Calling all DIY LED "Junkies" - Your opinions wanted!

[O2surplus]

Originally Posted by d3snoopy

I'm saying that I think the approach that most of the servo control guys take is simply to do something like:

Set N = 1.5ms (servos typically receive signals in the 1-2ms range @ ~60Hz)

Loop:
Output a N ms pulse
Delay 18 ms
goto loop


So, if you adapted it to your purposes, you could do something like:

Set DutyCycle = 0.2

Loop:
Output a (DutyCycle * 7) ms pulse
Delay for [(1 - DutyCycle) * 7] ms
goto loop

Obviously, you'd have to account for everything else you wanted the controller to be doing... but with low PWM's everything happens slowly enough that you can just manually program the pulse widths and delays.


I don't know much about Aurdino, so I'm not sure how tricky it will be to get all of the multitasking right... especially when you want to be able to vary all the way from 0 to 100% duty cycle. with servo control, you can count on having at least 18ms between pulses... with a fully variable duty cycle you have to adjust where you get your extra clock cycles depending upon the desired duty cycle.

This driver has a clock on board and other components that can be adversely affected by altering the base PWM frequency, So I plan to just live with the default PWM settings and avoid unwanted timing "issues" that could affect reliable operation of the drivers.
The Arduino PWM outputs use 255 steps to range from 0 to 100% duty cycle across all 6 PWM output pins. That's plenty of dimming range, considering that my personal build employs 15 CAT4101's and 90 leds. I'll simply program the drivers to dim the leds in groups of six, using a time staggered arrangement. That dimming approach should make the led dimming appear perfectly natural when viewed. I may even leave 18 leds running at 1/2% duty cycle as "Moon Lightts". I'm no Arduino expert either, but I'm sure there are people out there that could make this driver design do really neat things.

[O2surplus]

Got an Email notification today telling me to expect a visit from "the Man in the Brown Van" sometime tomorrow. I guess I'll be doing some soldering tomorrow night and doing some tests, with pictures to follow.

[theblondskeleton]

[O2surplus]

The PCB's arrived from China today, so I took the time to solder one up tonight. First Impression- This is gonna be cool! I loaded the ATMEGA chip with the standard arduino "Blink" sketch just to make sure it works. All systems go! There's a red led tied in to digital pin 13, so verifying proper operation is as simple as watching for the "blink". I'll test out the actual driver section of the board sometime this weekend and post some pictures. Here's a photo of the finished driver, I paid a bit extra for "white" and I think it looks pretty clean. Let me know what you guys think.







Running the "BLINK SKETCH"

[jcgd]

Looks good. I want one.

So what can this do? Six drivers, six channels? But you need to get the controller coded right?

Are you putting an LED screen with buttons and the menus on it?

I noticed the green and red led labels are swapped. :P

[theblondskeleton]

Very nice a screen with menu and buttons would be great - easier to program for some!

[O2surplus]

Originally Posted by jcgd

Looks good. I want one.
Thanks for the compliment- I'll send you one ( U.S. Customs doesn't scare me. It's only Canada for Pete's sake, not N. Korea.)


So what can this do? Six drivers, six channels? But you need to get the controller coded right?
I didn't want to design myself "into a corner", so- think of this as an Arduino UNO w/ a DS1307 RTC(with battery back-up) married to a 6 channel,150 watt led driver. All the pins, including an I2C connection are there. You can code this to operate however you like, and use jumper wires to make connections to additional components. I already have a 6 channel code written that includes independent start/stop times, fade duration, max intensity ect.. for all 6 channels. I'll use that code with mine for the time being. Other users may want to add increased functionality by adding an LCD, temp sensors, and control buttons ect... That's totally doable.

Are you putting an LED screen with buttons and the menus on it?

I didn't want to include those items in the actual PCB since they would raise the cost, add complexity, and make replacement difficult- in the event of a component failure on the PCB. "All in one" designs are great.....until some small part or sub-assembly "lets the smoke out" and your forced to scrap the entire PCB.

I noticed the green and red led labels are swapped.

Yeah- I swapped them since "green" normally indicates "good" or "go" and the opposite for "red". I already corrected the sikscreen layer to reflect the change.

:P

...

[O2surplus]

Originally Posted by theblondskeleton

Very nice a screen with menu and buttons would be great - easier to program for some!

Hey- Thanks, You'll get one too!

I'm going to treat this design as a prototype, so I'll make changes to the design as we go. I'm open to whatever you guys want. I suppose, after we've had a chance to nail down some software, I could design a type of LCD and button "shield" that would plug in to the PCB to provide additional functionality. This will be a work in progress, but I'll have to stay as close to the original design, in order to retain "backward" compatibility.

[Pickled_Herring]

Wow O2 looks great! Pretty quick turn around too. It took me a month to get my Cat3 boards from itead. I would be interested in a board and would be willing to trade a few of these:

[O2surplus]

Originally Posted by Pickled_Herring

Wow O2 looks great! Pretty quick turn around too. It took me a month to get my Cat3 boards from itead. I would be interested in a board and would be willing to trade a few of these:

Hey Thanks! LOL I nearly paid as much for shipping as the actual cost of the PCBs! But hey- I'm not patient, 10 days was pushing it for me! I got 10 boards for $25 + $10 for full E-Testing, + $10 for "white" + another $42 and change for express UPS shipping. That breaks down to about $8.70 per board, but who cares- It's just a cost of the hobby, right?

Assuming I can build all 10 to perfection, keep 3 for myself and send out 2 to the guys inline ahead of you, that leaves 5. So one will have your name on it.

Is that a 20x4 LCD with a serial connection? We could put those to use with this project, if they are. I'm sure that I've seen some good dimming code out there that would work great with an I2C enabled LCD. I'll have to hunt it down, as that's the direction I think we should be moving.

[Pickled_Herring]

5 x 7- dot 16-character 2-line dot-matrix LCD panel. I have some better ones I'll have to see if I can get a pin-out of them.

[ReluctantHippy]

Another amazing thread. Bravo. Out of curiosity and if you don't mind me asking, about how much is the total cost to produce one finished board?

[theblondskeleton]

Originally Posted by O2surplus

Hey- Thanks, You'll get one too!

I'm going to treat this design as a prototype, so I'll make changes to the design as we go. I'm open to whatever you guys want. I suppose, after we've had a chance to nail down some software, I could design a type of LCD and button "shield" that would plug in to the PCB to provide additional functionality. This will be a work in progress, but I'll have to stay as close to the original design, in order to retain "backward" compatibility.

Groovy man What are you using for a power supply, by the way? Anything special or just a wall wart?

[jcgd]

Sweet, that's awesome, Aaron.

I've been using Meanwell 24v power supplies. Normally they are expensive but I bought a bunch online from evilbay. The guy had limited stock do I got extras but there are lots of Chinese ripoffs on there too that would probably work okay.

[O2surplus]

Originally Posted by ReluctantHippy

Another amazing thread. Bravo. Out of curiosity and if you don't mind me asking, about how much is the total cost to produce one finished board?

Good question! I'm populating a spreadsheet with component costs as time permits. I should have an exact cost nailed down in the next few days.