Picture of Aurora 18x18 - the Big Brother of Aurora 9x18
There are some things that you can never stop. After building Aurora 9x18, I just could not shake off wondering, what if I made it bigger...
So I finally broke down and made a bigger version of Aurora 9x18, Aurora 18x18.

Just as the name implies, it has twice the number of LEDs. The overall dimension is seven inches in diameter. They say bigger isn't always better, but in this instance bigger is indeed better.

*** The kits and PCBs are available at http://www.theledart.com/blog/aurora-18x18 ***

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Step 1: Background

Picture of Background
Those who are not familier with my Aurora 9x18, please view its instructables here.
Aurora 18x18 is built upon the same foundation. Special PWM technique enabling just one microcontroller to control 18x3(R/G/B) channels of brightness levels, without specialized LED controller ICs.

In addition to doubling the number of LEDs, Aurora 18x18 has a built-in infrared remote receiver. Now you can control this beauty from across the room, without leaving your chair.

Step 2: Circuit & Parts

Picture of Circuit & Parts
Here are the schematic, parts list, and other technical details. Please refer to Aurora 9x18 instructables for the explanations, as the circuit is basically the extension of it.

Parts List
  • 4x 47 ohm (0603)
  • 324x 150 ohm (0603)
  • 18x 220 ohm (0603)
  • 21x 1k ohm (0603)
  • 4x 10k ohm (0603)
  • 3x 0.1uF (0603)
  • 2x 10uF (1206)
  • 1x 47uF (1210)
  • 3x DMP3098L (P-ch MOSFET)
  • 18x MMBT2222A (NPN transistor)
  • 1x PIC24FV16KA304 (* You need a PIC programmer such as PICKit 3, ICD2, ICD3 to program PIC24FV16KA304. PICKit 2 does not support this newer PIC.)
  • 1x GP1UX311QS or equivalent (IR remote receiver)
  • 1x Tactile Switch
  • 324x Tricolor LED (common-cathode)

Infrared Remote Receiver
Aurora 18x18 recognizes Sony TV remote control protocol. Sony protocol happens to be one of the easiest to implement in firmware. It's also one of the most supported protocols. Virtually all universal remote controllers support Sony TV.
I'm planning to implement other protocol as well in the future though.


Step 3: Assembly

Picture of Assembly
In Aurora 9x18 instructables, I've shown the "hot plate reflow" method. I've since found hand soldering of SMD to be quicker for the assembly of Aurora. I think without a stencil to apply solder paste, the time it takes to apply solder paste is much longer than just soldering the parts with a soldering pencil.

Of course you can choose whatever method that works for you.

*** You need a PIC programmer such as PICKit 3, ICD2, ICD3 to program PIC24FV16KA304. PICKit 2 does not support this newer PIC. ***

If you decide to assemble Aurora 18x18, take time and make sure to double check each step be done correctly. As some parts are impossible to get to once you populate LEDs on the PCB, so it's important to double check all SMD parts are soldered correctly and securely before proceeding to solder LEDs.

Power supply requirement is regulated 5V DC, 1A capacity minimum. 500mA supply might work, but I like to have some safety margin, so 1A or more is recommended. USB power supplies and computer USB outlets generally work well also.

The step-by-step assembly guide and the latest firmware is available at my website: http://www.theledart.com/blog/aurora-18x18-assembly-guide

Step 4: IR Remote Control

Picture of IR Remote Control
You can control Aurora 18x18 via IR (infra-red) remote controller. Aurora 18x18 recognizes Sony TV protocol, so just about any programmable "universal"  remote controllers can be used (in addition to the real Sony remote controllers).

The following controls are implemented:
  • Program(animation pattern) change - up/down arrows
  • Speed (of animation) adjustment - left/right arrows
  • Pause/un-pause - select key (middle of the arrow keys)
  • Direct selection of programs - numerical keys (0-9)
  • Dimming - mute key (alternates between 2 levels of dimming and normal brightness)
  • Power on/off - power key (then Aurora is off/stand by, pushing any keys will turn on Aurora)
Two of the ten programs available are audio (color organ) functions. Without the Audio Interface connected LEDs will stay blank when audio modes are selected.

Step 5: Audio Interface

Picture of Audio Interface
Wait, there's more!

A new, audio interface function is also added (requires separate interface), making Aurora 18x18 the ultimate color organ.

The audio interface connects between the Aurora and the power supply. It has a 3.5mm jack to accept connection from just about any audio source; iPod, computer, stereo set, etc. There's also a thumb-wheel type trim pot for easy audio sensitivity level adjustment.

aniketkatkar6 months ago

Awesome work! Looking forward to make one :) It just looks perfect.

hahahaha "bigger is indeed better" ... so true dude! great work i think i am going to build something similar after finishing my exams ^^
GlowWireGuy2 years ago
aanuit3 years ago
Hey Ledartist, great upgrade!

I don't understand something about the PWM concept.

You say the PIC runs as 32 MHZ, so 8MIPS.
You write that the width of the chart in your 9x18 instrutable is 8.1 ms.
8000000 / 1000 * 8.1 = 65536
SO the width of the chart is 65536 instructions.

There are 256 PWM steps and each step is split into three substeps.
65536 / 256 / 3 = 85
If the maximum width of each substep is 85 you cant increase the length of each pulse 256 times, but in the graph in the 9x18 instructable, this is what happens.

What am I missing?
ledartist (author)  aanuit3 years ago
PIC24F is 16 bit microcontroller, running at 32MHz gives 16MIPS. (the architecture is different from 8 bit ones)  Shortest pulse this PIC can produce is 62.5ns.

Not sure if I understand what you are saying, but my implementation on Aurora only has 128 levels of brightness levels.

R/G/B channels each go through 127 varying width of pulses to form equivalent of one phase of PWM output. The basic idea is to control the PWM output in exponential curve, instead of linear typical of usual PWM. And to control multiple LEDs, hardware produced pulses are multiplied with the software controlled output pins to keep the timing precise, and reduce the processing time.

My implementation also has a benefit of reducing visible flicker, by breaking up each PWM cycle into subcycles - similar to spread spectrum technique used by specialized LED controller chips.
blackgear073 years ago
hey ledartist, great work!
can you send me/ or post a complete list of parts for the Aurora 18x18 like the 918-Bom.csv for the dikikeys site.
please, i don´t find the corecct parts.

best regards and thank for the help
ledartist (author)  blackgear073 years ago
Parts come from a few different places now. Let me know which one you are having problems locating.

Thanks, i´ve already the parts. are these the correct ones http://flic.kr/p/bN2bgz
Oh no I've forgotten the transistors and the wrong PIC MMBT2222A ordered.
ledartist (author)  blackgear073 years ago
looks good to me...
BlueRock3 years ago
Beautiful art!

Do you have any plans to make a larger version of either the 9x18 or 18x18 i.e. the same number of LEDs but spaced further apart?
ledartist (author)  BlueRock3 years ago
Possibly, in the near future...

venecha3 years ago
This is just amazing! So much went into it! Definitely going on my project list!
gserrano7013 years ago
Great job, thanks for sharing.
pahosler3 years ago
Amazing and beautiful, this is going on my future project list!
ledartist (author)  pahosler3 years ago
sreeci3 years ago
Aki San,
18X18 looks great.
What is the price of fullly assembled unit?
ledartist (author)  sreeci3 years ago
Hello Sree,

How are you?

I have not decided if I sell assembled units. It takes hours to assemble those, so I can't make that many...

jeff-o3 years ago
Another stunning piece of work. I especially love the colour organ mode!
ledartist (author)  jeff-o3 years ago
Thanks Jeff!

Yeah color organ mode looks a lot better than I imagined. The idea was around for a while, then I finally did it, and I'm glad that I did.

yours31f3 years ago
Think I could buy a PCB prepunched from you?
ledartist (author)  yours31f3 years ago
I will make the PCB available for purchase very soon. Check back my website http://theledart.com for info.

ryckmans_t3 years ago
A thing of beauty. Thanks for sharing
ledartist (author)  ryckmans_t3 years ago
Thanks for looking!
mikeasaurus3 years ago
Looks great!
ledartist (author)  mikeasaurus3 years ago