Hi all!
I have my RPi running in combination with a 5V LED string (ambilight-clone).
So, currently I have two power supplies hooked up, one for the Pi and another one for the LED string as it doesn't provide enough power to also power the LEDs.
I am looking for a nice 'ATX-like' soft switch, such as the ATXRaspi. However, I read in the docs that it doesn't play well in combination with additional power supplies.
Attached a diagram to display the way I have currently connected it.
(taken from: http://boblight.googlecode.com/svn/wiki/diagram.png).
I wonder if I can use ATXRaspi to perhaps even replace the second supply, or use it instead of the regular uUSB supply.
Or perhaps I simply detach the LED power supply from the GPIO?
best,
Stu.
How much power do you need for the LED strip?
The LED strip is powered by a 5V 3A supply.
To be exact: http://www.conrad.nl/ce/nl/product/512693/Stekkernetvoeding-HN-POWER-HNP18-050-5VDC-3A
Yeah that's more than the ATXRaspi spec. It was designed to power your Pi and some extra light loads.
An extra 3A is a huge demand compared to the Pi's rated 700mA.
Yeah, I thought so. So that rules out powering the whole rig with one supply. Ok, I can live with two, but..
But mostly I'm wondering if somehow I'll fry or otherwise stress the ATXRaspi when I also connect the +5V-3A to the +5V and GND GPIO pins (2 and 6). I ask because I am reading that the board doesn't work well with additional power supplies. Can I still hook it up as displayed in my diagram without causing black smoke?
I'm referring to this big warning notice:
! MORE IMPORTANT ! Make sure you DO NOT plug in power to the RaspberryPi directly/separately while ATXRaspi is connected. This might cause damage to any of the boards involved.
You could protect the ATXRaspi with a shottky diode. However I cannot endorse that. If you connect a separate supply in parallel, wouldn't that automatically power the Pi?
How about using a Pi GPIO pin to drive the power to the strip through a power FET or transistor? I think that makes more sense in your situation.