Raspberry Pi Forums

Hi All,

My RPi project is driving two large LED displays, each display needing 12V/0.16A each. Digging through my PSU box, I came across a power supply for an external drive which may fit the bill.

From the PSU label:

AC Input: 100-240VAC/1.2A
DC Output: +5V/3A, +12V/3A

The PSU has a 4-pin, PS/2-like, connector: +12V, +5V and 2 'return' pins. Would this be sufficient to power my RPi and these 2 12v/0.16A LED displays? Anything else I should be aware of to make this a safe choice?

Thanks for any advice!

Yes it should work.

You will, of course, have to connect the 5v to to the Pi.
Safest would be to connect a USB socket to the 5v and ground pins, and use a standard USB cable to connect the Pi
I would be thinking of connecting to the "GPIO" connector pins. It's simpler but less safe, but then I'm lazy

In your other post, you're asking about the Sure LED displays and SPI.
I'm not sure how like full SPI the interface is, but I would ignore that claim, and just go for bit-banging three ordinary GPIOs. It won't need to be very fast, so even using Python you could drive several 595 shift registers at 10Hz refresh rate and still have time to do other things

Thanks for the reply!

The nice thing about this PCU is that I can keep the 'guts' outside the enclosure, which should reduce any heat risk. Then run just the cable into the box and split the two voltages to where they need to go.

The downside is that if the PSU ever fails, then it'll be a real pain to try and find another one with similar specs.

I posted your reply to my other note on the Sure displays for others to refer to. Thanks again.

I'd check the 5v output to make sure it's not too high. Are you sure it's well enough regulated?

Another option would be to use a car USB charger (cigarette lighter type) to convert the 12v to 5v and not use the 5v output of your supply. If your PSU fails, you'd only have to find a replacement 12v supply.

Great idea. Taking that one step further...

Just toss the hard-to-find, expensive, 12V/5V supply with the bugger-to-find Kycon connector and just use a single 12V power supply rated with enough amps. Then inside-the-enclosure run a 12V line through the cigarette lighter charger and voila, I have both a 12V and a 5V.

I have lots of room in the enclosure. I wonder how many Amps can you draw off a cigarette lighter charger?

Thanks for the help.