I am in the process of building myself a fancy schmancy Raspberry Pi "laptop", and am trying to power it with a single cord/power supply. My strategy is to put together a small project box with 120VAC inputs, and the innards from a couple wall warts to provide 5VDC and 12VDC power. Before I start wiring crap together, I wanted to run my idea past some more experienced electri-gurus to make sure I'm not missing anything safety-wise. It seems like its the perfect solution in my mind, but want to make sure I'm not missing anything that I'd be expected to know if I wasn't self-taught.
- I have an old laptop power supply that I've gutted. It's basically the cord and an empty plastic shell (2" x 3" x 5"-ish) with the male end for the plug, and the wires that were clipped from the PCB from the male cord receptacle.
- I've gutted 12VDC/2A and 5VDC/10A wall warts; I'm left with PCBs that have wires leading to the board, and barrel connectors coming off the board.
If I connect the three hots, the three neutrals and the three grounds from the PCB and power supply inputs, this will leave me with 120VAC feeding the box and getting shared by 2 PCBs that, upon testing SHOULD be putting out 12VDC, 2A and 5VDC, 10A.
Am I thinking about that right? In my mind, it's like I've got two wall warts in a power strip, minus the power strip.
Here's my power needs:
- The Raspberry Pi: 5V, 700-1000mA
- A powered USB hub: 5V, 1A (based on the 5V, 1000mA PS that came with it)
- A powered USB WiFi interface: 5V, .5A ('cause it's USB...amperage is a TOTAL guess based on no information whatsoever).
- A portable USB keyboard: 5V, .5A ('cause it's USB...amperage is a TOTAL guess based on no information whatsoever).
- A 4" LCD monitor, 12V, 0.53W (which, by my math is way under 2A).
The 12VDC barrel fits the 12V monitor, so that's set. The 5VDC output needs to have the barrel connector replaced, and as long as I'n stripping wires, I'll be adding 3 USB ports to the power supply for device charging, and plan to split the 5VDC output between the individual USBs and the cable that will supply power to the hub--the hub will supply power to all the Raspberry Pi devices, 3A. With 10A supplied, those 3 extra charging ports won't be an issue unless my phone decides to draw 7A+ for charging. Am I good with that concept as well?
Please let me know if I'm missing any fundamental safety concepts for putting this thing together, and if appropriate, an appropriate link for where I can research & read about these concepts.