Cardboard Tube Bench

Inspired by this article on inhabitat, I took a crack at building a cardboard tube bench with some tubes found in the recycle bin and some plywood. Instead of leaving the tubes a natural color, I decided to paint them with acrylic paint to give them some color and some water resistance.

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Spaceship Menorah

Spaceship menorah dancinf.jpg

Inspiration

IMAG2993.jpgThis project started with the idea of creating a wall mounted sculpture using seven 5 meter long pixels controlled by an ESP8266 and an MSGEQ7. I got inspiration from Garrett Mace, Northern Lights Electronic Design, and another ESP + MSG project.

This idea was developed after explorimenting with the Tower of Power project that was in progress at the time.

Seven

The number of LED pixels was chosen because the MSGEQ7 chip outputs seven analog voltages corresponding to audio input frequency. Since I wanted to mount it to a wall in my house, I decided that each five meter strip needed to be doubled back on itself. To add some extra geometry, I decided to break the tubes into different lengths and arrange them in a shape that looks like a spaceship. When I learned that Jewish menorahs (not the ones used for Chanukah) use seven candles or lights, I decided to dub this project “Spaceship Menorah”.

 

sketchup sculpture.png
I used Sketchup to visualize Spaceship Menorah on my wall before constructing it.
Tinkercad.jpg
I used this diagram made with Tinkercad to help me visualize and get some measurements for the plywood supports.

Construction

The sculpture’s PEX tubes are laid out on the floor using some cardboard discs to help visualize translucent acrylic supports.
Component Layout
Bamboo sticks and coins were used to lay out the proportions of the sculpture. I started by positioning three power supplies in a paper footprint of control box. I later removed them in favor of one repurposed PS3 power supply.
Plywood structure construction
I started gluing plywood together using wood glue, but soon switched to hot glue.

PEX tubes are not very rigid, and gravity will easily bend them if left unsupported. I wanted to create some structures that protruded from the wall a few inches in the center, and not so much at the edges. I used thin plywood  which is sold as floor underlayment. This product has a smooth surface, but it’s easy to get splinters in your hands when cutting and shaping it.

Support structures.jpg

This is a plan for the central circular support structures. The cardboard tubes (orange) are different lengths to set the PEX tubes at different distances from the wall.

Parts List.jpg

Milky Acrylic Circles

Cutting acrylic can be difficult without the proper tools. I have seen several Youtube videos of makers successfully using laser cutters and bandsaws to cut acrylic into round shapes. I did not have success using a jigsaw with a fine tooth blade, so I used a circular saw and a belt sander instead. I fitted the saw with a 144 tooth blade which tends not to crack the material as it is being cut. After I roughed out a circle using the saw, I was able to make it round-looking using the belt sander.

Tubes Going Up!

The tubes are held away from the wall using three “V” shaped plywood supports each “V” is made of three parts which are screwed to the wall. The bottom “V” is not yet installed in the photo below.

Pex tubes going up_2

To attach the PEX tubes to the plywood supports, I cut 41 1″ by 2″ pieces of acrylic and screwed them to the plywood with small wood screws. I roughed up the surfaces of the acrylic and the PEX with a rotary tool, then stuck them together with hot glue. This has worked for the most part, but some of the tubes are under a slight spring pressure. One tube fell down after a year. If I did it again, I would make some 3D printed clips that do not rely on hot glue.

LED Control Box Construction

I built a control box which houses the MOSFET boards, the microcontroller, an MSGEQ7 board, a re-purposed Playstation 3 power supply, and the “waterproof” connectors. I discovered that the power supply needed some ventilation, so I added a buck converter and two 40mm fans.

LED driver enclosure.jpg
For the acrylic sides, I cut a strip of acrylic, heated it with a heat gun, then used a bucket to form it while still warm. Hot glue holds it to the plywood.

First LED Light!

First LED light.jpg

After wiring everything up, I held my breath and flipped the switch! Nothing went bang, so I installed Jason Coon’s “Tree V2” Code to the ESP8266. It worked! But after a few minutes…

I Smoked Some MOSFET Boards 😦

smoked board.jpg

I let the magic smoke out of two MOSFETS before discovering that the long wire lengths of the LED strips create a large inductive load. After the first failure, I replaced what I thought was a bad component with one of my precious spare boards. After the second failure, I started to wonder if I was doing something wrong. I removed the smoked MOSFET and replaced it with a similarly rated one that I had on hand – an IRF540. This works well, but I can see a slight brightness difference on that channel. For me, it adds to the unique quality of the Spaceship Menorah. I opened up the control box and added two large capacitors in parallel. Thankfully, I have not had any more MOSFET failures since performing this fix.

Trouble With WS2811 “Dots”

My original plan was to have separate LED “Dots” at the center of each acrylic disc. This would double the amount of addressable pixels – from seven to 14. When I installed and tested these dots, I was not able to get them to to a state of working order. They were constantly flickering. I was using a 3.3v input from the ESP8266 for the data line, so I tried using an Arduino with a 5V data line but had the same trouble. In the end, I removed the “dots” and saved these pixels for another project.

Finished Product (for now)

Spaceship menorah danccing.jpg

Spaceship menorah danccingg.jpg