Hi I have an arduino nano, a ws2813 led strip, and a 5V 10A power supply. I'm trying to make a diy ambilight for my monitor.
This being my first project and having a limited knowledge of electronics in general, I want to make sure I have everything hooked up properly.
First question: Should I power the Nano through the 5V power supply or through the usb? I'll be feeding data to the nano through the usb. Does the Nano draw power from the usb even if I power it with a external power supply?
Right now I have the (+) wire from the power supply connected to the +5V on the led strip and the (-) wire connected to the GND on the led strip and to the GND on the nano. Then I have a usb from the nano to to my PC.
Also just for reference I'm using 108 leds on the strip.
Second question: The ws2813 leds have a backup data line. I connected the DI from the led strip to the D3 input on the nano. Where should the BI lead connect to? I read somewhere that it should be connected to the GND on the nano. Is this correct?
OK, first thing is that the Nano is the correct module for this, the UNO is particularly inconvenient to use and has a problem with external 5 V powering and being connected to a PC.
So you have the necessary regulated 5 V power supply. You connect that directly to the power connections on the LED strip. You actually need to connect it to both ends of the strip and possibly the middle as well, using twin cable of at least 1 mm2 rating running along with the strip - as the foil on the strip is not in any way adequate to conduct 10 Amps.
Now, the Nano is feeding the strip (I can't answer on the "backup" data) with the data and ground (whenever we mention any connection, it is always that connection plus ground). You run the 5 V power back as a tight bundle with those wires to the Nano "5V" terminal. (Ignore "Vin, it is useless!) The diode in the Nano prevents this feeding back into the USB interface.
Note the 470 µF or 1 mF capacitor across 5V and ground and the series 330 (or 470) Ohm resistor in series with Din advised to be included at the place where the data feeds in to the strip.
Paul__B:
OK, first thing is that the Nano is the correct module for this, the UNO is particularly inconvenient to use and has a problem with external 5 V powering and being connected to a PC.
So you have the necessary regulated 5 V power supply. You connect that directly to the power connections on the LED strip. You actually need to connect it to both ends of the strip and possibly the middle as well, using twin cable of at least 1 mm2 rating running along with the strip - as the foil on the strip is not in any way adequate to conduct 10 Amps.
Now, the Nano is feeding the strip (I can't answer on the "backup" data) with the data and ground (whenever we mention any connection, it is always that connection plus ground). You run the 5 V power back as a tight bundle with those wires to the Nano "5V" terminal. (Ignore "Vin, it is useless!) The diode in the Nano prevents this feeding back into the USB interface.
Note the 470 µF or 1 mF capacitor across 5V and ground and the series 330 (or 470) Ohm resistor in series with Din advised to be included at the place where the data feeds in to the strip.
Thanks for the reply.
If the led strip I'm using is only 70" long with 108 leds, is it still necessary to power both ends?
Also just so i'm getting this, I run the +5V lead from the led strip (from both ends perhaps) into the 5V terminal on the nano and it will stop power from being drawn from the usb?
As to where power is being drawn from, if the strip connects to the Nano at all, the Nano will not be happy.
The Regulator is only rated for 150mA (so 2-3 LEDs), USB2.0 only supplies 500mA (so 7-9 LEDs), so just don't connect the LEDs to +5 on the Nano. Just connect them to their own supply.
When your system is no longer being programmer, connect the Nano to the 5V supply also.
As to where power is being drawn from, if the strip connects to the Nano at all, the Nano will not be happy.
The Regulator is only rated for 150mA (so 2-3 LEDs), USB2.0 only supplies 500mA (so 7-9 LEDs), so just don't connect the LEDs to +5 on the Nano. Just connect them to their own supply.
When your system is no longer being programmer, connect the Nano to the 5V supply also.
I believe that's the correct schematic.
However, I think I just fried my strip. I connected it to a 5V 10A power supply. Is that too much current for a 5 meter strip? Maybe I had the terminals opposite. I think I'm making myself more confused.
If you connected 5V and Gnd in reverse, that would fry the smart chip that inside each WS2813 LED.
The LEDs will only draw the current needed. If you had commanded all to full bright, each LED would draw up to 60mA, so 10A/.06A = 166, so 160+ LEDs could be powered without weird stuff happening from voltage drops down the strip.
Power is connected in multiple places so that the copper traces that carries power & Gnd does not overheat from having to carry all the current.
CrossRoads:
As to where power is being drawn from, if the strip connects to the Nano at all, the Nano will not be happy.
Not so! The Nano will be perfectly happy as long as the 5 V supply to the strip is turned on, there does not seem to be any expectation here that the LEDs would be powered from the Nano.
It will probably survive if the external supply is not turned on as long as the LEDs are not programmed on - 108 dark LEDs will draw about 100 mA which is manageable from USB.
CrossRoads:
The Regulator is only rated for 150mA (so 2-3 LEDs), USB2.0 only supplies 500mA (so 7-9 LEDs), so just don't connect the LEDs to +5 on the Nano. Just connect them to their own supply.
When your system is no longer being programmer, connect the Nano to the 5V supply also.
As I understand it, and as I explained it, voven88 is connecting the 5 V power supply directly to the LED strip. Connecting it backwards would clearly destroy the strip.
There is no problem connecting the external 5 V supply to the Nano as well as the USB, the "+5V/USB Auto selector" diode in your diagram prevents "back-feeding" into the USB port. That is just one reason the Nano is superior to the UNO.
Full white consumption of 108 LEDs - about 6 Amps. Connecting power to both ends would probably be sufficient. A 10 Amp supply should be just comfortably over-rated to run nice and cool.
