Need for R-Pi 'user guide'

[hippy]

I don't know if the Foundation or licensees have got this covered but there seems to be a number of people considering plugging their R-Pi computers into USB sockets of set-top boxes, TV's, wallwart power supplies and anything else that has one and not everyone understands the potential consequences of doing that.

It would be sensible for it to be clearly stated that it is the user's responsibility to ensure that the device plugged into can supply the current the R-Pi computer requires and any damage to that equipment is the sole responsibility of the user.

Ideally this should be prominently included in some 'user guide' which accompanies R-Pi computer delivery or I am sure we will see someone suing the Foundation for damage caused to their equipment because they were not explicitly warned such damage could occur. The negative headlines, should that happen, will do the R-Pi no favours.

[Ravenous]

I do foresee a lot of people blowing raspberries, as it were.  (At least there'll be lots of dead ones available for all these case designers, though even these will fetch a ton on the dreaded auction site.)

I also shudder to think of the logistics of producing 10,000 quick start guides (even a single page, in English).

At this stage as the buyers found them online and bought them online, so the Pictorial buying Guide or something on the wiki should be good enough - I hope...

[hippy]

Ravenous said:

At this stage as the buyers found them online and bought them online, so the Pictorial buying Guide or something on the wiki should be good enough - I hope...
Unfortunately those who have damaged anything and their lawyers will argue that's not so, consumers shouldn't be expected to go and hunt down essential information related to a product they purchased, and consumer protection laws often agree with that view.

The usual defence to liability claims is, 'you got a user guide telling you not to do what you did staring you in the face; you cannot miss it'. In the absence of that a defence becomes weaker and less certain.

The 'it's a developer board' defence also doesn't fly unless purchasers are informed of that and it is explicitly sold as such, and one probably has to explain what 'developer board' means if you expect consumers to understand that term.

It is a nightmare dealing with the general public and protecting oneself from whatever 'stupidity' they may indulge in but that's part and parcel of selling to the public.

[abishur]

In light of the forcing of the CE testing, I've gotta agree that a "it is a developer board" defense won't fly either.

So why don't we make one?

What do you think needs to go into a user guide?  For me I expect a couple points

1) Black and white.  Color costs a lot so a basic user-guide is either multiple pages of black and white or a single page of color at most

2) Cover page (Something like user's guide or getting started guide), Welcome page (short explanation of what the R-pi is and who the RPF are), Table of contents

3) Warnings (repetitive motions, ESD, bare board live (low) voltages)

4) Step by Step instructions for connecting it to TV/monitor

5) Certifications page maybe some more legal disclaimers (things that would never happen, but get put in the book all the same as a legal butt covering move)

[colincoach]

Abishur said:


In light of the forcing of the CE testing, I've gotta agree that a "it is a developer board" defense won't fly either.

So why don't we make one?

What do you think needs to go into a user guide?  For me I expect a couple points

1) Black and white.  Color costs a lot so a basic user-guide is either multiple pages of black and white or a single page of color at most

2) Cover page (Something like user's guide or getting started guide), Welcome page (short explanation of what the R-pi is and who the RPF are), Table of contents

3) Warnings (repetitive motions, ESD, bare board live (low) voltages)

4) Step by Step instructions for connecting it to TV/monitor

5) Certifications page maybe some more legal disclaimers (things that would never happen, but get put in the book all the same as a legal butt covering move)


Great proactive/can-do approach you are taking with this.

[hippy]

Most guides usually start with something like "do not connect anything until you have read and fully understood this guide" on the cover, often also a sticker on the board or board's packaging to say read the manual first, as that's the catch-all for any claims.

Most guides start with a list of warnings, cautions, safety advice, Do's and Do Not's, compliance sattements.

A diagram explaining the parts of the board.

The how to connect stuff.

The how to use stuff.

A TV, VCR, DVD or Hi-Fi user guide should give a general idea of what's required. My 'bog standard' £20 watch came with a credit card sized manual an inch thick. Only (!) 50 pages or so in English.

[liz]

We've got it covered.

[jojopi]

hippy said:

It would be sensible for it to be clearly stated that it is the user's responsibility to ensure that the device plugged into can supply the current the R-Pi computer requires and any damage to that equipment is the sole responsibility of the user.
Any host or charger that is damaged by trying to draw 700mA is absolute junk, however.  It is a reasonable value to expect and over-current protection is mandatory in the USB specification.

[peterpi]

hippy said:


people considering plugging their R-Pi computers into USB sockets of set-top boxes, TV's, wallwart power supplies and anything else that has one and not everyone understands the potential consequences of doing that.


I was intending on plugging my Pi into my monitor's USB sockets.  I currently do this for power and debugging when I'm coding for my android phone.  Will it make my Pi go Pop?

[abishur]

peterpi said:


hippy said:


people considering plugging their R-Pi computers into USB sockets of set-top boxes, TV's, wallwart power supplies and anything else that has one and not everyone understands the potential consequences of doing that.


I was intending on plugging my Pi into my monitor's USB sockets.  I currently do this for power and debugging when I'm coding for my android phone.  Will it make my Pi go Pop?



To be fair, the R-pi does have a voltage clamp that will lock down on anything above 5v and a self-resetting fuse that will pop on any current greater than 1 amp.  So the likelihood of damaging your Pi is low.  The issue with your USB sockets will be "can they provide enough current" assuming they can give 500mA then you should be able to power the pi off one of the ports provided you don't hook up a USB device.  If you get a Y cable to use both ports, then you'll have more than enough power to run the R-pi model B.

[Chris.Rowland]

AIUI the USB specification is for a maximum of 500 mA and even that requires some sort of negotiation. That's not enough to reliable run the Pi, especially as it does no power negotiation and may not get even that.

I don't think that supplying too little power will damage the Pi, it just won't work or if you are unlucky partially work but be terribly unreliable.

[Montala]

liz said:


We've got it covered.


That sounds encouraging Liz... do you have any (rough!) idea as to when it will be available yet?

Thanks!

[jojopi]

Chris Rowland said:


AIUI the USB specification is for a maximum of 500 mA and even that requires some sort of negotiation.


True, but have you ever seen a host or hub that includes the extra components that would be necessary to restrict the current until after the negotiation?  Most just have a 1A PPTC shared between each pair of ports.

[Joe Schmoe]

@Chris#11:

(echoing what you said)

I don't think the issue is frying the Pi.  As you state, that should be covered.

The problem is frying (or worse - see below) the thing supplying power.  I.e., if the thing supplying power is expecting to supply no more than 500ma (or less - e.g. that pin on the HDMI connector) and you try to draw more than that.  As mentioned above, this isn't supposed to be happen, but it probably will (especially likely if alcohol is involved).

And, in a worse case, it might burn your house down (here again, especially if alcohol is involved).

[rmm200]

I am sure many folks who have a perfectly good wall outlet will just plug it into that.

Could be a whole new Darwin Award category.

[Jim Manley]

"Your honor and ladies and gentlemen of the jury, there was no warning that my client"s dearly departed loving husband shouldn"t have placed the hazardous Ricebury Pie between his legs when it was plugged into a jury-rigged cigarette lighter power adapter, while buying a scalding hot cup of coffee at the fast food drive-thru. His poor children will never get to spend time with him when he would have driven across flooded roads, climbed high-voltage power distribution towers, attached rocket motors to his car to see how fast it would go on a straight road with a sudden turn a mile down, and all of the other things a fine, upstanding man will do just once in his lifetime, however brief it is otherwise naturally meant to be. I sincerely hope that you will see how evil this giant Ricebury Pie international conglomerate really is, and will award me, I mean my client, at least $100,000,000 in compensation for her and children"s pain and suffering, and to ensure the children can attend Harvard University from undergraduate studies through its prestigious School of Law. Thank you."