A different kind of fireworks controller

[jrock64]

Nothing new or dangerous here.
I just want to have control of 41 LEDs so I can fire them in a pattern that looks something like this. Imagine this at the top of an eight channel fire stick
http://home.mchsi.com/%7Ejrock642/xmas1/Fire-Works.gif
If not animated click here http://home.mchsi.com/~jrock642/xmas1/Fire-Works.gif (http://home.mchsi.com/%7Ejrock642/xmas1/Fire-Works.gif)
8 channels would work but 16 channels would be even better.
At first I thought of attaching ULN2803's to my 80 channel Renard but by the time I got all that cobbled together I may as well start from scratch.

Now I have decided on an 8 or 16 channel controller hardwired to the firework wire frame. Something like a 16 channel super pixel without the LEDs.

I think JECs pixel design can be expanded to 8 channels but is it a simple as adding another PIC to get 16 channels?

I know Phil has something in the works for low voltage control. No real details yet.

I know Mr Packethead has the modular Christmas Card design out there out there and I have seen parts but don't really understand the big picture on that project yet.

Several others have thrown this out in other threads and were fishing for information with no specific answers.
This is my specific application. I don't know if it could be used others by others or not, but it will make my July 4 show spectacular if I can make this happen.

Joel

[Wombat]

just use an olsen 595 or similar board to drive the LED's off the outputs of the ULN2803's on an olsen. I do a similar thing to the olsen but run all my 2803's off 24V then you can string up to 10 LED's in series and a resistor to limit the current for each of your display outputs.

fairly easy design to achieve.

Wombat

[acewingman]

Can't you use the LEDTrik for this? While playing around with the plugin in Vixen I did something similiar to this...

[JEC]

Nothing new or dangerous here.
I just want to have control of 41 LEDs so I can fire them in a pattern that looks something like this. Imagine this at the top of an eight channel fire stick
http://home.mchsi.com/%7Ejrock642/xmas1/Fire-Works.gif
If not animated click here http://home.mchsi.com/~jrock642/xmas1/Fire-Works.gif (http://home.mchsi.com/%7Ejrock642/xmas1/Fire-Works.gif)
8 channels would work but 16 channels would be even better.
At first I thought of attaching ULN2803's to my 80 channel Renard but by the time I got all that cobbled together I may as well start from scratch.

Now I have decided on an 8 or 16 channel controller hardwired to the firework wire frame. Something like a 16 channel super pixel without the LEDs.

I think JECs pixel design can be expanded to 8 channels but is it a simple as adding another PIC to get 16 channels?

I know Phil has something in the works for low voltage control. No real details yet.

I know Mr Packethead has the modular Christmas Card design out there out there and I have seen parts but don't really understand the big picture on that project yet.

Several others have thrown this out in other threads and were fishing for information with no specific answers.
This is my specific application. I don't know if it could be used others by others or not, but it will make my July 4 show spectacular if I can make this happen.

Joel


The pixel design could be expanded to nearly as many free channels as there are on the PIC (less power, ground and data input).

A 16F876 ($5, 28 pins) could drive 20+ channels easily.

[JEC]

Nothing new or dangerous here.
I just want to have control of 41 LEDs so I can fire them in a pattern that looks something like this. Imagine this at the top of an eight channel fire stick
http://home.mchsi.com/%7Ejrock642/xmas1/Fire-Works.gif
If not animated click here http://home.mchsi.com/~jrock642/xmas1/Fire-Works.gif (http://home.mchsi.com/%7Ejrock642/xmas1/Fire-Works.gif)
8 channels would work but 16 channels would be even better.
At first I thought of attaching ULN2803's to my 80 channel Renard but by the time I got all that cobbled together I may as well start from scratch.

Now I have decided on an 8 or 16 channel controller hardwired to the firework wire frame. Something like a 16 channel super pixel without the LEDs.

I think JECs pixel design can be expanded to 8 channels but is it a simple as adding another PIC to get 16 channels?

I know Phil has something in the works for low voltage control. No real details yet.

I know Mr Packethead has the modular Christmas Card design out there out there and I have seen parts but don't really understand the big picture on that project yet.

Several others have thrown this out in other threads and were fishing for information with no specific answers.
This is my specific application. I don't know if it could be used others by others or not, but it will make my July 4 show spectacular if I can make this happen.

Joel


The pixel design could be expanded to nearly as many free channels as there are on the PIC (less power, ground and data input).

A 16F876 ($5, 28 pins) could drive 20+ channels easily.

[jrock64]

Thanks JEC.
Thats exactly the answer I was looking for.
That larger PIC opens some interesting possibilities.

From deciphering the pixel schematic it appears that you drive the string of three LEDs at 20ma.
Does this mean that each individual LED is only driven at 7ma?

I thought that LEDs were driven at 10 to 15ma each.
Or am I misunderstanding something because they are connected in series?

JOel

[JEC]

Thanks JEC.

From deciphering the pixel schematic it appears that you drive the string of three LEDs at 20ma.
Does this mean that each individual LED is only driven at 7ma?

I thought that LEDs were driven at 10 to 15ma each.
Or am I misunderstanding something because they are connected in series?

JOel

Nope. Since they're in series, the current is the same through each LED.

Remember Ohm's Law: V= IR

Or, I = V/R
Or, R = V/I

Here's the math:

(Vsupply - Vled - Vce transistor) / R = Drive Current

So the regular pixels have two chains of LEDs per color, times three colors.

20 mA per chain, 40 mA per color, 120 mA per pixel

Drive current is based on the specifications of the particular device you're using. Generally 10 mA will light anything up, but since we're going for maximum (safe) intensity, we check the specific datasheet and see what the highest constant current can be.

Some LEDs max out at 20 mA. Some are happy at 50 mA. The Luxeon clones that misterpackethead has been using run most efficiently at 350, 700 or sometimes 1000 mA, depending on the device.

[yosoniamcool3]

what about some think like this i made it 2 year ago hear is a video of it
http://www.youtube.com/watch?v=rgYtcfAHSjs&NR=1 or
http://www.youtube.com/watch?v=hx1vZZ71QuI
it has 16 channel and is 10 feet wide and tall
if u want more on it tell me i got lots on it hand made

[P. Short]

Are you looking for dimming those 41 LEDs, or just simple on/off? And do all 41 LEDs need independent control, or are you planning on always having 4 LEDs having the same state?

--

Phil

[jrock64]

Dimming would be nice but not absolutely necessary for this specific application. The entire sequence will last less than one second so dimming would not be noticeable.

I'll admit it. Individual control would be overkill but I can see some nice possibilities with 14 or 18 channels.

1 channel with 5 yellow
1 channels with 4 orange
2 channels with 4 red
2 channels with 4 green
4 channels with 2 blue
4 channels with 2 white

additional channels would break the red and green into sets of 2

Thank for looking.
JOel

[P. Short]

I'd go with the last solution the JEC mentioned if you are willing to do it from scratch with a PIC.

--

Phil

[jrock64]

Been going over the Microchip site for hours... maybe days.
The PIC16F913 seems to have all the same features as the PIC16F688 just 24 available IO pins instead of 11.
Should be able to get at least 19 channels to control LEDs
Since it is the same PIC16 family I am going to assume JECs code would drop in by just remapping the IO ports and adding all the extra channels.
2.21 at quantity 25. Less than two PIC16F688's

Am I headed in the right direction for what I want to do with this project or am I lost in blizzard and blinded by the blinking lights.

JOel