stevep
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First impressions - power, usb etc

Tue Jun 05, 2012 10:03 am

Finally got some peripherals sorted and started the 'get it running' process. Used the Wiki Peripherals page to select some of the bits needed, and the tutorials on Wiki to prepare the Samsung 4GB SDHC card (done on a Mac, using a £6 SanDisk card reader bought from Curry's). Had to resize the partition on the Pi itself later on. No apparent problems with the SD card or the card reader.
Apart from the bits mentioned above, I used (or attempted to use) the following, with varying degrees of success:

Kensington Dome 7 port powered usb hub model 1500129 - Cannot get a mouse to work when this hub is used. Have tried the k/b and mouse plugged into the hub; k/b into hub and mouse into Pi; and k/b into hub and mouse into k/b. In all cases the mouse works initially and then stops working after Startx.
Apple keyboard A1048 - seems to work inconsistently. Getting a lot of repeat keystrokes, whether plugged into the hub or into the Pi.
Microsoft Basic Intellimouse 1.0A, black, 2 button+scroll - works when plugged into the pi, and when the usb hub is not connected.
HDMI cable and hdmi/div adaptor from Toolstation (chosen because they were cheap).

For the power supply I have tried 3 different ones:
Apple iPod charger (originally supplied with a 4g iPod 20gB Photo), rated at 5v, 1.0A. Actual voltage across TP1/TP2 4.82v. Issues with keyboard repeats preventing logging in, so couldn't measure the voltage when running the GUI.
Apple iPad charger (as supplied with iPad2), model A1357, rated at 5.1v, 2.1A. Actual measured voltage 4.74v. Same k/b issues as above.
Maplin micro usb power supply, code N19HX, http://www.maplin.co.uk/micro-usb-power-supply-393067. Actual measured voltage 4.85v.
(I also tried powering the Pi from the Kensington usb hub, but have seen a few conflicting opinions on whether this is wise. Will have to do some more research on this).

Impressions so far -
Choice of peripherals is hit and miss. Even using the Wiki Peripherals information, you can't seem to guarantee that any particular selection will work correctly either with the Pi, or with each other. There is a fair bit of information on working peripherals, but it is very widely spread and difficult to research.
The Pi itself seems incredibly sensitive to power supply and usb issues. I'm well aware that this is the first production run, but these seem rather too fundamental not to have been addressed before now (even if only too the extent of the Foundation supplying a list of known, working and recommended peripherals).
You don't necessarily get what you pay for - for instance, based on my experience I wouldn't recommend the Apple k/b or the Kensington hub, both quite expensive items.
On the few occasions I have managed to successfully enter the name/password, and start the gui with a working mouse, I am quite impressed with the speed - certainly better than I had been led to expect, and more than adequate for a bit of Python control work.

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nick.mccloud
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Re: First impressions - power, usb etc

Tue Jun 05, 2012 11:07 am

stevep wrote:For the power supply I have tried 3 different ones:
Apple iPod charger (originally supplied with a 4g iPod 20gB Photo), rated at 5v, 1.0A. Actual voltage across TP1/TP2 4.82v. Issues with keyboard repeats preventing logging in, so couldn't measure the voltage when running the GUI.
Apple iPad charger (as supplied with iPad2), model A1357, rated at 5.1v, 2.1A. Actual measured voltage 4.74v. Same k/b issues as above.
Maplin micro usb power supply, code N19HX, http://www.maplin.co.uk/micro-usb-power-supply-393067. Actual measured voltage 4.85v.
Are you using the same cable each time? I'm using an iPad 2 charger and it didn't work with the first cable I tried but works absolutely fine with a Samsung phone cable.

As to testing all this out, this is what this phase of the project is all about - the 'developer' release.

stevep
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Re: First impressions - power, usb etc

Tue Jun 05, 2012 11:56 am

I'm starting to suspect the power cable - although it looks quite good quality (I think it's from a Garmin satnav) I might just be looking at some very thick sleeving rather than a decent thickness of copper conductor.
As to testing all this out, this is what this phase of the project is all about - the 'developer' release.
Don't know what you mean by this. I did some testing and documented the results. Have I missed something?

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mahjongg
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Re: First impressions - power, usb etc

Tue Jun 05, 2012 12:13 pm

These first devices are considered for developers only!
Originally there would only be 10.000 or so made, exclusively for developers, but market pressure decided differently
A stable real release, the so called "educational release" (with a case, reliable drivers including floating point support, and GPU accelerated 2D graphics rendering, preselected peripherals, educational software etc etc etc) isn't expected until end this year.

Until then we are all "beta testers".

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oztrailrider
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Re: First impressions - power, usb etc

Tue Jun 05, 2012 12:54 pm

Power certainly seems to be the most sensitive issue with the Pi, even down to cable choice. I imagine all of this should hopefully stabilise in time, perhaps some minor revisions to the hardware could help to alleviate this. I hope you manage to get it all working. Did you have any issues with the hub when connected to a PC?.

stevep
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Re: First impressions - power, usb etc

Tue Jun 05, 2012 1:10 pm

mahjongg wrote:These first devices are considered for developers only!
I know. I don't understand why you are making this point though.

Re the hub, it has worked perfectly on my Mac laptop. I have yet to pop the back off it to check the voltage, or see if any of the ports are 'straight through' in terms of power.
Just off to see if I can get a different hub and swop the power supply for something different at Maplins (This is getting expensive!).

stevep
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Update: First impressions - power, usb etc

Tue Jun 05, 2012 8:51 pm

Have now tried a new Belkin F5U701 7 port powered hub, along with a Belkin usb/usb micro cable to supply the power from the hub to the Pi. The data cable from the Pi to the hub has had the red-wire snip, so I'm not putting power back to the Pi through its' usb ports. Voltage measured at 4.81, so still a bit on the low side. Still using an Apple keyboard and MS Intellimouse.
I have also tried using a seperate (Apple) power supply, along with the Belkin hub, resulting in 4.82v at TP1/TP2.
I'm still getting the key-repeat problems, I'd say around 3 boot-ups out of 4, which makes logging in impossible. The mouse still blanks out when starting the GUI as well. The good news is that if I hot-swop the k/b and mouse usb plugs around I can usually get them to work, that is after the GUI is running. Bad news is that for some reason I have not started to investigate I have lost the network connection.

hippy
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Re: First impressions - power, usb etc

Tue Jun 05, 2012 11:14 pm

stevep wrote:
mahjongg wrote:These first devices are considered for developers only!
I know. I don't understand why you are making this point though.
Just to point out that you cannot expect anything or everything to work and there not to be any problems, some things you may have expected to be addressed may not have been.

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jbeale
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Re: First impressions - power, usb etc

Tue Jun 05, 2012 11:25 pm

Actual voltage across TP1/TP2 4.82v. Issues with keyboard repeats preventing logging in, so couldn't measure the voltage when running the GUI.
People have reported full function down to about 4.6 V, so I don't think we can necessarily blame just a power cable here. I think there are some remaining USB driver problems. For example, this issue "USB dropped packets" is not yet resolved: http://www.raspberrypi.org/phpBB3/viewt ... =28&t=5249

stevep
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Re: First impressions - power, usb etc

Wed Jun 06, 2012 9:35 am

jbeale wrote:
Actual voltage across TP1/TP2 4.82v. Issues with keyboard repeats preventing logging in, so couldn't measure the voltage when running the GUI.
People have reported full function down to about 4.6 V, so I don't think we can necessarily blame just a power cable here. I think there are some remaining USB driver problems. For example, this issue "USB dropped packets" is not yet resolved: http://www.raspberrypi.org/phpBB3/viewt ... =28&t=5249
Yes, thanks for that link. I've been doing a bit of digging and searching, and while I'm sure some power supplies and cables are not up to the job I get the feeling that there are other software/firmware related problems as well. Hopefully in time the clever software guys will be able to issue updates that will improve things. I also think there may be issues with different combinations of hardware that don't play nicely with each other - almost impossible to sort out in the short term as there are so many possible combinations!
A practical workaround (at least for my particular plans) is to remotely access the Pi from my desktop box.

stevep
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Another update: First impressions - power, usb etc

Wed Jun 06, 2012 5:34 pm

Took the Belkin USB Hub back for a refund and bought yet another (from PC World of all places) - a Logik LP4HUB10, along with their cheapest k/board (a bright pink Logik LKBWC11 for a fiver :o ).
I was rather hoping to power the Pi from the hub, but it didn't want to know, so it's powered by my iPad charger at the moment. Mouse is now a MS 5 button Intellimouse borrowed from my desktop machine, though the other 3 button Intellimouse also works fine. Pleased to say it now seems to be running well. I have yet to try some of the other peripherals I've used for previous attempts to isolate where all the initial problems occurred (though as I said above I suspect it might be a combination).
Was hoping to be able to post from the Pi just for the hell of it, but Midori is very slow and crashes frequently. I remain impressed that such a low power device is able to run a desktop environment, although I'm glad that my plans don't involve using it to any great extent.

markcd
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Re: First impressions - power, usb etc

Wed Jun 06, 2012 7:10 pm

that's odd... I also bought an LP4HUB10 from PC World and I have had no problems with powering the Pi from it. So far I've only has a basic Dell USB keyboard plugged in too. Maybe the cable is an issue? For info, I'm using the cheapest cable I could get from Amazon - the link is here:

http://www.amazon.co.uk/gp/product/B001 ... 02_s00_i00

which came in at a whopping 92p!

philipm
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Re: Another update: First impressions - power, usb etc

Thu Jun 07, 2012 9:19 am

stevep wrote: Was hoping to be able to post from the Pi just for the hell of it, but Midori is very slow and crashes frequently. I remain impressed that such a low power device is able to run a desktop environment, although I'm glad that my plans don't involve using it to any great extent.
I got sick of Midori crashing whenever I breathed too loudly so I'm trying Chromium, which hasn't crashed so far, though it's a tad slow, and has no way of setting proxies, so I had to do that by setting a global shell variable (unless I'm missing something, there's no sysdmin GUI tool set up yet to do this).

Installing Chromium ran me into another problem: aptitude on big installs can wedge the system, probably running out of memory (a hazard of having no swap). I tried again with nothing else running and it installed with no problem.

BlowingRaspberries
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Re: First impressions - power, usb etc

Thu Jun 07, 2012 9:49 am

My set-up's pretty minimalist - Kindle charger (one old HTC one I had seemed not to give quite enough power cause USB not to work well), and a bit of ethernet cable into a router.

That's it.

Use it mostly via a MacBook.

stevep
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Re: First impressions - power, usb etc

Thu Jun 07, 2012 9:55 am

Yes, I too binned Midori last night and put Chromium on instead, and it seems to work much more smoothly.
I also played with vnc, which seemed to work quite well.

@Philipm
I'm slightly baffled with my SD card setup though - following the guide in the June edition of MagPi, and using gparted on my Virtualbox/Mac my setup looks completely different, with no swap file showing. I have obviously missed something fairly simple, and haven't found any references to this apart from your comment:
a hazard of having no swap

stevep
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Re: First impressions - power, usb etc

Thu Jun 07, 2012 10:57 am

Re Markcd's post about the usb hub (the Logik LP4HUB10 from PC World) - I took the cover off and had a quick look - the 5v from the supply seems to be routed direct to all the ports. I decided to snip the red wire on the cable fairly close to the circuit board (just allowing enough so I can solder it back on if necessary). Just connected everything back together and am now powering the Pi direct from the hub with no apparent problems (ie network connection, k/b and mouse working fine). Voltage at usb hub is 5.10v, and across TP1/2 is 4.80v when the Pi is booted and running LXDE.

So for anyone who has yet to buy any peripherals, here is a working combination:
POWER: Taken from usb hub
HUB: Logik LP4HUB10 from PC World, £12.99
KEYBOARD: Logik LKBWC11 from PC World (in tasteful pink at £4.99, other colours available
SD CARD: Samsung 4gB SDHC card from Maplins, their code A94LA, £8.99
DISPLAY: HDMI cable and DVI adaptor from Toolstation, codes 10412 and 67906, total £9.87. Linked to a Hanns:G 19" HW191D monitor
POWER: Usb to micro usb cable, unknown but maybe from a Garmin satnav.
SD READER: SanDisk ImageMate Multicard reader, £4.99 from Currys

As a few others have pointed out, the peripherals cost more than the Pi....

philipm
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Re: First impressions - power, usb etc

Thu Jun 07, 2012 5:00 pm

stevep wrote:Yes, I too binned Midori last night and put Chromium on instead, and it seems to work much more smoothly.
I also played with vnc, which seemed to work quite well.

@Philipm
I'm slightly baffled with my SD card setup though - following the guide in the June edition of MagPi, and using gparted on my Virtualbox/Mac my setup looks completely different, with no swap file showing. I have obviously missed something fairly simple, and haven't found any references to this apart from your comment:
a hazard of having no swap
On one of the forums or the wiki, I forget which, I followed the instructions to repartition on the Pi (using gparted as I recall). Those instructions claimed there's no need for swap (or it's inefficient on flash) and sure enough, if you check /etc/fstab, you'll find the line defining the swap partition commented out:

$ cat /etc/fstab
proc /proc proc defaults 0 0
/dev/mmcblk0p1 /boot vfat defaults 0 0
#/dev/mmcblk0p3 none swap sw 0 0

Genius23008
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Re: First impressions - power, usb etc

Sat Jun 09, 2012 9:25 am

USB hubs might power the Pi but again may not. USB ports are designed to output only 500mah and, even though it can run on 440mah (not in GUI), chances are it will not be stable enough for normal use. You may find that some PCs or laptops have a specially designed 'charging' port outputting 1A, but this is still a growing idea that isn't on many of them. Some computers allow a tiny bit of room for more power - my test showed that my PC was actually outputting 850mah to my external hard drive. In short, you probably will get it running on a hub properly but it won't be stable enough for proper use.

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rew
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Re: First impressions - power, usb etc

Sun Jun 10, 2012 6:25 am

you should get your units right. mah is a misspelling for mAh, which is wrong because you're trying to say mA.

My 'pi runs just fine off the 400mAh battery that I have... It still draws 440mA, causing the battery to drain within less than one hour.....
Check out our raspberry pi addons: https://www.bitwizard.nl/shop/

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rurwin
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Re: First impressions - power, usb etc

Sun Jun 10, 2012 7:30 am

A good way to remember the case of units: if it's named after someone then the unit is written with a lower-case, but the abbreviation is upper-case. So it's "ampere", but "A".

"a" is an abbreviation for "are", which is 100 square metres. It's one of the ones we never use; we multiply it by 100 and use hectare (ha) instead, which is 10,000 square metres.

So one "ma" would be a milli-are, and would be about 3 square metres.

"MA" of course would be a mega-amp, and not the sort of thing to have around a Raspberry Pi.

[/pedantic]

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