Page 7 of 7

Re: Why is the PI2 camera-shy ?

Posted: Mon Feb 09, 2015 8:42 pm
by gordon77
joan wrote:I skimmed the thread. Apologies if this has already been posted a dozen times.

http://www.bbc.co.uk/news/technology-31294745
I think eben sets the correct level with stick blutac on it :D

Re: Why is the PI2 camera-shy ?

Posted: Mon Feb 09, 2015 8:51 pm
by DougieLawson
simpex wrote:
I believe that a lot o light sources, that people use at home or in labs, can reset Raspberry Pi 2 if they are positioned less than 20 cm away from the board.
OK, so where's your simple experiment, where's your empirical evidence? Where's the details of how I can repeat your tests and prove or disprove them?

I think I've just repeated what Clive from the RPF asked you.

Re: Why is the PI2 camera-shy ?

Posted: Mon Feb 09, 2015 9:22 pm
by shaz
I think I corrupted my SD card as it rebooted when taking a picture.

Now I cannot read the SD card from my laptop and the ACT light on the Pi 2.0 remains stable instead of blinking, without any video appearing / booting.

Is there anything I can do?

Re: Why is the PI2 camera-shy ?

Posted: Mon Feb 09, 2015 9:35 pm
by jdb
shaz wrote:I think I corrupted my SD card as it rebooted when taking a picture.

Now I cannot read the SD card from my laptop and the ACT light on the Pi 2.0 remains stable instead of blinking, without any video appearing / booting.

Is there anything I can do?
The warning in today's blog post was for this very reason...

Most likely the flash went off while the filesystem was being written to, corrupting it. It would be equivalent to pulling the plug on the Pi's power, which is the number one reason for corrupting SD cards.

Use the SD Association formatting tool and see if you can reformat the card. If you can, then re-image it in the usual way.

Re: Why is the PI2 camera-shy ?

Posted: Mon Feb 09, 2015 9:37 pm
by rurwin
If anyone is interested in the chip markings:

Image

Re: Why is the PI2 camera-shy ?

Posted: Mon Feb 09, 2015 10:14 pm
by g7ruh
Nobody has mentioned thunderstorms (I think). Lightning is rather bright and I suspect will trigger this event. We shall see if we get reports of sulking pi after a thunderstorm. Bit hard to test in the UK in winter.

Re: Why is the PI2 camera-shy ?

Posted: Mon Feb 09, 2015 10:30 pm
by jamesh
simpex wrote:
jamesh wrote:Speed of moving the dot is irrelevant - the point is that as the dot hits the edge, there is an instant increase in light (providing it's a decent laser). One moment unlit, next moment lit.
Speed is relevant because the laser dot does not present a constant intensity across its entire surface. The edges of the spot have close to zero intensities while the center reaches the maximum. As the red dot comes closer to the IC that causes the glitch, more and more light illuminates the circuit. So, that U16 (I hope U16 is the real culprit) is gradually illuminated by the laser dot.

What exactly do you see on the oscilloscope when a laser dot is switched on, pointed a few inches away from U16 and then moved above U16?
Laser's should by definition not diverge at al. So they should have the same intensity across the entire dot. However, LED lasers are a bit rubbish and will have an intensity change, but not a huge effect and the dot is so small, that the speed of the passing should make very little difference. You would also need to be moving the dot extremely accurately and extremely slowly (more accurately and slowly than you could hold the laser)

Re: Why is the PI2 camera-shy ?

Posted: Mon Feb 09, 2015 10:32 pm
by simpex
clive wrote:
simpex wrote:Raspberry Pi 2 can easily come close to a halogen lamp (http://www.homedepot.ca/catalog/halogen-bulbs/172459) that likely will cause it to either freeze or reset...
You might want to test your data-surmised hypothesis. By shining one of those lights on a Pi 2 for example
Luckily, I do not have a Raspberry Pi 2 so I can just ask somebody who already bought one, it could be the topic opener, Peter O., to illuminate his board with a halogen lamp and see what happens.

Re: Why is the PI2 camera-shy ?

Posted: Mon Feb 09, 2015 10:39 pm
by simpex
jamesh wrote:Laser's should by definition not diverge at al. So they should have the same intensity across the entire dot
A Gaussian beam emitted by a Helium-Neon laser hitting a screen.
Image

Re: Why is the PI2 camera-shy ?

Posted: Mon Feb 09, 2015 10:41 pm
by Lob0426
rahlquist wrote:
Lob0426 wrote:How many of us are going to be taking pictures, shining Lasers or any other bright source, on operating RasPii, now that we know there could be an issue? I am putting mine into a case.
You make valid points but I believe everyone is just trying to make sure its figured out and everyone wants to contribute. A case may fix 99% of issues but most of us like better than 99% reliability if we can manage it I am sure. In my case the primary use for some of my Pi is in part as IP cameras. Some of the cameras do face roadways and I need to know that some person with 2M candlepower Xenon headlamps, light bars, whatever is not going to catch my Pi and poke it in the eye on the way by. ;)

So, yes, for a lot of us who dwell in an evil lair, poorly lit, with no bright corona or xenon or laser discharge it's a non starter of an issue ;) For others we just want to understand and fix, to prevent the 1% random error from this item.
I just felt some people were on the border of concern trolling!
Those that are trying to diagnose the issue are not the people I was talking to.

Those of us under the bridge trolls will be unlikely to have the problem at all!

LOL. Well if they have 2 million candlepower lights here in the Peoples Republic of Californica, They will get ticketed.

Re: Why is the PI2 camera-shy ?

Posted: Mon Feb 09, 2015 11:29 pm
by liz
g7ruh wrote:Nobody has mentioned thunderstorms (I think). Lightning is rather bright and I suspect will trigger this event. We shall see if we get reports of sulking pi after a thunderstorm. Bit hard to test in the UK in winter.
That bit in the blogpost where we were talking about wavelengths and intensity? Lightning is definitely not going to trigger this event.

Re: Why is the PI2 camera-shy ?

Posted: Mon Feb 09, 2015 11:31 pm
by liz
simpex wrote:
clive wrote:
simpex wrote:Raspberry Pi 2 can easily come close to a halogen lamp (http://www.homedepot.ca/catalog/halogen-bulbs/172459) that likely will cause it to either freeze or reset...
You might want to test your data-surmised hypothesis. By shining one of those lights on a Pi 2 for example
Luckily, I do not have a Raspberry Pi 2 so I can just ask somebody who already bought one, it could be the topic opener, Peter O., to illuminate his board with a halogen lamp and see what happens.
We have one in the office. Nothing happens. Really - PLEASE read the blog post I wrote today; this is all covered there.

Closing this thread now; we can all do without the conspiracy theories! For the definitive word on this, please see:

http://www.raspberrypi.org/xenon-death- ... cs-lesson/

Re: Why is the PI2 camera-shy ?

Posted: Tue Feb 10, 2015 12:09 am
by clive
Handy science tip if people are going to discuss this elsewhere on the forum -- "I think this..." and "I believe that..." statements in this context are like claiming that you can open a tin of beans by shouting at it in Klingon: a bit weird but so easy to (dis)prove that unless you provide some evidence no one will take you seriously.