Power converter board?

[RudeViper]

Hello guys and gals,

I hope I am posting in the right forum.

Here is my project idea.

I'm going to setup my raspberry pi (1st one - I am getting another one soon to use for other things) as a media center, But I don't want half a dozen cords floating around that need to be plugged in. So to that end I have an HP printer power supply that I can use. It's a 32 volt output @ 2500 ma. I want to convert it to the following:

2 - 5v 2amp circuits
1 - 12v 2 amp circuit

The two 5 volt circuits will power the pi and the 4 port usb hub I have (cyberpower CP-H420P) and the 12 volt will be used for some old ide hard drives I have to store and transfer files to and from other sources.

That is the problem for me - I need to build a circuit board to reduce these voltages but don't really know what parts I need to make it safe and stable for me. Also - this entire set up will be put into a wood box at somepoint with the heat sinks for all three chips on pi and some fans to keep it all cool...But the biggest thing right now is to figure out the power conversion board. So I need help.

[RudeViper]

Ok a little more than a month has gone by since I posted this. I guess it either got lost in the shuffle or nobody has an answer.

Can someone at least point me in the right direction?

[ryanjennings]

I am not expert on this stuff, but this might be close.

http://www.digikey.com/product-highligh ... ators/1177

edit:
Or the LM7805. I think those just burn the extra voltage to heat though so that might not the best.

[scruss]

Do you have to use the 32V supply? There are many DC to 5V converters, but most I've seen don't go above 24V.

An old/cheap PC power supply would have all the power and cooling you'd need, along with Molex plugs for the HD power. The PC power supply will already have the 5V you need, and there are Molex to USB converters available.

[owencook]

Have a look at the MagPi, Issue 6, http://www.themagpi.com/

Page 8 has a easily constructed 5 volt regulator, and change that 2576-5 to a 2576-12 and that should do for your 12 volts.

My measurements suggest the 5 volt regulator is 80% efficient and at two amps gets pretty hot. I put a heat sink on the regulator package.

My regulator,

switchmode-1.jpg (52.69 KiB) Viewed 1368 times

[chrisbeech87]

What about something like these two(hope the links work im on mobile).

http://item.mobileweb.ebay.co.uk/viewit ... 4502498528

And

http://item.mobileweb.ebay.co.uk/viewit ... 7738728708

The first converter could power the second. I'm not sure how reliable these are though?