loheiman
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Advice for a portable, battery powered Pi camera

Sun Sep 07, 2014 9:35 pm

Hi!

I've been wanting to play around with a Raspberry Pi and thought a battery powered Pi camera might be a great way to do that. I'd like the Pi to livestream its video (in HD if possible) as well as take periodic stills and upload to a server. I'm also toying with the idea of mounting to my cat (but understand that this may or may not be a good idea...)

I plan on attaching the Pi Camera Module and a mini WiFi adapter via USB and then shutting off all other peripherals/ports. The Pi will be powered by a 5V output portable battery pack.

Questions:
Should I go with the Model A or B+? I think power consumption would be the main consideration here but I can't find any conclusive data that compares the two (Some say the Model A uses 1/3 the power of the Model B with the Model B+ using about 2/3 the power?)
What sort of power consumption should I be expecting with the camera module taking HD video and livestreaming it over WiFi? ~2 watts?
Assuming the power draw is ~2 watts, with a 5000mah battery pack (built around a 3.7V battery I assume, making it 18.5whr), would be that enough for about 8 hours of battery life?

Thanks in advance!
Last edited by loheiman on Mon Sep 08, 2014 4:45 pm, edited 2 times in total.

drgeoff
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Re: Suggestions for cat-mounted pi-powered video camera!

Sun Sep 07, 2014 11:42 pm

Our 8.5 kg cat is at the upper end of the size and weight ranges for a domestic moggie. I cannot envisage him accepting what you propose attached to his back.

fruitoftheloom
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Re: Suggestions for cat-mounted pi-powered video camera!

Mon Sep 08, 2014 6:17 am

Call the RSPCA :shock:
Retired disgracefully.....

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RaTTuS
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Re: Suggestions for cat-mounted pi-powered video camera!

Mon Sep 08, 2014 8:27 am

it would last about 5 mins and you will lose the parts ;)
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PiGraham
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Re: Suggestions for cat-mounted pi-powered video camera!

Mon Sep 08, 2014 10:25 am

The Raspberry Pi i snot suitable for this. You prime concrn should be the welfare of the cat(s).

Read about how professionals put tracking cameras on cats for the BBC Horizon program The Secret Life of the Cat

In particular note the size and position of the camera and pay attention to this bit :
The collars used 'breakaway' safety buckles so that they would pop off if it got snagged in a hedgerow.

Ravenous
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Re: Suggestions for cat-mounted pi-powered video camera!

Mon Sep 08, 2014 12:23 pm

If you want something safer (for the cat and the hardware), there have been raspi projects like automated cat feeders, with or without a camera to photograph moggy each feeding time. At least with a fixed unit you wouldn't have to worry about battery size/life. :?:

Twinkletoes
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Re: Suggestions for cat-mounted pi-powered video camera!

Mon Sep 08, 2014 4:23 pm

I'm seeing about 5 watts with pi model B with wifi.

loheiman
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Re: Suggestions for cat-mounted pi-powered video camera!

Mon Sep 08, 2014 4:44 pm

I hear you guys regarding the bulk and safety of doing this. I may not actually mount this to my cat but would still like to make this camera portable. (i've changed the title of this thread to reflect that)

With that said, do you advice regarding the power consumption? Thanks

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MattHawkinsUK
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Re: Advice for a portable, battery powered Pi camera

Mon Sep 08, 2014 6:27 pm

I think 8 hours would be pushing it with a 5000mAh battery. I would estimate 6-7 hours. The current draw on a B+ would be about 475mA with WiFi and the camera running.

I based this on my Android app "Pi Power Estimator" :)

As for cats the Pi, camera and battery is far too heavy and bulky. Downgrade your cat to a dog and it might work out.
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Burngate
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Re: Advice for a portable, battery powered Pi camera

Tue Sep 09, 2014 9:06 am

MattHawkinsUK wrote:As for cats the Pi, camera and battery is far too heavy and bulky.
Surely that depends on the breed? I doubt a Panthera tigris would notice it, though the initial installation might be risky.

Ravenous
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Re: Advice for a portable, battery powered Pi camera

Tue Sep 09, 2014 9:13 am

Burngate wrote:Surely that depends on the breed? I doubt a Panthera tigris would notice it, though the initial installation might be risky.
Somehow I doubt he has that particular cat... a bit heavy on the carpet...

To make a suggestion, for battery life estimates simply build a fixed prototype first, then get a cheap ammeter (1 amp range or so) and put it in series and actually measure what you get. Matt's suggestion above looks a good one but you'll never know until you try it with the gear you have.

A few people have posted about their own wildlife cameras/trail cameras so it should be possible to get a reasonable run time out of a portable box.

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