Introduction: Aurora 9 Bar - the Essence of Aurora

Picture of Aurora 9 Bar - the Essence of Aurora
Since the introduction of Aurora 9x18, I received many requests for the kits and PCBs. I'm still quite undecided about making those available for a few reasons. However I really want other LED lovers (ok that might sound too much :) to be able to build one themselves.

So I came up with Aurora 9 bar. It's a bare essential version of Aurora 9x18. In fact the circuit is almost exactly the same (with a lot less number of LEDs of course). Even the firmware is essentially the same. So it has the same super smooth color fades as Aurora 9x18.

Step 1: Concept & Circuit

Picture of Concept & Circuit

Aurora 9 bar's circuit operates in the same exact way Aurora 9x18's does. Same PWM theme, same refresh rate, etc. Please refer to my Aurora 9x18 Instructable for the details.

Aurora 9 bar took one LED out from each of Aurora 9x18's 9 circles. Only difference in the circuit is that it uses BJTs instead of MOSFETs for the high-side switch (to save cost). Because there are only 9 LEDs total, the current requirement for the bus controllers is much lower.

Everything else is the same. So if you somehow manage to hook up more LEDs to Aurora 9 bar, it will look like Aurora 9x18.

Step 2: PCB

Picture of PCB

Aurora 9 bar uses surface-mount technology (SMT). If you've never built anything with SMT, this might be a good opportunity to try out. You will most likely realize that there's nothing to fear about SMT.

The high-quality, custom made PCBs, as well as kits are available at reasonable prices. Please view the details at "Kits" section of the forums.

Step 3: Parts

Picture of Parts

Here are the list of parts, or BOM. All except two items (LED and switch) are available at Digi-Key (, and the rest are at SparkFun Electronics (
You can download BOM files that can be uploaded to Digi-Key for quick ordering.
  • 16x 120 Ohm (0603)
  • 21x 1k Ohm (0603)
  • 1x 10k Ohm (0603)
  • 2x 1uF (0603)
  • 1x 10uF (1206)
  • 1x AP7333-33 or AP7313-33 (3.3V linear voltage regulator)
  • 3x MMBT2907A or equivalent PNP transistor
  • 12x MMBT2222A or equivalent NPN transistor
  • 1x PIC24F08KA101 (SSOP)
  • 9x 5mm Tricolor LED (common-cathode) (SparkFun COM-09264 should be identical)
  • 1x 5-way Tactile Switch: COM-10063 (Available at SparkFun Electronics)
  • 1x 5V regulated power supply, 4 NiMH batteries & case, or USB cable
  • 1x 2 pin Molex header (right-angle recommended) (optional)
  • 1x 2 pin Molex connector with corresponding terminals (optional)

There are many places to purchase LEDs. I source LEDs directly from China via AliExpress. Takes a few days for delivery, but the prices are great. (If you are purchasing a lot of LEDs.)

You can substitute transistors if you have something compatible.

The kits are available at a reasonable price as well. Please view the details at "Kits" section of the forums.

Step 4: Tools & Supply

Picture of Tools & Supply
  • Tweezers
  • Soldering iron
  • Solder (flux core. go for the highest quality solder you can afford.)
  • Soldering flux (Use high quality flux. Low quality flux causes problems! ChipQuick brand recommended.)
  • Wire cutter (I recommend this one.)
  • Microchip PIC programmer (supports PIC24F08KA and capable of In-circuit programming through a standard 6-pin ICSP connector, such as PICKit, ICD 2, ICD 3)
  • Computer running Windows
  • Magnifier visor or other visual aid device (optional, but highly recommended)
  • Molex crimper (to make your own power supply connector cables)

Step 5: Notes on SMT

Picture of Notes on SMT

If you are already familiar with SMT, you can skip this step.

There's no need to use reflow method (solder paste & bake) to build the SMT version of Aurora 9 bar. Since there are only a few components to solder, it's quicker to just hand solder everything.

It's very helpful to use high quality flux when you solder SMT components. I'd say it's the key to successful hand soldering of SMD. Apply a small amount of flux to the PCB pads before placing the device, then solder. If you haven't done this before, you'll feel like your solder skill has suddenly improved :)

Step 6: Assembly

Picture of Assembly

Please download and print the "Parts Placement Chart". Use this to identify/guide where all the parts go.

I recommend following the order listed. Also be mindful of electrostatic charge. Use anti-static desk mat if you have one. Or place aluminum foil under the PCB like I do.

Mounting the LEDs
If you want to mount the LEDs very close to the PCB like I do, you need to cut the leads. Cut the leads right where they get thick. Please refer to the picture.
The leads of LEDs are very close together, so easy to create solder bridges when soldering. Get your solder wick handy and make sure there are no shorts.

Washing the Board
Solder everything _but_ the switch. Then wash the PCB with water. I've had many problems of LED flickering a while after the assembly due to the slight short circuit caused by flux residue. Even with high quality flux, solder joints can accumulate dust, and with moisture in the air creates electrical conduct. The problems went away after I started washing my PCBs.

Wash PCB in warm water and detergent. Use old toothbrush to scrub the solder joints, making sure all of the flux is off. Rinse very well with warm water, and dry completely using a hair dryer. (Very important)

If you solder the switch by mistake, don't wash the board. Switches can not be wet. Instead, use cotton swabs and alcohol or flux cleaner to clean the flux residue.

After the PCB is cleaned and dry, solder the switch, and assembly is finished!

Step 7: Choose Power Supply Connection

Picture of Choose Power Supply Connection

The supply needs to be 5V regulated type. Unlike Aurora 9x18, the current rate can be as little as 150 mA. You can remove the plug from the AC adapter and attach an Molex plug like I did, or solder the leads from the power supply directly to the PCB. Square pad is negative, and round pad is positive. Be very careful not to apply voltage in reverse polarity! It may (or may not) destroy the unit - can't tell - I never tested.

You can also use NiMH batteries to power Aurora 9 bar. 4 NiMH batteries connected in series provide just about 5V, perfect power supply for most circuits that call for regulated 5V power.

Another cool thing is to use USB power. (See the photo.) Aurora 9 bar draws less than 150 mA, so most (if not all) USB ports should work.

Step 8: Electronic Check & Programming the PIC

Picture of Electronic Check & Programming the PIC
Check carefully for bad solder joints and parts placements errors. Before moving on further, take out your multi-tester and check the Ohm reading of the power connector and ICP connector pads. Make sure there are no shorts.

Then fire up your PC, launch Microchip IDE and program the PIC microcontroller on the PCB with the HEX file provided. You need to connect a 5V power supply. I use a straight 5 pin header to connect (square pad marks the MCLR pin) the programmer. Mine is ICD 2, but any compatible programmer such as ICD 3, PICKit 2 and 3 should work.

Just use the PCB holes/pads as though they are the female connector. Give a bit of tension sideways to make sure the electrical connection is stable.

You need to use "high-voltage programming" mode. IDE defaults to low-voltage programming mode for the device, so make sure to change the mode. You will find this option in IDE, under "Programmer" menu -> "Settings". On "Program Memory" tab, check "Use high voltage on MCLR".
(If your programmer is an older one like mine, you also need to make sure that the programming voltage for high voltage programming mode is below 9V. Microchip suggest using high-speed shunt regulator on MCLR pin to clip the voltage - I found this overkill - I just put a 8.2 V zener diode between MCLR and GND. It works!

If you get the following:

"The following memory regions failed to program correctly:
Configuration Memory
Address: 00f8000c Expected Value: 0000007a Received Value: 000000fa
Programming failed"

then you are not using high-voltage programming mode. Please double check the setting (see the screen shot) and try again.

If all is well, you'll see the IDE reporting successful programming. If not, go back to more inspection.

Step 9: Enjoy!

Picture of Enjoy!

I hope you enjoy the beautiful and hypnotic color patterns as much as I do. I have 5 well tweaked parameters in the current firmware to chose from. The up/down of the switch changes the pattern, while left/right moves of the switch changes the speed. Push of the switch pauses/un-pauses the movement. Hold down the switch for two seconds turns the lights off.

There might be more functions added to the firmware, as there is a plenty of room left on the programming memory.

The 5 pin header contains two pins that can be used as analog inputs - so there are possibilities of adding interactivity based on analog input, such as sound. Hackers are invited.


LumiL1 (author)2016-04-26

Anyone know how to implement the lightning pattern with neopixels and arduino?

Zwurmi (author)2013-06-24

I found some LEDs with common anode, so I modified the schematic:

left: orginal rigth: modefied

Do you think it works?
Btw I can't write programms for PICs and can't read assembler.

Thanks Zwurmi

ThatCatMan (author)2013-05-02

When I say sell this, I really mean all ready pieced together. I could probably never be able to solder so many tiny things. Nor could I even keep up with the tiny parts in the first place...

ThatCatMan (author)2013-05-02

You should totally sell this online like on Sparkfun or something. There is no way I could do this all any time soon, but it is so amazing, I would love to have this! :D

blinkyblinky (author)2012-11-06

Did you remove the zip file? I recently learned a new programming language and want to try this project out with it. I downloaded it before but I have upgraded to a new OS and so, lost the file.

P.S. What is the music used in the video?

ledartist (author)blinkyblinky2012-11-07

I don't know what happened, but I uploaded the file.

The music on the video is one of the tracks that came with the video editing suite (Final Cut Studio). The name of the track is "Reverse Chill".

blinkyblinky (author)ledartist2012-11-07

Could you upload it on your website or something like a Google Docs drive? Thanks.  

ledartist (author)blinkyblinky2012-11-07

It's already uploaded - under step 8.

blinkyblinky (author)ledartist2012-11-07

Thanks a million.

ptkhoi (author)2012-02-28

what PIC can i use instead of PIC24F08KA101 ?

I can't find PIC24F08KA101 in my city :(


blinkyblinky (author)2011-09-24

Thanks so much. Will try.

blinkyblinky (author)2011-09-24

Could you place the source code for this project so I could mod it for use with the PIC16C55?

MiladSafa (author)2011-09-17

Hey, guys, I have assembled the kit, but when i try to programme it is gives and error saying Device Id mismatch it says 000000 something and it should be 0000142 or similar, any help would be tremendously appreciated

i used pickit 3.

ledartist (author)MiladSafa2011-09-17

Check to make sure that you are using high voltage programming mode. See the second picture (screen shot) in Step 8.
Also make sure that you have connected 5V power supply to Aurora.


roketlights (author)2011-08-11

hey it doesnt specify which way the led should go

ledartist (author)roketlights2011-08-11

Take a look at the diagram, "Aurora9bar_PartsPlacement". LEDs have a flat side when you look from the top. Match that with the diagram.


roketlights (author)2011-08-05

im trying to figure out how to program..
i bought 2 of theese kits can you helpme program it? i have no idea how?

ledartist (author)roketlights2011-08-05

You need PICKit or ICD, or a clone programmer.
Once you have that, it's very straightforward.


roketlights (author)ledartist2011-08-06

thanks! looking forward to your lights! please send asap :DDD

-chase- (author)2011-07-25

Hi -

Love the size of this - width wize.

I've been looking for something to create a Spoke with but most are too wide for what i want to do.

Such as this one or this one...

JSo I'm curious if your design could:

a) be made longer to go from center of a wheel hub to the outer perimiter b) be made programable to show not only images when used as a spoke POV as the others linked to above, but also with the added plus of being able to display video as a POV

- with out much more width being added to the circuit board?

I'm sure this can be made to be a spoke POV but the width and what it would take to mod the circuit is the real question i'm curious about and what your thoughts are on how to go about doing so.


ledartist (author)-chase-2011-07-25

I have given a thought of adding a little circuit to make this into a POV display. In fact, I'm about to test it.

a) If by longer do you mean more LEDs? The same design/software can be scaled to control more LEDs. I've tested with 18 LEDs. Of course you need a microcontroller with more I/O pins.

b) Never thought of showing video! May be my next challenge... Can be done without adding anything to the board, I think.


-chase- (author)ledartist2011-07-25

Yeah video... ;0)

With your system - i bet it would be supior to anyother if done right.

The bike i want to put one on and i;ve looked at many - as they say patience is a vertue - then i saw yours - i really like yours. and want to make it but...

I want it to fit the wheel - let me see if i have a pic of the bike on instructables
one second...

yup got one - you can see the wheels in this one.
They are 26" wheels but as you can see they are tri spoked.
putting 3 would lower the spin rate needed to see a picture and i believe video.

Putting them on boths sides - would look just ooh so cool.
especially when i paint them or the bike in total in semigloss black.

it's just the thought i'm having - and i want the leds to go from center rim to outer rim.

Since you made one with 18 leds - how long did the board come too?
I'll messure my wheel spokes tomorrow or the next day and let you know how long they are.

And thanx for answering and posting this instructable.
I've waited a good while to find one that really suits my bike and what i wanted. looks like i may have found it with yours.


ledartist (author)-chase-2011-07-25

Is that your bike? That's nothing like what I call bikes around here in Brooklyn ;)

Let me know the length of the spokes...


-chase- (author)ledartist2011-07-26

Yup that's my bike - i moded it a little by adding the scooter trunk.

I bought it second hand from a very nice canadian - you can't buy them in the USA - never could - but he brought two of them down while vacationing here. I got one of them and i think he took the other one back with him.

It's China designed and built - real tuff to get parts and real heavy but...
I like it - it goes farthur than the ones you can buy here in the states so fair, 90 miles on pedal assist.

I'll be heading over to where i keep it later - and take the measurements.

I wish i could just drill the spokes and have the leds come from the inside of the spoke - i looked - can't be done with out major work that would probably destroy the wheel.

But your leds - unlike the others i linked to - would look real sweet since they are narrow - i can make them look good aesthetically i think and hide them pretty much.

I've already thought of a water proofing idea and possible casing to put them in which i could just put two screws to hold them to the spoke or even velcro them with industral velcro in needed.

I'll get back to you asap.
thanx again ledartist.

-chase- (author)-chase-2011-07-27

Hey ledartist - i have the info you require.

7' for the rear and 8' for the front... however the front with that 8' on the inner i'd say 1/2 to 3/4 of an inch has only about 3/8inch of clearance due to the disk brakes.
but looking at your kit design - i do believe the end that doesn't have an led on it - where the power hooks up - will slide in there nicely. but i'm not sure - obviously i don't have it in hand to check.

Thepokes are not as long as i thought they would be on this bike, considering my 28' regular bike is probably around a foot or so. and a regular 26' is probably a good 11 inches or so.

anyhow have you given much thought to how to desplay pics and the right chips etc or even video?

I bleieve one of the kits that the person used in the POV link i posted above - they have one that does video... maybe you can get some ideas from that.

My thought is though since yours fads from one color to the other it should look one heck of a lot sweeter... well at least the way i'm envisioning it working.

let me know what you think and how to go about it. or if you deside to make it - hopefully you'll post an instructable on it.


ledartist (author)-chase-2011-07-27

I guess a bit longer bar would be ideal?
I haven't made a progress on the POV idea yet. I have to wait for a hall sensor to arrive.
It's should be a minimal addition to Aurora 9 bar - hall sensor to detect the position, and software tweak.

Have you thought about how to power the circuit on the bike? Battery neat the LEDs on the wheel?


-chase- (author)ledartist2011-07-28

I've thought of it several times and of a few ways to power it.

The bike itself is 36 volt - pulling off that would be pretty simple and then just step it down.

What i would like to do and would probably be best - thoguh it would be more involved is to use this switch i saw once - don't know the name of it - which is a hurtle to go over.

It has a small tube with a spring loaded ball bearing inside - the bearing rolls against t contact strip - they use them just for such purposes.

I could put the contact strip whic is very small - maybe an 1/4 wide - looks like a gasaket almost - insulated on the back side - copper on the front is the way i've seen them before.
 and put the bearing side on the forks or wheel support. - then it would be easy to tun leads to any power supply - i might even add a power supply in the rear trunk at 12volt - i want to put leds in the reflector areas and have already bought them for the two main tail lights i guess you call them.

But as mentioned - i don't remember the name of what those type contacts are callled - i've searched the web but haven't found them yet.

that's my thought anyway -the other way is to tie a 9 volt battery to the wheel - or what ever voltage battery pak it can run on to the wheel.

I know other builders have done it that way - but not the way i want to do it as mentioned. ;0)

can't wait till you get the hall sensor in - i'm anxious to see what you develop.

Btw - i was reading one of your other instructables - you actually make these kits don't you? This is not something your going out and buying - your making the circuit board and all - if i'm reading it right.

Thats so cool - origianally i thought you were saying there were other kits available and custom kits available from some manufacturer or supplier you delt with.
all i can say is Wow! That's great - great work - looks absolutly great too!
Very professional looking piece of circuitry and board.

I'm totally impressed

ledartist (author)-chase-2011-08-04

Sorry I didn't mean to ignore your last comment... Just got busy.
I will tackle POV soon, but can promise as to when. You will see it here on Instructables for sure though.


kgroce1 (author)2011-07-26

Now this might sound like and odd question but what do they look like when spun? I have a project idea that has been using fixed color LEDs in a bar and this would be awesome if the colors stay mixed.

ledartist (author)kgroce12011-07-26

You'll see dots when you spin Aurora 9 bar. This is due to the PWM - LEDs are blinking at a fast rate.
As far as I can tell those dots keep the same colors, though.


crony_mk (author)2011-07-25

excellent!! muy bueno amigo!! :)

thirst4know (author)2011-07-23

I really like that!

About This Instructable




Bio: I am an electronic artist living in Brooklyn, NY. I work with LEDs and microcontrollers to create beautiful objects.
More by ledartist:Joule Thief Filament LampT962A SMD Reflow Oven Fix/HackColor Organ Triple Deluxe II
Add instructable to: