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[on:]

Hi all,this is my first post, I have buyed 5mt of 5050 led strip, but i realized that it was really strange no classic 4 wire RGB pin like others but these one that you could see in the photo.
There are someone that can help me? I would like to drive some of these cutted strip with arduino.
Thank in advance for your help guys

1° photo with waterproof
2° photo with scratched surface
3° photo with scratched bottom
4° photo Connector

[Reply #1 on:]

The big trace is most likely ground.  You might be able to tell what the others do by connecting 3V between Ground and one of the other pins to see what lights up.  Perhaps there are thee sets of R, G and B inputs so that chase patterns can be produced.

[Reply #2 on:]

Thanks for the reply,  I had already tried connecting the bigger one pin (grn) and trying other pins with a voltage of 3v, but nothing happened.
If I connect ground pin and then I touch resistor 2 of them give me red and green but the third doesn't give blue while if I connect ground pin and touch led pin only one of the 3 light up with red color.
Finally if I connect directly  ground of the led with 3 pin rgb of the led...all of them work fine
 
I really don't know what to do.

[Reply #3 on:]

In your second photo, The cathode of the first LED, closest to the end, appears to connect to what has been assumed to be ground.
The second LED does not appear to connect the same pin to the same track,

Could you use a multi-meter to check for connectivity between the 10 strip connections and the various pins of the LEDs that way you do not need to worry about getting things the right way round to get it to light up as confirmation of operation.

Also on your last picture, showing the actual connector for the strip I assume?
Some of the cables have markings, I can clearly see a '+' marked line and a '-' marked line, suggesting the LEDs are not simply controlled by applying a voltage to the anode, a single voltage is applied to the strip and this is somehow distributed to the anodes controlled by the other lines?

[Reply #4 on:]

Also:

http://arduino.cc/forum/index.php/topic,79839.0.html
This thread shows someone reverse engineering a digital RGB strip, it has 8 connections... though it also has IC's from controlling addressing.

The analogue strips have 4 pins, digital have more... could you link to where you got the strip from?

[Reply #5 on:]

I had already tested with a multimeter but with really poor results.

I post an image of what i have find, after your post i have rechecked and edit the image with the hope that I could reach my target 

@dean8020
Some of the cables have markings, I can clearly see a '+' marked line and a '-' marked line, suggesting the LEDs are not simply controlled by applying a voltage to the anode, a single voltage is applied to the strip and this is somehow distributed to the anodes controlled by the other lines?

you see correct! But i don't know how i hope picutre could help

[Reply #6 on:]

http://www.obr-recording.co.uk/Arduino/RGB Strip.png
 In my schematic I have labelled LED pins and Resistors so if I say Pin1 that is the pin labelled as 1 on the LED etc.
I have started piecing together your information.

From what I understand:

Connecting the large 'Gnd' Pin to ground and applying a voltage to all other pins at the end of the strip does nothing.

Connecting the large 'Gnd' pin to ground and applying a voltage to the legs of the resistors gets you green and red, is this on all 3 LEDs at once??
From what I can see in the pictures I am going to have a couple of guesses here, you will have to tell me yes or no, and correct when I am wrong.
   Connecting power to R3 (the resistor on its own) gives you green?
    Connecting power to R2 (the left resistor of the pair in your last photo, marked 331) gives you Red?

And R1 gives nothing where you expected blue?

Could you read the marking on the last resistor, I can make it out in your photos.


Could you try the following with your multi-meter if possible?

Check to see if pins 1,2,3 are connected
Check to see if pins 7,8,9 are connected
Check to see if pins 13,14,15 are connected

What voltage are you using when you do your test?

Could you try the following and let me know the result
Try putting gnd on pin 15 and power on pin 6
Try gnd on pin 14 and power on pin 5
Try gnd on pin 13 and power on pin 4

Dean

[Reply #7 on:]

Thanks Dean you have a very analytical approach to problems !!

"Connecting the large 'Gnd' Pin to ground and applying a voltage to all other pins at the end of the strip does nothing"        yes that is true
"Connecting the large 'Gnd' pin to ground and applying a voltage to the legs of the resistors gets you green and red, is this on all 3 LEDs at once??"    No light up green and red only the last led
"Connecting power to R3 (the resistor on its own) gives you green?"   NO nothing happen (only the couple of the other resistor make led light up labelled 331; 271)
"Connecting power to R2 (the left resistor of the pair in your last photo, marked 331) gives you Red?"   YESSS  331 red 271 green
"And R1 gives nothing where you expected blue?"   Well R3 gives nothing where I expected blu while R1(271) give me green
"Check to see if pins 1,2,3 are connected"   No they aren't
"Check to see if pins 7,8,9 are connected"   No they aren't
"Check to see if pins 13,14,15 are connected"  Yep  that should be ground
"What voltage are you using when you do your test?"  For my test i use a 3 volt power supply
"Try putting gnd on pin 15 and power on pin 6"  Nothing happen
"Try gnd on pin 14 and power on pin 5"  Nothing happen
"Try gnd on pin 13 and power on pin 4"  Nothing happen

BUT.........

if I put gnd on pin 4 and power on the second half E of the connector light up blu led of the first led
if I put gnd on pin 11 and power on the second half B of the connector light up red led of the first led
if I put gnd on pin 3 and power on pin D on the first half of the connector light up green led of first led

if I put power first on pin 9 then 8 then 7 ( with gnd on GROUND bigger pin of the connector) i see last led light up in green(9) red( blue(7)
if I put ground ( with gnd on GROUND bigger pin of the connector ) and power on pin 11, both second and third led light up red gentle not bright

[Reply #8 on:]

Ok,
I got a couple of assumptions wrong about which colours were which pins, I just found a generic data sheet.

I think the LEDs are connected like this:
www.obr-recording.co.uk/Arduino/RGB LED.png

To confirm this you can do the following checks:

Connections should exist between:
Pin 2 and Pin 11
Pin 8 and Pin 17
Pin 1 and Pin 10
Pin 7 and Pin 16
Pin 3 and Pin 12
Pin 9 and Pin 18

When you connect 3V to resistor 331 this lights red on the final LED, as the resistor is in the posistion shown in the picture.
When you connect 3V to resistor 271 this lights green on the final LED as it has the same configuration as the Red strip.
When you connect 3V to resistor 151 blue does not light, as this resistor is before two LEDs, and 3V is not enough for both voltage drops.  Try something more like 5 or 6V and blue should light on two LEDs.

if I put gnd on pin 4 and power on the second half E of the connector light up blu led of the first led
if I put gnd on pin 11 and power on the second half B of the connector light up red led of the first led
if I put gnd on pin 3 and power on pin D on the first half of the connector light up green led of first led

This would suggest applying:
Power to second half E controls blue on all 3 LEDs
Power to second half B controls Red on all 3 LEDs
Power to first half D controls Green on all 3 LEDs

Just 3V isn't enough to power them as the 3 LEDs are in series, 6V or more depending on the voltage drops of the colours.

Red is usually ~1.7V
Green is ~2.0V
and Blue can be up to ~3V.

if I put ground ( with gnd on GROUND bigger pin of the connector ) and power on pin 11, both second and third led light up red gentle not bright

This is because you are connecting power through 2 of the LED's in the red chain, and 3V is probably about enough to get the dim glow from 2 LEDs in series (Due to the 1.7V drop - 2x1.7V isnt too much more than 3)

My final assumption would be that the 6 remaining lines pass through this 3 LED strip and into the next strip... so the LED's down the 5m strip are controlled in groups of 3.
So 3 of the 6 unused input pins pass to the 3 colour inputs of the next strip, the next unused set of 3 shift down a set, and the current input gets shifted to the top of the pile.  I am struggling to explain this, I will try a diagram.

http://www.obr-recording.co.uk/Arduino/RGB Strip 2.png

Dean

[Reply #9 on:]

You're a genius!!!!!!! great explaining schematics you're really a master!!!

Pin 2 and Pin 11
Pin 8 and Pin 17
Pin 1 and Pin 10
Pin 7 and Pin 16
Pin 3 and Pin 12
Pin 9 and Pin 18

YES to all of them

For my test i use 9v and:



Power to second half E controls blue on 2 LEDs the second and third
Power to second half B controls Red on all 2 LEDs the first and the second
Power to first half D controls Green on all 3 LEDs yes this is true
ok so there will be a crossing one

sorry now I'm confusing, but this strip has common anode? i ask this 'cause i would like to drive some strip led with a tlc5941 and i believe that the only way to drive it is with common anode or 12v supply could damange tlc5941 no?
Dean You really help me a lot mister! i really thanksfully

[Reply #10 on:]

The fact that some of the connections on the end of the strip have the ability to turn on just 2 of the LEDs means my last assumption was probably wrong, and all the lines may be used for controlling these 3 LEDs.

It could probably be figured out with some more testing,
But what do you want to control with the Arduino?
Is it enough to be able to control RGB on all 3 at the same time (i.e. you can pick any colour but all 3 LEDs will have that colour?)
If so connecting your 9V to pins 4,5,6 should give you the colours on all 3 LEDs (can you scratch away the coating on the track going to each of those pins and solder to it?)

This small strip appears to be common cathode, (If you are going with 3 LEDs the same colour treat it as one LED for simplicity) as the last cathode in each of the 3 colours is connected.

Are you planning on splitting the whole length into these small strips?

If you want to control the entire 5m at once things will get complicated again and we will probably need to figure out the rest of the wires properly....


I haven't used that IC before, I'm sure someone here will have though,

This datasheet:
http://pdf1.alldatasheet.com/datasheet-pdf/view/117914/TI/TLC5941.html
Says the IC is specified for LED supplies of up to 17V, so it should be able to control 12V easily with no risk of damage.  The IC's own V_cc is 5V and should come from the Arduino supply.

[Reply #11 on:]

I think I see what you mean now about the tcl5941 and this strip.

The device would cope with the 12V but it's LED driver outputs connect to the cathode of the LED, so you need a common anode LED, which this strip is not.

I guess there may be a common cathode LED driver with similar functions.

Edit: something like this?
http://pdf1.alldatasheet.com/datasheet-pdf/view/137017/MARKTECH/TB62710F.html

[Reply #12 on:]

Thanks i think I will go with that TB62710F, By the way now all works fine thank of your help. Really thank a lot

[Reply #13 on:]

Glad to be of help

Let us know how the project goes

[Reply #14 on:]

Again here, sorry, i've read that someone has build a library for tlc5940 that support multiplexing so i believe that it's possible drive also common cathode like mine strip.
How could I interface with tlc5940 multiplexing it? I know that I need of a NPN transistor but I did't realized well wath i must do. Thanks again