15x15 LED Board

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Here is another video about the project: https://www.youtube.com/watch?v=NjxL4i6Dl8o

Overview

This project is one among others built by the Maker Club at my school.  Two people worked on this project: me and my friend Anand.  We wanted to build a LED board because Anand is about to go to college and wants to have this in his dorm, possibly functioning as a display for music equalizers.  

We participated in Bay Area Maker Faire 2017 with this project. I was really delighted to see that there are many people who also are trying to build a LED board, and  being able to talk to them and sharing my experiences of building the board with them was for me a pleasure.

How it works/ how to build one

Please visit the How-To section.

Workspace

We used the Fab Lab at Santa Clara High School to build the project.  Fab Lab is a makerspace available to all students at Santa Clara High School.  We were able to discuss the details of the project, solder the LED strips, and test different patterns in Fab Lab.

Image credit:  Terrell Lloyd @49ers

 

Reflection

Through building the LED board, the most important thing I learned was probably being creative in terms of solving a problem.  When the hot glue gun did not stick the LED strips to the board, we tried out epoxy glue.  When epoxy glue was too slow for us, we used adhesive squares.  When we realized we had enough LEDs, we also improvised to build a 15x15 board instead of a 10x10 board, which was decided after some calculations about the current and our power supply.

Thanks to Matthew Dalton and his team for filming & editing the show & tell video! A more explanatory and more comprehensive video will be uploaded in mid-August.

How-to: 

Basic Setup

The 5V and the ground pin is wired in parallel, while the control pin is wired in series.  The 5V and the ground pin are connected to another power supply.  The control pin is connected to the Arduino, which is then connected to the computer with Glediator running.

Parallel vs. series circuit

We originally wired both the ground pin and the 5V pin in series; however, our advisor suggested that the great amount of current (about 3A) through the 2 pins when wired in series would possibly burn out the wire. Thus, we added bridges between LED strips to wire it in parallel to alleviate the current passed through one LED strips.

Manual Bit-mapping Vs. Glediator

To display a logo, the Glediator software does a poor job in terms of downsizing the image to a lower resolution; thus, we manually bitmapped the image through Photoshop so the logo is recognizable even with only 225 pixels.

How can 1 pin control the colors of 255 LEDs

The LEDs are controlled by hexadecimal RGB values, with 8 bit each to represent the amount of red, green, and blue of a color. The Arduino pin implements the serial protocol, which is basically a shift register. In stead of each LED having a specific address to send the RGB values to, each pin gets enough data before passing the data onto the next pin. The advantage of using the serial protocol is that each pin of each LED does not have to have an address explicitly assigned, making this a scalable system for adding more pixels.

Difficulty: 
Share a "Show & Tell" video.: 
https://youtu.be/BKLn-uyeOJI
Collaborators: 
harry47341
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Tools: 
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Soldering iron
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wire cutter
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multimeter
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epoxy glue
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5V 10 amp power supply
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led strips
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225 leds
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wood board
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Team member name: 
harry47341
What role did this person play on the project?: 
coded the Arduino, learned how to use Glediator, and bit-mapped the images
What role did this person play on the project?: 
soldered most of the project, helped code the Arduino, provided materials
Anonymous member name: 
Anand Jain
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Teaser: 
This is a LED Board consisting of 15 LED strips that, connected to an Arduino which is then connected to a computer, can display various patterns, texts, and even GIF images.
Aha! moment: 
Originally, to display patterns through an Arduino on a series of LEDs, one would have to code each specific LED. This process is tedious and prone to mistakes. Luckily, we discovered a program called Glediator, which has a user-friendly interface that can display different patterns and images. The Arduino is coded to talk directly to Glediator.
Uh-oh! moment: 
On Maker Faire's Friday afternoon, one of us accidentally pulled the entire board without unplugging the power supply, and one of the strips disconnected with the cables connecting them. I spent the entire Saturday morning trying to attach a new piece of LED to the strip. The first try failed because I attached the LED the other way around :(
Show & Tell video as default: 
Creation Date: 
Thursday, June 22, 2017 - 17:05