Picture of Aurora mini 18

My obsession of this year is full-color LED. I have made Aurora 9x18 as a result. As much as I love the scale of Aurora 9x18, I also wanted to have something smaller, perhaps something that can go on a costume.

Here's Aurora mini 18. It has 18 full-color/RGB LEDs on a smallest possible circle. With a single PIC microcontroller, changing 18 RGB LEDs smoothly is reaching the technical limit. With the new PIC with wider supply voltage, the circuit is simplified compared to Aurora 9 bar, and use of two AA or AAA batteries (3V operation) or one Lithium battery is now possible.

Step 1: Concept & Circuit

Picture of Concept & Circuit

Like Aurora 9 bar, Aurora mini 18 borrows its circuit from Aurora 9x18. Operating principle is exactly the same. Just extended the hardware and software to control more LEDs.

One of the new 24F line of PIC microcontrollers is PIC24FV16KA302. Unlike the similar PIC24F series controllers which are 3.3V limited, this controller can operate fully up to 5V. This eliminated the need for the 3.3V voltage regulator, and simplified the LED driving circuits. The resulted circuit with fewer parts count made this Aurora to be very compact.
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theCow12345 months ago

Hey i built it and everything works great except that there is no red. Any idea what could be the problem?

ledartist (author)  theCow12345 months ago

The LED leads are very close together and easily shorted by solder. The shorts are not always easy to see, but cleaning the soldered PCB with alcohol (or PCB cleaner) helps examin the soldering visually.

voblak9 months ago

Hey, is there a way, you can send me gerber and drill files, so I can make PCB on my own?

talonsblade2 years ago
I would like to use something like this to do one of those lightup christmas trees in my ard but i would need to connect a string of lights where each of those leds would be. is this possible? also can i program it to flash on and off at a certain time so i can make it flash to music?
ledartist (author)  talonsblade2 years ago
Connecting more LEDs to Aurora mini 18 is not very straightforward. Of course it's probably not impossible, but I leave that as a challenge for you to solve...
As for music sync, check out Aurora 12 bar with Audio Interface.

Ploopy2 years ago
Ploopy2 years ago
CR15P332 years ago
there is a girl in my class named aurora that iv`e had a crush on , now i know what to give her.
ledartist (author)  CR15P332 years ago
Cool! Was she also "mini"? :)
LOL a little bit
lmperkins2 years ago
I just finish incorporating the mini 18 into an infinity mirror. It looks great if I do say so myself.
ledartist (author)  lmperkins2 years ago
Does look great! Congrats!

rhoaste2 years ago
I would like to know more about the technique you are using to handle the PWM. Is the source code available for this project ?
ledartist (author)  rhoaste2 years ago
Email me at aki (at) theledart (dot) com and I will email it to you.
lmperkins2 years ago
Just finished building mine from your kit. That's really cool. Makes me a lot more interested in the 18x18. That's the fifth kit of yours I've assembled. I continue to be pleased with the quality of design, construction and function of all your kits. Thanks and keep up the good work.
ledartist (author)  lmperkins2 years ago
Thank you so much for your support!
Hearing people successfully building my projects makes me really happy.

Just completed it and programmed it, but it just do red and purple, what could be wrong? mostly red...
ledartist (author)  Anders7309173 years ago
First, check to see if there are no shorts between LED leads. Use a multitester set in Ohm (k Ohm) range and check the resistance between them. If it's very low like 0-10 ohm, you have a solder bridge somewhere.

Also check to see the Q1G (transistor in the center). It's easy to have loose connection on the transistor leads. You can apply a small amount of flux on the leads and give a little heat from a soldering iron.

Lastly, you should check the soldering of the PIC. Pin #21 drives the green channel, so pay extra attention to this pin. Again you can apply flux, and give a little heat on the lead to make sure there's a good bond.

Hope you found the problem.

ledartist (author) 3 years ago
Aurora mini 18 kits are now back in stock! Thank you for waiting!


nerd74733 years ago
what website do you go to for the kit?
ledartist (author)  nerd74733 years ago
Here's the info:

It's out of stock right now, but will be available by February.

Nemissis4563 years ago
can you use other LEDs too?
and whats the diameter of the pcb?
I'll rephrase: is it possible to mount single color LEDs on it, like for example green ones, while at the same time keeping the animation program the same.
ledartist (author)  Nemissis4563 years ago
You can. You can insert ordinary single-color LED into the PCB, only using two of the four holes. This will connect the LED to the blue circuit, leaving red and green open. So you will get the blue-only animation in the color of your choice.
Note that the placement of the LED will be a bit off if you do this...
ledartist (author)  Nemissis4563 years ago
Not sure what other types of LEDs can fit...
The diameter of the PCB is 50mm.

dstinger3 years ago
This is such an awesome lighting effect! I am working on a project having to make lighting effects with an Arduino board. Is it possible to control the Aurora 18 mini with an Arduino board?? If so how would I accomplish this?
ledartist (author)  dstinger3 years ago
I guess one can use SPI or something to communicate between Aurora and Arduino. I will look into it for the next firmware upgrade.

What sort of things you want to control from Arduino?

I had wanted to control the Aurora sequencing of colors with the Arduino. I didn't know how the PIC worked and was wondering if I could use an Arduino to replace this as the controller. I guess I would need to look into the SPI. The other parts of the project are controlling a string of LEDs with an Arduino. I would need to know if it would be a possibility by this next week for presentations. I had just found this lighting effect and thought it would be an awesome thing to add!
ledartist (author)  dstinger3 years ago
To control Aurora with Arduino (or any other digital devices) Aurora has to be able to take commands. I have to correct what I said in that SPI is not possible because it uses at least two I/O lines, where Aurora 18 only has one I/O pins available as external I/O (one that connects to the switch).
You can still use this pin to receive data using async serial.
As for replacing the PIC with Arduino, I guess that's possible, but not an easy task. PIC24F used here is a bit more capable than Arduino...

Hope this makes sense...

Really nice design. I'd love to buy a kit but am worried I will probably ruin it with my soldering skills.

Would you consider selling a kit with the surface mount suff pre-soldered?
mr nick - send me your kit and I'll assemble it for you - no charge. These go together in about 30 minutes. I have built (2) of the Aurora 9x18s, a 9 bar and the Mini 18. If you are intersted, drop me a PM or email - rclay701 at gmail dot com.
ledsign3 years ago
It's very beautiful!
Hugu3 years ago
PCB layout? eagle files?
thepelton3 years ago
That would be neat to put on a bicycle for riding at night.
cinezaster3 years ago
looks cool, Is it possible to show a photo of the back?
ledartist (author)  cinezaster3 years ago
Here - for now... I will upload a better picture later.
dombeef3 years ago
Do want. Do want do want do want.

Any chance you might be selling a kit for this?
ledartist (author)  dombeef3 years ago

Yes! Just posted the details in the forum.
It says Aurora 9x18 being assembled...hmmm...

ledartist (author)  blinkyblinky3 years ago
Reused the pic from Aurora 9x18 instructable...
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