msharma
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Raspberry Pi - camera, reducing power consumption

Tue Jun 28, 2016 10:01 am

Hi, I'm just starting a Raspberry Pi and am planning to use the model A+. I am planning to use a camera module. I was wondering whether there are any options to reduce its power consumption, I read that the current draw is 250mA, any way this could be reduced?

Furthermore, the camera's are generally connected using 15cm ribbon cables. I was wondering whether this distance could be extended without any loss in picture quality.

Thanks

jamesh
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Re: Raspberry Pi - camera, reducing power consumption

Tue Jun 28, 2016 10:16 am

Yes, you can extend the ribbon cable. There may be some degradation at larger distances due to signal loss, but its usually not too bad.

The camera takes about 200-250mA. There isn't anything you can do to change that. It's a large silicon die with lots of transistors on it, about 5 or 6 per pixel, plus other items like capacitors. That takes power and there is no way, AFAIK, of turning off chunk of the die. In fact, I suspect it's not physically possible to do.
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msharma
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Re: Raspberry Pi - camera, reducing power consumption

Tue Jun 28, 2016 10:17 am

What sort of distance do you think I could get on the ribbon cable? Ideally a few meters but I understand that this is very unfeasible, but I can't really think of an alternative.

Could I not drop the framerate on the camera to reduce power?


Thanks for your response!

jamesh
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Re: Raspberry Pi - camera, reducing power consumption

Tue Jun 28, 2016 10:26 am

msharma wrote:What sort of distance do you think I could get on the ribbon cable? Ideally a few meters but I understand that this is very unfeasible, but I can't really think of an alternative.

Could I not drop the framerate on the camera to reduce power?


Thanks for your response!
There is a thread in the camera forum talking about long cable lengths, Google should find it.

I don't think framerate has any influence on power consumption. The sensor is always working. But I could be wrong; if the readout is less frequent, it might use less power - you would need a camera HW expert to help out there.
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Re: Raspberry Pi - camera, reducing power consumption

Tue Jun 28, 2016 10:31 am

I found dropping resolution saves quite a bit of power

(recording in 720p instead of 1080 )

viewtopic.php?f=63&t=147687&start=25#p985213
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msharma
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Re: Raspberry Pi - camera, reducing power consumption

Tue Jun 28, 2016 10:33 am

mikerr wrote:I found dropping resolution saves quite a bit of power

(recording in 720p instead of 1080 )

viewtopic.php?f=63&t=147687&start=25#p985213
That is very good actually, thank you for that information!! I'm working on a project which is very sensitive to power consumption.

Ive also managed to find a forum post which extended the ribbon cable to 4m, and apparently it worked well. I'm not sure about this, it is likely that skew will be a big problem.

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pi-anazazi
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Re: Raspberry Pi - camera, reducing power consumption

Tue Jun 28, 2016 11:14 am

Hi!

I have a cam with a 2m cable and with fast (!) moving of the cam I saw some problems in the past that the films appeared some kind of "fragmented", however, with normal movement that should not be a problem.

Power saving: turn off video output? Turn off USB? There are some infos on this here on the formum ;-)
Kind regards

anazazi

msharma
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Re: Raspberry Pi - camera, reducing power consumption

Tue Jun 28, 2016 11:20 am

pi-anazazi wrote:Hi!

I have a cam with a 2m cable and with fast (!) moving of the cam I saw some problems in the past that the films appeared some kind of "fragmented", however, with normal movement that should not be a problem.

Power saving: turn off video output? Turn off USB? There are some infos on this here on the formum ;-)
Hi, the current plan is using the camera as a rear camera, car will be moving at maybe 50 mph. Is it speed or acceleration that seems to affect it? It is likely that images are quite ... stable.

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pi-anazazi
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Re: Raspberry Pi - camera, reducing power consumption

Tue Jun 28, 2016 11:26 am

Yeah, your picture should be quite stable, I guess.

I was moving at maybe 30-40 km/h, camera perspective was from approx. 16 m above, moving at a little higher speed...

Thought about your application, too. I would use the 12 V power supply in your car (there are USB-plugs for the car net, should give you 5V....) and put the cam in the car boot (short cam cable, maybe 1 m should work) ;-)
Kind regards

anazazi

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bensimmo
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Re: Raspberry Pi - camera, reducing power consumption

Fri Jul 01, 2016 6:58 am

To save power you turn it off when no in use in the programming, though you'll have a short delay when turning it back on.

Have you thought about locating the pi nearer the camera, if space is a problem then maybe the Zero could be used. They have a similar power usage.

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