Introduction: Aurora 18x18 - the Big Brother of Aurora 9x18

About: I am an electronic artist living in Upstate New York. I work with LEDs, microcontrollers, and analog electronics to create objects that I find beautiful.
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 ***

Step 1: 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

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

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:

Step 4: 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

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.