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Topic: WS2803 versus WS2801 (Read 17850 times) previous topic - next topic

Omnimusha



hello, I can connect the other cheats, cascaded with an only resintencia?, I mean the resistance to the gnd, table chit ref

KirAsh4

Each one must have their own resistor.

Omnimusha

hello, the library WS2801 Write 24 bits per pixel (color, full color 24-bit) and the library WS2801 Write 8 bits per pixel (full color 8-bit)?

KirAsh4

No.  Both of them write the same amount.  The WS2801 needs 24 bits total: with 3 channels, that's 8 bits per CHANNEL.  The WS2803 needs 144 bits total: with 18 channels, that's 144/18 = 8 bits per CHANNEL.

Omnimusha

I refer to color, color palette, which can generate these libraries.
the library WS2801 says 24bit full color "speed PWM drivers for 24 bit color per pixe". but the WS2803?

another question, I have connected to chit WS2803 with 3.3 volts. rgb led smd and 5050, without resistance, lights and all, but when I try main SW RGB LEDs blink while this is not a constant light.
I think that no resistance, that resistance should agregarles?

Here the datashiit of LEDs

http://www.ebay.com/itm/100-pcs-New-RGB-PLCC-6-5050-3-CHIPS-SMT-SMD-LED-Light-/170786097936?pt=LH_DefaultDomain_0&hash=item27c3a50b10

KirAsh4

#35
Oct 25, 2012, 09:55 pm Last Edit: Oct 25, 2012, 09:58 pm by KirAsh4 Reason: 1

I refer to color, color palette, which can generate these libraries.
the library WS2801 says 24bit full color "speed PWM drivers for 24 bit color per pixe". but the WS2803?


Read the datasheet.  Do your own calculations like I did above.  They both provide 24 bits per pixel.  2801 only drives one RGB pixel (or group.)  2803 drives 6 RGB pixels (or groups): 6 x 24 = 144 bits, which is what the 2803 needs.


another question, I have connected to chit WS2803 with 3.3 volts. rgb led smd and 5050, without resistance, lights and all, but when I try main SW RGB LEDs blink while this is not a constant light.
I think that no resistance, that resistance should agregarles?


Again, read the datasheet.  A resistor is required to set the proper current.  You can't expect it to work properly if you don't follow the datasheet's instructions.  If you want to go at it in your own way, that's great.  It makes for fun experimenting.  However, you have to expect things to behave very different than what's expected from them.


Here the datashiit of LEDs

http://www.ebay.com/itm/100-pcs-New-RGB-PLCC-6-5050-3-CHIPS-SMT-SMD-LED-Light-/170786097936?pt=LH_DefaultDomain_0&hash=item27c3a50b10


Those are the same ones I use and they work great, both with the 2801 as well as the 2803.  The difference is, the 2803 requires 144 bits of data (8 bit per channel), whereas the 2801 only needs 24 (again, 8 bits per channel.)

Omnimusha

#36
Nov 06, 2012, 02:12 am Last Edit: Nov 06, 2012, 02:18 am by Omnimusha Reason: 1
ok, then.......





http://subefotos.com/ver/?a36a2513e7065f040792f69824e66389o.png


okay my calculations?

regards!!

KirAsh4

Calculations for what exactly?


KirAsh4

Still, I have no idea what he's calculating.  That figure has to do with the supply to the IC, not what the LEDs need for current.  The datasheet also specifically states what size resistor is needed for a 20mA current output.  So I have no idea what he's trying to calculate here.  But then, this is what happens when people don't bother to actually *read* the datasheet.

Omnimusha

I thought I had been clear,
I need to calculate the resistance for LED, LED BY THE SPECIFICATIONS AND CHIT.



YOU KirAsh4, sorry if my ingnortacia bothers you, but if I inform
I read the datasheet. heurodito'm not in the field.
If you are uncomfortable with my questions, please disregard. I will not tolerate
their lack of repect.

KirAsh4

As I said, the datasheet specifically tells you what size resistor you need for a 20mA output for driving LEDs.  The LEDs you're using (or claim you're using) are 20mA per channel.  I really have no clue what you're trying to calculate when the answer is stated very clearly in the datasheet, in other words, YOU DO NOT NEED TO BE CALCULATING ANYTHING, READ THE DATASHEET.


Hippynerd

You probably want to remove those resistors. The ICs are supposed to control the current to the LED. If you had used shift registers (like the 74hc595), then you would want resistors (Im using similar LEDs, and I used 150 ohm on the red, and 100 ohm on the blue and green.
I was having problems, until I started testing my components individually, and I found that my LEDs were doing something different than I had expected.
https://sites.google.com/site/rgbledcubes

KirAsh4

Those resistors are not needed for your application.

I also told you a few posts back that every IC needs its own resistor.  Your image still shows the reference resistor being shared.

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