UPDATE: Raspberry Pi Power over Ethernet HAT - Campaign started

[ojousima]

Hi all,

We at ELL-i Open Source Co-operative are making a Power over Ethernet HAT for Raspberry Pi Models B+ and 2B. The HAT is very simple, it takes power from PoE-enabled switch and passes data through transformer and another Ethernet jack to Raspberry Pi's own PHY. No software setup is needed, just plug the board in, connect the cables and you're ready to go. Our board has long pin header so other HATs can be attached on top, so far we have tested it with HiFiBerry DAC+ which worked fine.


Our first prototypes had some rough edges, next revision of boards is currently in mail. The schematic of design is attached, we'll open source the whole design after the launch of product.

We're launching crowdfunding campaign in late May, one board is going to cost approximately 40 euros + taxes & shipping for early birds . You can follow our progress at our blog http://ell-i.org/blog/. If you're interested in getting one board right away, you're in luck! We'll send some bare boards and parts with no markup for people willing to test out the design and give us some feedback. If you're willing to give it a try contact us at indie@ell-i.org and we'll arrange things from there.

EDIT: Thank you all for the interest in design and constructive feedback. We have launched the campaign, it's currently running at https://www.indiegogo.com/projects/raspoe-raspberry-pi-poe-shield#/comments. We generally don't ship out kits anymore, but we might make an exception if you absolutely must have one before the beta-tester tier ships.

[tom66]

Looks interesting.

How much current can be supplied to the Pi? The default Pi configuration will limit to 1.3A max without an ID EEPROM to indicate to the Pi that more current can be drawn. This will limit USB total port current to around 500mA. If you install an ID EEPROM on your board, you can set the bit which indicates the board can supply 10W (5V @ 2A) allowing up to 1A to be drawn from the USB ports. Increases the usability of the widget.

What kind of current limiting do you have on your Pi power output - and does it prevent back-powering via the USB ports?

I like the curved board design - I went with this for a Pi hat I'm designing. I made my board a little shorter though, as it doesn't need the full Pi area.

[fake-name]

Why would you bother with the local transformer? You don't need it to extract power from the 10/100 PoE connection.

I'm also curious why you haven't tied "GNDD" and "GNDA" together. As it is, you're not getting anything from the protection caps right now.

[Monkeh]

Why would you bother with the local transformer? You don't need it to extract power from the 10/100 PoE connection.

You do if the power is on the active pair.

Plus, the Raspi magjack will have a DC path between pairs, and you don't want that. It will be unfortunately low resistance and the smoke will be emitted.

[ojousima]

How much current can be supplied to the Pi? The default Pi configuration will limit to 1.3A max without an ID EEPROM to indicate to the Pi that more current can be drawn. This will limit USB total port current to around 500mA. If you install an ID EEPROM on your board, you can set the bit which indicates the board can supply 10W (5V @ 2A) allowing up to 1A to be drawn from the USB ports. Increases the usability of the widget.

What kind of current limiting do you have on your Pi power output - and does it prevent back-powering via the USB ports?

I like the curved board design - I went with this for a Pi hat I'm designing. I made my board a little shorter though, as it doesn't need the full Pi area.

The DC/DC module could give up to 9 watts, but we'll limit it to 1.3A with a PTC fuse. Fuse itself does not prevent backpowering, but the supply is transformer isolated so no current can flow to other side of isolation barrier. If both higher voltage is present, PoE module will shutdown because the minimum load is not drawn from PoE sourcing equipment.

Thank you for pointing out the ID EEPROMs, I hadn't checked the specification carefully enough since our board does not need any software drivers. Adding a ID EEPROM which would let RPi know that it is backpowered would be a good idea. However, I'm concerned over compatibility with other HATs, as far as I know the EEPROMs are required to have same I2C address 0x50.

We'll ask the community which way would be preferred and we'll go with that. Another thing we need to reconsider is the naming of the board, since we're obviously breaking the HAT specification if it does not have EEPROM. Our board is also too long for a HAT, we probably could squeeze it in official dimensions but it felt reasonable to have Ethernet connectors at same level with RPi.

I'm also curious why you haven't tied "GNDD" and "GNDA" together. As it is, you're not getting anything from the protection caps right now.

We gave this one a lot of consideration. In the end we decided that since the Raspberry Pi does not have a grounded metal enclosure, it would be best to leave shield unconnected on the Raspberry Pi side. If we could rely on having a good ground connection, we would definitely connect the shield to it.

The next version has shielded Ethernet connector, so if the user has shielded cable they can get a bit better noise performance. Protection against electrical transients is given by diodes D1, D3 and D4.

[BurtyB]

As you've said using an ID EEPROM would cause issues if a HAT was plugged in so I'd skip that and drop the HAT name.

You also might want to use the suggested HAT "ideal diode" for back powering over J8 to prevent potential issues.

If you can squish things up a bit you might be able to add a dev area too as SwitchScience have which might come in handy.

[Rasz]

why the hell would anyone want poe splitter as a shield/hat/whatever when you can buy professionally made standalone ones for $15 with free shipping?

[ojousima]

why the hell would anyone want poe splitter as a shield/hat/whatever when you can buy professionally made standalone ones for $15 with free shipping?

Tidiness and compactness of installation, mostly. There are of course cheaper options available, but I'd like to present a counter question: Why would anyone use a $15 standalone when there are $3 USB chargers available with free shipping? 

In some cases this compactness is even a functional requirement. For example our friends at Vaasa Hackerspace are building an open source 3D scanner for human sized objects using Raspberry Pi's and cameras. Since their installation is going to require a lot of Pi's packed tightly, getting rid of any extra wiring is a huge bonus.

[Monkeh]

Why would anyone use a $15 standalone when there are $3 USB chargers available with free shipping? 

Because $3 chargers are liable to try and kill you.

In some cases this compactness is even a functional requirement. For example our friends at Vaasa Hackerspace are building an open source 3D scanner for human sized objects using Raspberry Pi's and cameras. Since their installation is going to require a lot of Pi's packed tightly, getting rid of any extra wiring is a huge bonus.

They might be much, much better off designing an appropriate platform..

[temmi_hoo]

posting this on behalf of ojousima

Raspberry Pi PoE shield now in IndieGoGo!
We have launched our RasPoE, the Power over Ethernet addon board for Raspberry Pi.
For those of you who need to hear no more, here is the link:

https://www.indiegogo.com/projects/raspoe-raspberry-pi-poe-shield

Please spread the word!

There are a few boards like ours on the market, but we are the first GPL3 licensed
one as far as we know. The current design is available at

https://github.com/ojousima/RaspberryPi-PoE

The design is done in KiCAD, which is Open Source electronics design program. We’ll
clear up the schematics and publish full parts list with distributors so you can
even assemble your own boards if you want to! All this is still quite a lot of work,
so please give us a few weeks to polish the design as we publish it.

We’ll work to merge the PCB footprints created for the board back to KiCAD upstream
during the campaign, your backing allows us to expand the common Open framework for
electronics design.

We would like to thank the community and awesome support we have had ever since the
beginning. Especially Vaasa’s Hackerspace’s contribution to us was extremely
important, as they found out about the transient vulnerability in Ethernet PHY of
Raspberry Pi. Open developing of the boards with the community let us find a
critical design flaw, which is now fixed before our release. Even if our campaign is
not successful, the knowledge we gained during this spring is now out in the open
where everyone can benefit from it.

There has been a lot of interest in building derivative works based on our board. As
we’re committed to values of Open Source, we’re always happy to see our designs grow
into something else. Please contact us with your ideas and suggestions, even if it’s
just to let us know that you’re making something cool. This way we can focus at
something else at ELL-i and avoid duplicating work.

And since it was such a long wall of a text, here’s the link again!

https://www.indiegogo.com/projects/raspoe-raspberry-pi-poe-shield

Let’s make the first Open Source Raspberry Pi PoE Board a product!

[theDiver]

There is a Rapberry Pi PoE on kickstarter as well, which is over 100% backed already.

https://www.kickstarter.com/projects/pisupply/pi-poe-switch-hat-power-over-ethernet-for-raspberr

I did back it

[temmi_hoo]

Yeah, we know. That one started just a day before ours. We had already prepared our launch and at that point we thought that even though they got a head start and much higher profile team and pro graphics and all that lets just launch ours and see what happens. We nearly did cancel though as we felt pretty devastated on noticing the Pi Poe just a day before our launch.

I and the rest of our team wish we would have known beforehand so that instead of doing RasPoe we could have done PoE adaptation for some other board, such as a Beaglebone Black.

[Richard Crowley]

I and the rest of our team wish we would have known beforehand so that instead of doing RasPoe we could have done PoE adaptation for some other board, such as a Beaglebone Black.

But isn't most of your R&D work transferable to other SBCs like BBB?

[ojousima]

I and the rest of our team wish we would have known beforehand so that instead of doing RasPoe we could have done PoE adaptation for some other board, such as a Beaglebone Black.

But isn't most of your R&D work transferable to other SBCs like BBB?

It most certainly is, doing next design should be relatively simple. Another great thing in Pi PoE's success is that it brings awareness and PoE-enabled hardware to homes of makers, which in turn lowers the barrier of entry for our next PoE-product.

[Rasz]

people are just retarded :/

http://www.amazon.com/TP-LINK-TL-POE200-Ethernet-Injector-Splitter/dp/B004UBUB7C

[Monkeh]

people are just retarded :/

http://www.amazon.com/TP-LINK-TL-POE200-Ethernet-Injector-Splitter/dp/B004UBUB7C

Wow, and it comes with the DC-DC for that. I'm impressed.

[temmi_hoo]

Not 802.3af, not negotiating, also seems to regulate at injector end...

Standard compliant splitters can be found from eBay at roughly 10eur or so.

The 802.3af/at/etc is nicely designed for the negotiation system. Don't settle for less

Anyhow ours is of course more compact and pretty.

[Monkeh]

Not 802.3af, not negotiating, also seems to regulate at injector end...

No, it's regulated at the splitter. It's not meant to be 802.3af compliant, and it doesn't need to negotiate considering its application.

Standard compliant splitters can be found from eBay at roughly 10eur or so.

And you trust them? They also require a proper PoE switch, I might add, or the whole point is moot.

Anyhow ours is of course more compact and pretty.

That depends what you term pretty..

[theDiver]

Yeah, we know. That one started just a day before ours. We had already prepared our launch and at that point we thought that even though they got a head start and much higher profile team and pro graphics and all that lets just launch ours and see what happens. We nearly did cancel though as we felt pretty devastated on noticing the Pi Poe just a day before our launch.

I and the rest of our team wish we would have known beforehand so that instead of doing RasPoe we could have done PoE adaptation for some other board, such as a Beaglebone Black.

Sorry to hear Was not trying to make your product look bad or anything like that.

Might i suggest a design change that would make your unit stick out.

At a way to draw power to an external harddrive from the PoE unit.

So that it would be possible to have a raspberry pi and an external harddrive powered purely by PoE.

At the moment i use an USB 3 hub to power my harddrive, because the Rapsberry pi in itself can provide enough power. The hub also powers the raspberry pi.