2 Replies Latest reply on Nov 3, 2017 7:57 AM by CadSoft Guest

    How is this RGB Led strip connected

    xhendos

      Dear Element14 community,

       

      Recently I have bought this RGB LED strip. Once it arrived I have looked at the 2 datasheets of the components which it contains.

      1) WS2811datasheet which converts a serial input signal to 3 parallel output signals (red, green, blue).

      2) WS2812B datasheet which describes an individual LED.

       

      The first thing that is remarkable is that both datasheets have different timing characteristics. For example to send a 0H in the WS2811 this requires 0.5 us HIGH voltage, but the WS2812B requires 0.4 us HIGH voltage to send a 0H. How are WS2811 and the WS2812B be able to communicate with eachother?

       

      My other question is, how is the whole led strip soldered? As we can see on the website where I bought the strip, there are 3 female pins comming out of the strip. 1 is VDD and the other is VSS. The last that is left is data in. If I send data through my microcontroller to this data pin, I send data to the WS2811. Am I right?

      The WS2811 produces 3 parallel outputs (red, green, blue), but the WS2812B LED contains only 1 data in? Why is there a need for individual colors if the LED can only take 1 data in?

       

       

      I hope some experienced engineers can help me solving the question marks I have around this strip.

      Kind regards,

      Xhendos.

        • Re: How is this RGB Led strip connected
          shabaz

          I think the 2812B incorporates the 2811 integrated circuit internally along with the three LEDs. There there are thousands of tutorials on these devices. There could well be discrepancies in the data sheets, these are "hobby grade" parts. Your best bet is to examine example code and example schematics from the hundreds/thousands of tutorials. If you have a strip then if the vendor has not provided enough information, it should be straightforward to visually see the supply and data in/out connections.

          • Re: How is this RGB Led strip connected
            CadSoft Guest

            Am 03.11.2017 um 13:27 schrieb Youri Klaassens:

            Dear Element14 community,

             

            Recently I have bought this (https://nl.aliexpress.com/item/30-60-144-Pixels-Programmable-Individual-Addressable-LED-Strip-Light-WS2812B-WS2811-Built-in-5050-RGB/32812945088.html) RGB LED strip. Once it arrived I have looked at the 2 datasheets of the components which it contains.

            1) WS2811 (https://cdn-shop.adafruit.com/datasheets/WS2811.pdf)datasheet which converts a serial input signal to 3 parallel output signals (red, green, blue).

            2) WS2812B (https://cdn-shop.adafruit.com/datasheets/WS2812B.pdf) datasheet which describes an individual LED.

             

            The first thing that is remarkable is that both datasheets have different timing characteristics. For example to send a 0H in the WS2811 this requires 0.5 us HIGH voltage, but the WS2812B requires 0.4 us HIGH voltage to send a 0H. How are WS2811 and the WS2812B be able to communicate with eachother?

             

            My other question is, how is the whole led strip soldered? As we can see on the website where I bought the strip, there are 3 female pins comming out of the strip. 1 is VDD and the other is VSS. The last that is left is data in. If I send data through my microcontroller to this data pin, I send data to the WS2811. Am I right?

            The WS2811 produces 3 parallel outputs (red, green, blue), but the WS2812B LED contains only 1 data in? Why is there a need for individual colors if the LED can only take 1 data in?

             

             

            I hope some experienced engineers can help me solving the question marks I have around this strip.

            Kind regards,

            Xhendos.

             

            --

            To view any images and attachments in this post, visit:

            https://www.element14.com/community/message/230685

             

            Each of the RGB-Leds contains an WS2811 controller and its output is

            connected to the next controller (led) input. The Information of

            brightness is 8 bits for each colour thus 24 bits for 3 colours. The

            sequence is shown in the data sheet.

             

            --

            Mit freundlichen Grüßen / With best regards

             

            Joern Paschedag