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Thread: separating VIN from VUSB for the OctoWS2811 library

  1. #1
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    separating VIN from VUSB for the OctoWS2811 library

    Hello,

    I just bought a fantastic Teensy 3.0 and I am playing along with IMUs and it works perfectly, thanks!
    Besides IMUs, i am playing with Teensy and addressable RGB LED strips, as I have 10 meters of the following leds:
    http://www.gree-leds.com/productshow...eID=Y0YY52S0YX

    If my calculus is correct (0.25watt per LED, 70 leds per meter, 10 meter) i have to provide 175 Watt.

    Given that is correct, i have to suppy that energy to the leds.

    My questions are:
    Can i just supply energy to the Teensy by the usb cable (the usual .5A), and supply energy to the led strip (175Watt)by an external (stabilized) power supplier?
    Or do i really need to separate the VIN from the VUSB on the Teensy board? If i am correct, this means also that the Teensy is not powered anymore by the usb cable, but only data will pass on the usb cable.
    If I reallly need to separate the VIN from the VUSB, well, my question is: how to do it? I have not seen any picture of a Teensy board where the VIN and the VUSB are cut apart. This procedure is briefly explained here: http://www.pjrc.com/teensy/td_libs_OctoWS2811.html

    Thanks a lot for you support,
    Luke

  2. #2
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by mercyful View Post
    My questions are:
    Can i just supply energy to the Teensy by the usb cable (the usual .5A), and supply energy to the led strip (175Watt)by an external (stabilized) power supplier?
    Yes. Of course, the grounds from the 2 power sources need to be compatible.


    Or do i really need to separate the VIN from the VUSB on the Teensy board? If i am correct, this means also that the Teensy is not powered anymore by the usb cable, but only data will pass on the usb cable.
    That's another option. Either way is fine. But if you connect VIN to your non-USB power, you really must cut that jumper so the power doesn't conflict with the power from the USB cable.


    I have not seen any picture of a Teensy board where the VIN and the VUSB are cut apart. This procedure is briefly explained here: http://www.pjrc.com/teensy/td_libs_OctoWS2811.html
    My test 1920 LEDs... the ones show in the photos and video on the OctoWS2811, have those jumpers cut on the Teensy 3.0s. I didn't take a photo of the back side of the boards, but if you look closely, you can clearly see they are wired to the power lines coming from the 3 big power supplies on the back side.

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