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USB peripherals, performance and power management

Sat Jun 02, 2012 4:40 pm

I suspect that:
1. Schools will connect their RPi to the mains using the micro USB port.
2. Schools will attach their existing keyboards and mice to the RPi.
Some devices will work, but some won't and some will impact on the performance of the RPi.
3.The suggested solution initially (Magpi 2) appears to be a powered USB hub.
Some devices will work, but some won't and some will impact on the performance of the RPi.
4. This may get the RPi a name as being slow, un-reliable and too time consuming to persist with.
5. Schools will not be disposed to buying new "authorised" keyboards, mice etc.

Serious consideration is hopefully being given to improving the power management situation before the RPi goes out to schools. I trust is already well in hand and it was wholly un-necessary for me to wake up in the middle of the night in a cold sweat worrying about it.

kind regards

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Raspberry Pi Foundation Employee & Forum Moderator
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Re: USB peripherals, performance and power management

Sat Jun 02, 2012 6:03 pm

Initially the only schools that are going to buy this version of the RasPberry Pi in any large numbers will typically a) have a Head of ICT/Computing who has qualifications in and/or industry experience of computing b) have a Head Teacher who supports the teaching of computing c) have an understanding and helpful network manager. Each of these things is currently rare: coming across all three in the same school would be like being hit on the head by a meteorite as you went to collect your Lotto jackpot, and waking from surgery to find that the anaesthetist was your long lost identical twin. For most schools, signing up to teach GCSE Computing for the first time in a decade is a big enough step without buying in innovative, unproven hardware.

So, by definition, the schools that buy them will have thought about the existing problems and be equipped to deal with future issues - more than this, they will be contributing to the Raspberry Pi's (pedagogical) body of knowledge and creating teaching resources. Next year, as more and more schools climb aboard the Happy Computing Bus, the teething problems should have been sorted and there will be a robust teaching community using this and other tools to teach computing and computational thinking. We hope ;)

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Gert van Loo
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Re: USB peripherals, performance and power management

Wed Jun 06, 2012 8:02 pm

There will be a 'school' pi kit which will be complete (except TV).
So: Pi-board in a box + PSU + SD-card (Fully programmed) + Keyboard.

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Re: USB peripherals, performance and power management

Fri Jun 08, 2012 10:52 pm

Gert van Loo wrote:There will be a 'school' pi kit which will be complete (except TV).
So: Pi-board in a box + PSU + SD-card (Fully programmed) + Keyboard.
Hi Gert,

Is there any predicted date when the kit will be available?

Thanks and best regards,


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Re: USB peripherals, performance and power management

Fri Jun 29, 2012 11:10 pm

I'm a primary school teacher and although I have no industry experience or computing qualifications I am a keen hobbyist. I can only speak for Primary's below but I think some of this will replicate to secondary schools.

I don't think the issues are going to be keyboards and mice, power supplies or getting the operating system loaded onto the pi at all. For example I just stuck my Tesco value keyboard in and a random mouse I had lying around and off I went and any idiot can follow the quick start instructions (I did!) I think the problem is going to be having someone with enough imagination to see what you can do with it after initial setup.

For example, I know nothing about Linux at all and while I was aware of issues with drivers I had no idea of the complexity and the problems with availability (although I realise this could be an issue with keyboards etc I'm sure it won't be as big a deal). Anyway, in my head I had a project I could do with our Year 6 (10 going on 11 yo) using scratch and a Lego WeDo usb hub to make remote control cars programming with the appropriate Scratch modules. If I could battery pack the RPi, include a wireless keyboard then it could be completely self contained and racing around. The problem I've got is no drivers for a Lego usb hub and I have no idea where to start or where to go to do it after quite a lot of searching and mistakenly trying to install an i386.deb file instead of an armel (and I still need to get my head round this side of things).

So now I'm back to a text program to generate something on screen... but I can do that on a normal laptop/desktop and it's not much different whether it's on debian or windows. What I need is accessible projects which utilise the Pi but also give me a reason for doing it on the credit card sized computer rather than the desktop/laptop.

There is a lot out there and I'm genuinely looking but I can honestly say that with my level of knowledge I feel like I'm on a massive learning curve and so I know that to get this into a Primary School Environment (although I realise for most it's aimed at secondary) it's going to be even steeper for the vast majority of primary teachers and since they teach every subject it could be a massive training issue.

The best thing I can think of at the moment is that I'm not afraid to give kids an SD card and a couple of utilities already installed on our general purpose machines teach them to install an operating system and then let them install programs on the RPi. However my own experience thus far is already telling me that to install programs on the Pi is going to be harder than I initially thought (I now appreciate install wizards!) and so I wonder how practical this would be for whole class teaching.

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Re: USB peripherals, performance and power management

Fri Jul 27, 2012 3:26 am

There is a list of hardware which is known to work with the pi. This should be posted
as a sticky in every one of these forums. At the same time anything that can be
done to make the usb bus more tolerant of different v1.1devices is important.
A $35 computer may not be so cheap if you have to buy a new keyboard, mouse
and usb hub to get it to work.

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Re: USB peripherals, performance and power management

Sun Aug 26, 2012 7:00 pm

One approach may be to enlist the help of bright 14+ year olds to propose, implement and write up such tasks as
i) Chop up spare +5V and 0V lines in an older desktop PC, fit a suitable fuse, and solder on new power supply wires to all of the rPi boards on a benchtop. Report on import cost savings and labour hours worked vs buying new micro-usb supplies for each. A-level economics essay question: why do people in the uk throw away so many AC to DC power adapters ?

ii) Find and fit suitable ethernet switch to star to n raspberry pi boards per bench.
Report on cost and performance by comparison to having long ethernet cables from each.

It is not just IT which can find projects from the Raspberry Pi.

PS. Installing software is not so onerous. Cloning one good sd card with the password of the school is not too hard for a bright 12 year old to do from the worksheet, but I prefer a Linux PC for that which can do sudo dd ...

on a working rPi on internet and after startx, opening the terminal window and typing
sudo apt-get install abiword
sudo apt-get install gnumeric
results in half an hour of downloads and cpu activity, after which you have a wordprocessor and spreadsheet application, sufficient for example to write up a .pdf of something which can have a few charts and tables in it. Mine prints to the network printer but that configuration should probably be included on the school dd image.

Once you have a wordprocessor at every seat, typing class can move in.

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Re: USB peripherals, performance and power management

Mon Aug 27, 2012 5:44 am

If schools get the kit with the power supply as Gert had suggested above then schools should not need to splice a solution together.

I think primary students all ready get lots of time with a word processor. It would be. nice and in my opinion better if they used the raspberry pi to teach some python. I am not a primary school teacher but my gut tells new that python could possibly help students get more tuned into mathematics. The R-Pi together with the python interactive interpreter are a whole lot more dynamic than just a textbook and paper with pencil.

It would be so nice to see young people using a computer as a mathematical tool and not just as a word processor and social network tool.

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