gruvin
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Seriously .. where to find power supply?

Fri Jun 29, 2012 10:36 am

Hello

My Raspberry Pi just arrived and (call me slow but) I've just discovered that it has micro (not mini) power supply socket. Alas, it seems that nearly no one in this country stocks such a power supply -- including element14 (Farnell) from where I purchased the Raspberry Pi itself! The couple of, "cell phone chargers" I have found online do not specify actual current capabilities (or voltage, for that matter) and cost the same or more the the Raspberry Pi itself!

Meanwhile, I have many otherwise suitable 5V power supplies in my junk drawer, whilst none of the literally hundreds of computer cables in the other drawer have micro-USB on either end. :cry:

The R-Pi circuit board itself does not appear to have any markings to indicate where positive or negative could be soldered to. I cannot find any diagrams on this website to indicate same.

Does anybody know exactly where I can solder my own wires? I really don't want to blow this little baby up and I be damned if I'm going to shell out $50+ just for a power supply I already have.

Thanks.

Bryan

[opinion]
Perhaps I'm missing something, but I can't help but wonder how the designers were able to so confidently suggest that this is an easy-to-find, commonplace power socket/supply (as they do in the videos.) From my perspective, here in New Zealand (hardly a 3rd world nation) this micro-USB power supply would in appear to be among the most expensive and difficult power sources in creation. Surely an, "old fashioned" barrel socket would have been just as cheap and easy to deal with in manufacturing -- or at least a couple of clearly marked solder pads? Unlike pricey cell phone chargers of dubious quality and design, there are countless other sources of regulated 5V supplies and barrel plugs abound. Frankly, I think the choice of connector is, well, "amazing." :shock:
[/opinion]

ghans
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Re: Seriously .. where to find power supply?

Fri Jun 29, 2012 11:39 am

The situation is quite different in Europe .. the whole Micro USB standardization thing evolved from the idea of unfair competition or so - and was then formed into legislation which applies to all phone manufacturers.

We now know that chargers , well ,just charge , and aren't proper power supplies.

Head over to the Wiki , you'll find schematics ,GPIO pinouts and even a ARM datasheet.
Yes , you can power the Pi over the GPIO , this bypasses fuses , which have been a major headache anyway.

ghans
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MattHawkinsUK
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Re: Seriously .. where to find power supply?

Fri Jun 29, 2012 11:47 am

Micro USB is used on all new mobile phones and most other small electrical devices. No point putting on a socket that is different to everything else you own. The round power plugs are awful. Every single one I own is a different size.

I'm sure you can buy stuff from ebay from China or Hong Kong as easy as anyone in the UK so I would be amazed if you couldn't buy a micro-usb supply from a thousand different sellers. As for quality just buy a branded one meant for a Smartphone or Blackberry. They are usually rated 700mA to 1000mA.

Micro USB is the perfect choice. Anything else would have been crazy.
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Reider
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Re: Seriously .. where to find power supply?

Fri Jun 29, 2012 11:48 am

Here in the UK a lot of us have several of these PSU types. If it were me I`d be looking for an equivalent to our UK pound shop, where you can buy a bag of mixed adaptors and change the connector type on the PSU you have. Good luck,

Steve

akever
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Re: Seriously .. where to find power supply?

Fri Jun 29, 2012 11:52 am

Here in the U.S.A., I plan to use my Apple brand ipod/iphone wall wart plug (5V, 1A) and a spare micro USB cable. I think this should work since the "Getting Started Guide" says "at least 700mha at 5V.

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leon_heller
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Re: Seriously .. where to find power supply?

Fri Jun 29, 2012 11:54 am

RS sells PSs specifically for the RasPi (5V at 1200 mA). I bought one last Friday, when they were back in stock.
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itimpi
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Re: Seriously .. where to find power supply?

Fri Jun 29, 2012 12:19 pm

I am surprised that people seem to have trouble getting micro USB charging capability. A powered hub with a micro USB cable (possibly the Y variant in some cases) should do, and a powered hub is a good thing to have with the Pi. USB to micro USB cables are easily obtained via Amazon/eBay.

In terms of re-using device chargers, It is always possible to use an iPhone/iPad charger with the addition of a USB to micro USB cable. Another common device with a compatible charger is a Kindle. From what I have seen most chargers aimed at tablet devices are also compatible.

Dilligaf
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Re: Seriously .. where to find power supply?

Fri Jun 29, 2012 7:05 pm

You can power it over gpio pins 2 and 6 or you can solder to TP1 and TP2 test points

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BillyBag2
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Re: Seriously .. where to find power supply?

Fri Jun 29, 2012 11:46 pm

Cheap offerings include buying a USB cable from ebay/seven day shop etc and plugging it in a generic MP3 player charger (iPhone/ipod etc). I've seen a kindle supply used too. Check the ratings but I was surprised that most of the ones I have lining around had enough current. I can not be bothered to squint at the small writing or finding a lamp to read the text. Try taking a snap of the label using your phone. Zooming in can allow you to focus as you can hold the phone further away. Try at 45 degrees if it is glarey. Chargers are available cheaply too but no idea about the quality of clones.
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dashby
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Re: Seriously .. where to find power supply?

Sat Jun 30, 2012 12:33 am

I have just got my Pi and after reading that it was not recommended to connect through USB to PC dug a micro usb psu out that was for a mobile phone. The label when I finally focussed on it says 5v however with a 3 port hub connected my usb wireless adapter that is powered through USB will not power up, this obviously is a problem as I cannot use wifi so cannot do anything that requires the internet.

I realise the phone PSU is not ideal but that is all I have at the moment, can anyone advise as to the best options. I do not have anything apple to use however are these the most reliable power sources to use for the PI?

Thanks

dashby
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Re: Seriously .. where to find power supply?

Sat Jun 30, 2012 1:58 am

The file (RPiPSU) is the phone PSU I have been using, everything working fine until I try to use my WiFi adapter, power does not get through to it. I managed to find a micro USB to USB to connect to a powered hub but still no power going through to my WiFi adapter (EMINENT EM4556 / W BUS 300)http://www.eminent-online.com/en/produc ... apter.html.

Can anyone shed any light into how I can get an internet connection to work with the Pi?

Thanks
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itimpi
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Re: Seriously .. where to find power supply?

Sat Jun 30, 2012 5:25 am

WiFi adapters tend to draw more power than the Pi can supply. If you want to use one it needs to be done via a powered hub.

John_C
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Re: Seriously .. where to find power supply?

Sat Jun 30, 2012 7:59 am

I bought a PSU from RSI when I ordered mine ....... BUT when I got my new Blackberry it had a micro connector and I bought a converter from ebay to convert my old mini sized PSU's to it so I could have them at work and home. This should let you use a mini USB connector with your Pi

itimpi
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Re: Seriously .. where to find power supply?

Sat Jun 30, 2012 8:08 am

John_C wrote:I bought a PSU from RSI when I ordered mine ....... BUT when I got my new Blackberry it had a micro connector and I bought a converter from ebay to convert my old mini sized PSU's to it so I could have them at work and home. This should let you use a mini USB connector with your Pi
Good point. Mini to Micro USB Charger adapters appear to be freely available on Amazon and ebay at very low prices.

dashby
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Re: Seriously .. where to find power supply?

Sat Jun 30, 2012 11:02 am

I have tried a powered hub but still the power will not get through to the WiFi adapter, as far as the connectors I have them but I don't seem to be getting anywhere at the moment. By the label on my RPi PSU is this inadequate ?

Thanks
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gruvin
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Re: Seriously .. where to find power supply?

Sun Jul 01, 2012 1:52 am

Thanks all.

Fortunately for me, my iPhone 'charger' has a USB socket on it, as opposed to a fixed lead, like the notebook supplies. So that should be the easiest route for now. I just have to go find a USB type-A to USB-micro cable -- something I've never yet come across, strangely enough. Hope to find one in a Chinese thrift store ("two dollar shop") :-D

I'm intrigued to learn of the, "USB-micro standard" thing, since such a situation does not exist outside of the UK (Europe?) to the best of my knowledge. (Nor does it make much sense to me, compared to the smaller, more rugged, 2.5mm barrel type, such as that used by Nokia for eons. *shrug*) Here, Nokia still use barrel connectors, most every Android device I've seen used mini-USB, as do cameras and other such devices. Or perhaps I've spent just a little too long under my rock of late? The world is changing so fast nowadays -- anything could have happen in the past week. hehe

gruvin
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Re: Seriously .. where to find power supply?

Sun Jul 01, 2012 1:59 am

itimpi wrote:I am surprised that people seem to have trouble getting micro USB charging capability. A powered hub with a micro USB cable (possibly the Y variant in some cases) should do ...
The Rasp-Pi Getting Started guide explicitly states that a powered hub will NOT suffice. (500mA current limit beignet he reason, I suppose.)

gruvin
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Re: Seriously .. where to find power supply?

Sun Jul 01, 2012 2:06 am

Dilligaf wrote:You can power it over gpio pins 2 and 6 or you can solder to TP1 and TP2 test points
What voltage? 5V or 3.3V? Without a schematic, I cannot tell if these points are pre- or post- regulator. My best guess would be post-regulator. (The SE8117T33 is a 3.3V regulator.)

Can you direct me to a URL in the wiki where the board details or schematics can be found? I cannot find either for the looking (yet). Thanks.

gruvin
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Re: Seriously .. where to find power supply?

Sun Jul 01, 2012 2:07 am

Ah ... have now found this http://elinux.org/RPi_Hardware.

Thanks.
Dilligaf wrote:You can power it over gpio pins 2 and 6 or you can solder to TP1 and TP2 test points

gruvin
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Re: Seriously .. where to find power supply?

Sun Jul 01, 2012 2:10 am

Oh dear ... it says here http://elinux.org/RPi_Hardware that ..

"It has been reported by a number of users that Apple iPhone and iPad USB power supplies are inadequate for powering the R-Pi. "

I'm going to fall back on my 5V, 3A supply, connected to TP2(+5V) and TP1(GND). Hopefully there will not be smoke.

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mahjongg
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Re: Seriously .. where to find power supply?

Sun Jul 01, 2012 2:10 am

What voltage? 5V or 3.3V? Without a schematic, I cannot tell if these points are pre- or post- regulator. My best guess would be post-regulator. (The SE8117T33 is a 3.3V regulator.)
How would you put 5V back through the 3V3 regulator? 3V3 regulators cannot convert 3V3 back to 5V, and 5V is what everything else needs.

Obviously you power it with the same voltage as you would normally, with 5V. Just like the pinheader documentation (pin 2 = 5V and pin 6 = GND) and numerous sources about TP1 and TP2 would tell you.

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mahjongg
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Re: Seriously .. where to find power supply?

Sun Jul 01, 2012 2:18 am

As long as yo do not buy a piece of junk too-cheap-to-be-true 5V charger, most chargers that can deliver at a minimum 700mA, and would keep up at least 4.8 Volt while doing it, would normally work

This is an example of what not to buy!
http://www.youtube.com/watch?v=T88ej64aXUM&feature=plcp

Dilligaf
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Re: Seriously .. where to find power supply?

Sun Jul 01, 2012 2:19 am

gruvin wrote:Oh dear ... it says here http://elinux.org/RPi_Hardware that ..

"It has been reported by a number of users that Apple iPhone and iPad USB power supplies are inadequate for powering the R-Pi. "

I'm going to fall back on my 5V, 3A supply, connected to TP2(+5V) and TP1(GND). Hopefully there will not be smoke.
Yes, it's 5 volts, but double check polarity. If I remember correctly TP1 is positive (5V) and TP2 is negative (ground)

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mahjongg
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Re: Seriously .. where to find power supply?

Sun Jul 01, 2012 2:23 am

@dilligaf You remember correctly.

gruvin
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Re: Seriously .. where to find power supply?

Sun Jul 01, 2012 2:46 am

Doh. Lysdexia strikes again. TP1 is +5V, TP2 is GND (I stated above and enacted the opposite). So in fact, I just smoked my R-Pi.

Al this for the lack of a commonly available power connector. Far out. :shock:

Stuffed if I know how the target "3rd world" folks are going to get on. I for one give up. Back to real computers for me.

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