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Norfolk UK
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I'm going to cut up almost the whole strip to use them seperatly.
Something like:
Arduino Leonardo -> IC -> 3 or 6 Led strips
Do I still need 3 NPN transistors per strip? Or can these be placed before the IC?
If your using something like the WS2803D it's datasheet says it can handle 12V directly so no need for the NPN's
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Montreal
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Which IC would fit best in here? I was thinking of the WS2803D because it's cheaper than the WS2801.
Or would you recommend somethint like the 74HC595?
WS2803D looks O'K, WS2801 is 5V you can't use it with 12V strip.
 How you need to control your 6 pieces of lighting, individually or they all changing color as a whole?
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NL
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I want to control each strip individually.
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Montreal
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O'K, than. Leonardo, AFAIK has 7 PWM pins, but you 'd need 3 x 3 = 9  /* for 3 strips */, and 3 x 6 = 18 /* for 6 strips */.
It's mean you need more PWM pins than board has. There are an options:
 WS2803 = 18 channels (1 IC needed)
 TLC5940 = 16 channels (2 IC = 32 channels)
 74HC595+ULN2803 (pair) = 8  ( 3 pairs of IC = 24 channels ).
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NL
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Oke, but is it also possible to do something like this?

Arduino
-> Supplies signal to WS2803 via PWM pin and 12V

WS2803
-> 6 led strips all on different channels
-> signal to next WS2803

I need to be sure about the 12V smiley.
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Montreal
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I find a link to data sheet at this address: http://www.world-semi.com/en/Driver/Lighting_LED_driver_chip/WS2803/
Rar archive at the bottom of page.
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Norfolk UK
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You will need a separate 12V supply that can also be used to power the arduino if needed for stand alone (no PC) operation.

Using the WS2803 chip (or chips) you don't use PWM to talk to them but a form of serial using 2 digital pins. These 2 pins will talk to all the WS2803 chips (not 2 pins per chip) as there control pins are daisy chained together CKI > CKO & SDI > SDO
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t and I'm going for a 12V 5M 300 RGB SMD 5050 led strip, with a 12V 2A power adapter.
Well, if you go with 5 meters, than look for 12V 3A switching PSU:
- 3A max current for this size of led strip;
- you need regulated PSU, wallwart or whatever cheap (transformer) type PSU usually outputs anything in between 12 - 18 and could damage leds;
- arduino could be powered from the same PSU via V-in pin.   
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NL
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I'm not going to control the whole strip at once, so I think 2A will be enough smiley.

I can't seem to find anything about about the high voltage option of the WS2803.
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Norfolk UK
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Hi Danton,

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I can't seem to find anything about about the high voltage option of the WS2803.
The WS2803 needs a 3.3 to 5.5 volt supply to power its logic but the datasheet (attached) says the output pins (connected to the LED strip) can handle -0.3 to 40 volts so 12V should be fine.

* WS2803.pdf (498.59 KB - downloaded 15 times.)
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NL
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I think I'm getting it, it's always a bit annoying when I don't understand it smiley-razz.

Something like this?

ArduinoWS280312V Led strip
5VVCC
GNDGND
2CK1
3SD1
Vin12V+
Out1Red
Out2Green
Out3Blue
« Last Edit: June 24, 2012, 04:46:31 pm by Danton » Logged

Norfolk UK
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Hi Danton,

I knocked up a rough schematic of what you need. It is by no means complete (I'm meant to be working at the moment). You will need to ground the 12V supply with the arduino ground, calculate the IREF resistor value and add a couple of caps to smooth things out. You could also power the arduino from the 12V supply either by adding a 5V voltage regulator connected to Vin on the arduino OR fit a suitable plug to connect to the arduino power socket.

* RGB_Control.pdf (18.2 KB - downloaded 41 times.)
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NL
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Hi Danton,

I knocked up a rough schematic of what you need. It is by no means complete (I'm meant to be working at the moment). You will need to ground the 12V supply with the arduino ground, calculate the IREF resistor value and add a couple of caps to smooth things out. You could also power the arduino from the 12V supply either by adding a 5V voltage regulator connected to Vin on the arduino OR fit a suitable plug to connect to the arduino power socket.

Thanks, I'm glad there are people that can help me with this.

Again a few questions:
1. Does the 5V output always need to be connected with the digital pin?
2. The resistor on IREF determines the output in mA on the output? And does the GND also need to be connected to the Arduino?
3. Where will the capacitators go and what is there exact function (type)?

This is one of my first projects and I am familiar with most parts but not really about there function and position.
I'm reading a lot of info on the internet, and I just found some tutorials I'm going to read when I have the time.
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Norfolk UK
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The VCC pin on the WS2803 needs connecting to the +5V pin on the UNO and the GND pin needs connecting to the GND pin on the UNO and to the 12V ground. The CKI and SDI pins need connecting to a couple of the UNO's digital pins as these program the WS2803 chip(s).
The IREF needs connecting to the shared ground (preferably not ground through the UNO as I'm not sure of IREF output level)
A couple of capacitors to just reduce potential electrical noise and smooth out loads. I would try one 16V 10uF electrolytic and one 16V 100nF ceramic per WS2803 connected between VCC & ground close to the WS2803

I will hopefully get to refine the drawing tomorrow.

EDIT:
Modified.

* RGB_Clock01.pdf (19.29 KB - downloaded 32 times.)
« Last Edit: June 26, 2012, 06:35:39 am by Riva » Logged


NL
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Still waiting for some of the parts.

Recieved the following:
- 12V 2A power adapter
- PCB Breadboard with jumpwire
- 10pcs WS2803D
- Electrolytic Capacitors 10uF 16V

Hope to receive the rest next week.
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