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UCTRONICS PoE HAT for Raspberry Pi 4, Mini Power Over Ethernet Expansion Board for Raspberry Pi 4 B 3 B+, with Cooling Fan

£9.9£99Clearance
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So I don't understand what I'm doing to kill these Pi's. I'm wondering if anyone has any insight here. Then connect the Raspberry Pi PoE+ HAT to the two 0.1" headers (40 + 4) that are fitted on your Raspberry Pi Dominic 1:10: I can’t say if that’s James’s plan or not. But that appears to be the starting point. So I bought a replacement Raspberry Pi 4. I was able to boot it with the same SD card, with no changes to it's contents. Ubuntu came up just fine. It seemed to work exactly as the previous one had.

The announcement blog post details the major differences, but there were two things I really wanted to dig into:

More Launch Problems?

Dominic 3:18: Through the switch. Yes. And then it applies a voltage to the cable, to then try and detect a resistor of a particular value. And if it can detect that, then it knows which power range available. There are more advanced methods for the higher, for PoE++ that we were referring to, but we don’t do that, so no need to describe how all that magic works. With the HAT mounted, I first tested the fan; the old HAT was a little annoying (but not too obtrusive) when it's fan was going full blast. Well, I compared the new ADDA fan (2.4 CFM at 12k RPM) to the old Sunon fan (2.2 CFM at 10k RPM), and here are the results: HAT 🎩 For a full list of local and regional product approvals, please visit www.raspberrypi.org/compliance Now, before you get all excited, you have to make sure you have a PoE+ switch or injector. A lot of cheaper and older PoE devices only support the older af standard, so you'd still only get 13W. PoE+ Switch Dominic 9:23: Yes. And so it had this big hole in the middle of the PCB, so there was a lot of wastage of the PCB, because it just gets thrown away —

The Raspberry Pi 4 came along, and suddenly the board itself can pull over 7 watts at load. Combined with 6 watts of power for a hungry USB device or two, and we’ve exceeded the nominal 12.5 watt power budget. As a result, a handful of users that were trying to use the Pi 4 with POE were hitting power issues when powering something like dual SSD drives over USB. The obvious solution is to make the PoE HAT provide more power, but the original HAT was already at the limit of 802.3af PoE could provide, with a maximum power output of 12.95 watts. The fan position on the new PoE+ HAT has changed so now the ventilation slots in the new Uputronics GPS HAT for example obscure the fan. May be an issue with other HATS? Eben 6:07: When I think about transformers, I think about a sort of a ferrite core with some windings —So, might not be a new issue, just a reoccurence of an old one. It may not be related to the PoE HAT, just that adding one is making the issue appear in these two cases. Dominic 3:09: It does it by — first of all, it looks for some capacitance on the cable to know that there is something there. And then — And that's because the first PoE HAT used the 802.3af standard. It only guarantees up to about 13W of power to a "powered device" like the Raspberry Pi. Eben 7:25: I remember the first time I saw one of those: I mean, it’s such a beautiful little space-age solid-state bit of stuff, right? It really does look beautiful.

Eben 8:47: So this thing is a — I think there’ve been a lot of debates as to whether it’s a compliant, er — is it a compliant HAT? Is there a requirement that a HAT has PCB in all of the places that a HAT can have PCB? But yeah, so this thing is L-shaped; now what does that let us do? Eben 8:21: So we’ve built, rather than buying a transformer from somebody else, we’ve actually built our own transformer on our own PCB, and we just put a ferrite around it. We didn’t inquire as to whether our field testers were using high-current peripherals (they weren’t) When using PoE, not all devices are compliant. Thus, there is a need of either an injector or splitter for your PoE switch to be able to connect to a non-PoE device. Source: Versatek Source: Versatek Hopefully this coil whine or whatever it is doesn't indicate a deeper issue—I haven't had time to dig in much, but it's really unpleasant to hear in person.

In case it comes up, yes, I have my PoE switch (Meraki MS220-24P) plugged into a UPS, but my comment above is about having an option to have PoE-powered Pis (ideally a hat, not a 3rd party splitter) also have onboard device-local UPS to keep the Pi running for 30 minutes or so until PoE is restored. I repeated the experiment with the original PoE HAT, and you can review my raw results if you’d like. There are a couple minor caveats, mostly related to temperature measurement. My IR Thermometer doesn’t provide the rich data that a full IR camera does. Additionally, I was limited to measuring just one side of the PoE boards. I believe that the hottest spots on the original PoE HAT are on the underside of the board, while on the new HAT, seem to be on the side facing away from the Pi — that’s a win in itself. All that to say, my temperature measurements of the original HAT are probably quite a bit too low. More Launch Problems?

Dominic 5:20: So we’ve dropped — it becomes 90% efficient instead of… a lot less percent efficient. As of 04/03/21: Enlarged HDMI cut-outs to fully accommodate cables. Removed Raspberry Pi 3 compatibility. Thanks to improved thermal design it should run cooler (measured at the hottest point on an uncased board) at any load. It does seem the PoE HAT having a better power supply than your PSU is what's causing your problem. Production lifetime: The Raspberry Pi PoE+ HAT will remain in production until at least January 2027And further, I'm wondering if I need to fundamentally rethink this project as it seems like the way I'm setting things up will always kill the Pi. Furthermore, PoE can be easily moved around and reconnected. It is like plug and play where an entire network doesn’t have to be dismantled if you wish to move it around. Only power with PoE HAT works fine, RPI is working fine (no sudden restarts or anything like that), just eth0 link does not work. The latest version of the Picade X HAT uses a Type-C connector, which means that it provides enough juice to power either a Raspberry Pi 4 or an earlier model. Older versions of the X HAT, which may still be on sale, use a microUSB connector that only has enough juice for a Pi 3 or earlier. The Raspberry Pi PoE+ HAT is an improved Power over Ethernet add-on board, compatible with any Raspberry Pi with PoE pins (including Raspberry Pi 3B+ and Raspberry Pi 4).

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