Ask Slashdot: Affordable Hardware For Remote-Booting USB Devices?

phlawed writes: USB ports are everywhere. It is very convenient for powering low-power devices, and by using a run-of-the-mill phone charger you can easily get 10+ watts or so. In other words: everyone already has the generic power supply and power cable. No issue with voltage or polarity. Perfect for the hobbyist market.

Another ubiquitous power source (in the enterprise environment) is Power over Ethernet. Active PoE splitters for 12V output are available for ~6-7 USD and up on eBay. With PoE you get networking and power over the same wires, and booting your (possibly borked) PoE device is a matter of instructing the PoE source to cycle the power on that port. (Also, USB chargers with 12V input are available for less than 1 USD on eBay. They are likely all crap, though.)

I am looking for the combination of these two concepts in a compact, affordable, quality product. I found one product offering USB power from PoE. That product appears to have left out Ethernet and has a MSRP of 30 USD. Otherwise, I find PoE wall sockets for a MSRP of USD 100 or more. It appears excessive, given the cost figures of the pieces listed above.

So, if it does not already exist... anyone feel like running with this on your favorite crowdsourcing platform? Any experienced electronics people who can do a back-of-the-envelope calculation for cost of parts and assembly?

Comments

What do you mean "left out internet"?

[drinkypoo]

If you use the cheapest-possible PoE injector/splitters, which are just over a dollar, they give you a barrel jack out the side. Then you just plug your cables in. So all you need is a way to get that barrel jack out to your 5V power supply, and an appropriately high-voltage wall wart to feed it power over the PoE wires. You're overcomplicating this problem. Do not use 12V, though, if you can avoid it. Use something higher, like 17V. 17VDC wall warts and bricks are readily available, and virtually all of the cheap 5V supplies that are even vaguely wide input will run on 8-18V or so. You'll have to do the math. Actual by-the-specs PoE runs 24V so that there will be something useful at the other end. Looks like if you really scrap the bottom of the barrel you can get 5V@2A for $1 (2-24V input) but I'd go ahead and spend as much as $3 or $4 and get something which claims to do 5A if I wanted 2A. I use a lot of these cheapass eBay power supplies and whatnot and they are cheap enough to just overspecify them grossly, unless space is a serious consideration. Then you might start looking at what chips they are using and reading datasheets.

You're looking at $10 all in between a wall wart, two injector/splitters, a barrel connector, and a 2-24V to USB connector boost/buck converter. If you're really crafty, you might get that into the splitter.

Dear Timothy...

[Anonymous Coward]

How the hell did this rambling incoherent question get posted to the FRONT PAGE of Slashdot?

Re:what the hell do you want?

[JustAnotherOldGuy]

Bingo. Honestly, I read the post 5 times and I'm still unsure.

I *think* he wants a USB widget that attaches to an ethernet line and plugs into a PC so he can reboot it, but hell if I know.

Why can't people just say, "I need a thingy that does (whatever thingy is supposed to do)" and be done with it?