse for Cats in Lab-mouse White.I experimented with a couple of different designs. The parts list for this version includes:

  • Bluetooth controller (I used Redbear Labs’ BLE Nano)
  • 2 6mm 3v disc-style vibration motors for motion.
  • 2 LEDs for eyeballs and status indication (disconnect: flash, connected: solid).
  • A pair of transistors for switching current to the motors.
  • A small LIPO battery (150 maH).
  • A power switch.

The design also includes a 3d-printed mouse body and a custom PCB to keep everything compact.

Interior view.

The operating principle is that since vibration motors are mounted to the sides of the body, when a motor is engaged, the vibration will cause the legs on one side of the body to flex. If both motors operate at roughly the same frequency, engaging both motors simultaneously will move the mouse forward.

Bottom view. I left the bottom open for convenience while I was iterating on the design. I’ve also found that minimizing the amount of structure improves the amount of vibration transferred to the legs.

I designed parts in Rhino 3d with Grasshopper. I 3d printed parts with a Form Labs Form 2, using the standard Grey resin.

Render of 3d model, using transparency to illustrate 2 distinct parts: platform (with legs) and shell. 
Lights indicate bluetooth device is connected.
Sammy is somewhat interested in the mouse.

Learnings:

  • While the 2 distinct vibration motors offer some control over the direction of the mouse, it’s not particularly precise. It’s hard to steer around objects.
  • In practice, any vibration motors I tried seemed to be somewhat unbalanced (presumably operating at different frequencies), so motion is biased to one side.
  • Battery wiring initially took up a lot of space. I had to trim the leads from the LIPO battery a recrimp the JST connector.  This was a pain to learn how to do. The Engineer PA-09 Micro Connector Crimpers turned out to be the right tool.

Xaar 128 Printhead Driver

The Xaar 128 is a piezoelectric inkjet printhead used in large format vinyl sign-making. It *might* be useful in 3d printing, conductive ink, or masking applications.

Why piezo? TLDR: Most inkjet printheads are “thermal”: They work by superheating a fraction of the ink in a chamber, turning it into gas, which expands to force the remainder of the ink out of a nozzle. Superheating limits the range of materials that can be used in these printheads. Piezoelectric printheads are less common, and since they use a mechanical operation to force fluid out of a nozzle, they don’t have to modify the state of the fluid to operate, and can work with a broader range of materials.

More details on the Rep Rap wiki.

Starter source code on GitHub.

Learnings

  • While I planned to try some different materials with the Xaar 128, I started out with the Solvent Ink that it’s built for. I was mostly using used printheads that I could buy inexpensively on eBay, since new Xaar 128s are pretty expensive. Nozzle clogs were a big problem. I had to flush the nozzles every time I sat down to work. This wasn’t really compatible with an after-hours hacking schedule.
  • I used flexible flat cable (FFC or FPC) to connect my board to the printhead. I’ve been burnt by overflexing ribbon cable before, so I thought this was a good idea. But I didn’t properly anchor the connection points. After some use, I started getting erratic behavior and stalling from the printhead. After a lot of debugging, I found that the leads on one end of my cable had overflexed and would break contact at certain points in the movement. Lesson: anchor connection ends so that no flexing happens near the exposed leads.
  • I was never able to consistently push anything more viscous than solvent ink through the printheads. Epoxy or photo curing resin is much more viscous (eg. ~1000-2000+ cp vs ~10-20). This means these heads may be useful for something like depositing a low viscosity binder for powder printing, but probably not for depositing a material that can harden into a solid by itself. I’d love to find a printhead that can.