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Raspberry Pi Releases new PoE+ Hat
- tonyedgecombe 5y agoI love the transformer, I wonder how they came up with that idea.
- schappim 5y agoThe Planar transformer[1] is a big upgrade from the traditional Wire-wound. [1] https://en.wikipedia.org/wiki/Planar_transformer https://en.wikipedia.org/wiki/Planar_transformer
- ksec 5y agoEven wiki only list Advantages over conventional counterparts, what are the trade offs and drawbacks? These days everyone is busy telling me all the benefits of something without telling me the price / cost / cons. I need facts so I could make up my mind. Not a marketing pieces.
- arbitrage 5y agothe primary use here is because of its smaller size. the tradeoff is increased cost, complexity, and low overall power throughput related to size. which isn't really a problem for the RPi form factor -- but this wouldn't be indicated for higher current draw applications like radio, or audio i would suspect.
- deleted 5y ago[deleted]
- yarcob 5y agoI wonder why they don't integrate the transformer in the circuit board, that would be even more elegant. Does the transformer PCB have more layers or heavier copper than the rest of the board?
- arbitrage 5y agothe transformer does a lot of induction. you don't want that in your PCB; offset in a separate component is a better plan, especially considering this is a budget PCB and there's only so much mitigation they can do with the circuitry and mass production involved.
- Renaud 5y agoIt would not be economical to do this unless the board is small. The PCB for the transformer is especially tuned for its performance: what dielectric is used, what copper weight, what distance between layers, how many layers, all these are complex parameters that need to be tightly controlled. On the other hand, for the rest of the board, the PCB can easily get away with 4 layers on standard FR4 which is cheap to fabricate. Using these low profile transformers is getting common, especially if you can't afford the height of a standard transformer on just one side of the PCB. You should look into the magical stuff that powers small DC to DC power supplies: transformers entirely made of PCB, tight integration of the components inside the PCB itself sometimes. It's quite amazing really (and this is 5 years old, so imagine the progress made since): https://www.youtube.com/watch?v=K6om51cr8Mk https://www.youtube.com/watch?v=K6om51cr8Mk
- yarcob 5y agoThanks for the video! Curiously, many of the boards in the video with planar transformers have the inductor integrated in the board rather than on a daughter board, so despite the difficulties it seems like it should be doable. Maybe for revision 3 of the POE hat.
- tomn 5y agoIn the smaller ones, the planar transformer takes up most of the board area, so there's no benefit to assembling two different PCBs. The larger DC-DC converters are not as cost sensitive as a raspberry pi product; they tend to be used in low volume industrial/scientific/medical devices and might cost £70 each. When you consider that they are also mostly inductor by area, and factor in the additional complexity of manufacturing a multiple-pcb assembly, it's also not worth it. IIRC there are also some larger PCBs in that video; for those it's possible that they already had enough layers for routing signals that it was easy to integrate the transformer core directly. Another factor I haven't seen mentioned is the manufacturing complexity. It looks like the transformer could be placed by a normal pick and place machine, while assembling a transformer around a PCB would be more of a specialised or manual process. I suspect that might be the real reason, as the transformer PCB doesn't look like it has that many layers.
- afandian 5y agoCheck out Carl Bugeja's videos. He's doing some crazy things with PCB-based motors. https://twitter.com/BugejaCarl https://twitter.com/BugejaCarl https://www.youtube.com/carlbugeja https://www.youtube.com/carlbugeja
- gaudat 5y agoThat is a power module made by Murata IIRC. I am jellying at that thick multilayer board.
- sneak 5y agoBe advised that PoE splitters for rpi are also available from third parties for around $15.
- gsich 5y agoAnd those are more usable for other devices with their general power jack (or USB) The Pi Hat only works for ... the Pi.
- Macha 5y agoAnd also leaves the GPIO pins free for other uses
- vetinari 5y ago802.11at or passive?
- zeroping 5y agoI have had three cheap ones in that price range fail. I suspect the Pi Hat version is better designed.
- sonium 5y agoI am always wondering that there seems to be demand for a PoE hat. I have never heard of anyone using it. So who uses it? Also how large is Raspberry Pi’s share in commercial applications?
- rcxdude 5y agoI use one for a raspberry pi running a VPN, because it was a bit more convenient in terms of wiring (everything else on the network is also already PoE).
- grandsham 5y agoIt's not a commercial application, but I have 2 raspberry pis rack-mounted[i] running some utilities for my home network (pi hole, gps-based NTP, ads-b data for FlightAware). Using PoE means no USB power bricks, no USB cables running all over the rack, and one less thing I need to plug into my UPS. [i] https://www.amazon.com/dp/B08F9X528J https://www.amazon.com/dp/B08F9X528J
- opencl 5y agoI've seen them used in an industrial setting, just to run a browser-based ERP client. Makes the wiring a little bit nicer.
- m-p-3 5y agoI've seen some of these used for digital signage with PoE and network boot. That way you can remotely power-cycle it and it grabs the OS and its config from the network at boot. It makes the rollout of updated system images quite seamless.
- geerlingguy 5y agoIt's great for racking Pis (e.g. my setup that I just posted about last week: https://www.youtube.com/watch?v=LcuNc4jz-iU https://www.youtube.com/watch?v=LcuNc4jz-iU), and also when you want to use a Pi in some location where running a power line would be cost prohibitive but running an Ethernet cable with PoE would be okay (for many, you have to have an electrician do the former, and likely get a permit).
- 5y ago
- mtlynch 5y ago>In general, we’re weathering the shortage very well, and the supply of mainline Raspberry Pi computers, Zeros and our other products have not been affected (we’re very good at pipelining). This is a surprisingly false claim. I make a Pi-based product,[0] and there have been Pi shortages throughout 2021. Right now, I'm struggling to find any vendor that has Pi 4B 2GB or 4GB for anything more than one per customer. [0] https://tinypilotkvm.com https://tinypilotkvm.com
- numpad0 5y agoCould it be primarily English shortage? At least one of my go-to store says “4+ months of stock” and couple others from the Foundation’s store finder shows them available. Not that I doubt the shortage but if you’re desperate finding some.
- mtlynch 5y agoOh, that could be. In which country are you seeing Pi 4s in stock? All the vendors in North America are out, and Chinese suppliers on AliBaba are charging 2x the normal retail price.
- guenthert 5y ago??? Central Computers (NA with Chinese ties) seems to have some available right now (5/24/2021): https://www.centralcomputer.com/catalogsearch/result/?q=raspberry+pi4 https://www.centralcomputer.com/catalogsearch/result/?q=rasp...
- xony 5y agoPOE without ethernet
- guenthert 5y agoA new PoW Hat. Something wrong with the old one? https://www.youtube.com/watch?v=Tpvjo6wDFUA https://www.youtube.com/watch?v=Tpvjo6wDFUA Other then that it was running pretty hot, there seems to have been an unforeseen interaction between the switching regulator and the USB current limitor: https://www.theregister.co.uk/2018/09/11/raspberry_pi_poe_hat_issue/ https://www.theregister.co.uk/2018/09/11/raspberry_pi_poe_ha... (those problems are actually mentioned in the article)
- bchjnes69 5y agoI have several and they have an annoying high pitched whine.