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King Song KS 18A USB 5V output


Raptor
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Does anyone know where in the KS 18A (on top of control module ) the PCB, USB output ( I need 5V, for LED strip ) . Because I found a 5V LED strip ( http://www.banggood.com/Waterproof-5050-USB-Black-TV-PC-Background-RGB-LED-Strip-Light-Xmas-Decor-Remote-DC5V-p-1094959.html?rmmds=myorder ) I want to make lighting for the pedals, since I don't see in the dark time of the year in which the pedals :D . But also do not want unsightly wires outside the wheel body !  whether in the photos to see the USB output wires ? 

https://goo.gl/photos/FD8nBgMSAf98K66Y7

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I can't tell from the picture, but the obvious way to find out would be to follow the wires from the USB-port:

patillaje-conector-usb.jpg

The ones you want are the VCC and GND -pins. BUT, you want to make damned sure that the USB-output of the board can give out enough current for the led-strip without burning, otherwise in the worst case you might end up with a dead mainboard.  An RGB-led strip with 5V voltage would mean that there's only a single RGB-led in series (as for example the blue-one needs around 3.2V or thereabouts, so 5V can only power a single one in series), meaning that all the leds in the strip are in parallel with each other. Also, typically the maximum current per single color led is 20mA. There are 3 different colored leds per single housing in an RGB-led, so that also means that for each housed RGB-led, the current draw can be up to 60mA at full brightness and white color. A full meter with 60 RGB-leds in parallel could thus draw up to 60 * 60mA = 3600mA or 3.6 amps! I doubt the USB-port was designed to give out that much current, but could be wrong.

As for knowing how much current the USB-output of the board can supply, it isn't exactly easy, unless it's stated in the manual. If it isn't, estimating it could be theoretically done by reverse-engineering the circuit feeding the +5V line, but that's not easy, and if it includes switching buck-converters, we're way over my league (unless it's a single chip with datasheet available, then maybe ;)). Even if it is printed on the manual, remembering that the Chinese manufacturers aren't exactly conservative with their specs (ie. they usually exaggerate rather than understate them), I'd say cut it around 50% to be on the safe side :P

Personally, I'd avoid drawing any power above a few tens of milliamps from anywhere on the board, and instead either use the batteries directly or a separate power source. But that's just me being (overly? ;)) cautious.

Edited by esaj
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  • 4 weeks later...
On 11.12.2016 at 3:27 AM, esaj said:

I can't tell from the picture, but the obvious way to find out would be to follow the wires from the USB-port:

patillaje-conector-usb.jpg

The ones you want are the VCC and GND -pins. BUT, you want to make damned sure that the USB-output of the board can give out enough current for the led-strip without burning, otherwise in the worst case you might end up with a dead mainboard.  An RGB-led strip with 5V voltage would mean that there's only a single RGB-led in series (as for example the blue-one needs around 3.2V or thereabouts, so 5V can only power a single one in series), meaning that all the leds in the strip are in parallel with each other. Also, typically the maximum current per single color led is 20mA. There are 3 different colored leds per single housing in an RGB-led, so that also means that for each housed RGB-led, the current draw can be up to 60mA at full brightness and white color. A full meter with 60 RGB-leds in parallel could thus draw up to 60 * 60mA = 3600mA or 3.6 amps! I doubt the USB-port was designed to give out that much current, but could be wrong.

As for knowing how much current the USB-output of the board can supply, it isn't exactly easy, unless it's stated in the manual. If it isn't, estimating it could be theoretically done by reverse-engineering the circuit feeding the +5V line, but that's not easy, and if it includes switching buck-converters, we're way over my league (unless it's a single chip with datasheet available, then maybe ;)). Even if it is printed on the manual, remembering that the Chinese manufacturers aren't exactly conservative with their specs (ie. they usually exaggerate rather than understate them), I'd say cut it around 50% to be on the safe side :P

Personally, I'd avoid drawing any power above a few tens of milliamps from anywhere on the board, and instead either use the batteries directly or a separate power source. But that's just me being (overly? ;)) cautious.

Thank you for the answer and I apologize for that not earlier see .

Although I really only need some help to locate the system board USB output. Only the precise location of in the board .  Led strip for lighting I will not use anyway more than only six section .Permissible for charging of the phone, is likely to be much higher load.

In any case, thank you for the warning !

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Does anyone know the exact location where to output USB power  circuit, in this motherboard ? Only location !

But the obvious way to find out would be to follow the wiring USB port but does not want  for this, the body to fully open .

Please, maybe someone knows ?

Edited by Raptor
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