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Author Topic: Power usage of Foscam FI8908/8918 and clones  (Read 23980 times)

April 04, 2011, 06:10:31 pm
Hopefully someone here knows the answer since I've failed to find it anywhere else.

What's the current draw of the IP cameras when they are idle - i.e. no network traffic (but still connected to WiFi), no motion detection, no LEDs, no pan, no tilt - just sitting there all lonely waiting for someone to talk to it?

I want to run the camera from a sealed lead acid battery via a 5v regulator to do some time lapse shots but don't know how long the battery will last.  Can anyone help me?

I had wondered about remotely turning it off/on when I'm not taking a picture but then I saw that the power up cycle does some kind of calibration which presumably looses the positioning - can this be disabled by firmware modification?  I just want to set the position and keep it there even if I have to power down the camera.

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April 05, 2011, 12:21:22 am
I'd say the wifi, ram and camera will be the main power draws - wifi  will typically be in the 200-800mw when in use, ram in the 1w range, and camera similar.

CPU is quite low power - less than 80ma (according to the datasheet), and we could also put it to sleep if needed - has a suspend mode, plus it also can disable unused peripherals.

You'll probably lose power more through the regulator, than from the cpu!
I wouldn't suggest power up / down, as it goes through a reboot each time (and some of the firmware's reset the camera position as you've noted).

I'd say probably going to be in the 4amp 1amp range, as ram and camera will be big draws.


Battery capacity (Ah) = Current drawn (I) x Time (H)
Time = Battery capacity / Current drawn
Current drawn = Battery capacity / Time

Lets assume 4000ma 1000ma current draw, with a 6v 10A battery.

Power (Watts) = Voltage of battery (V) x Current drawn in amps (I)

P = 6v x 1amp
So we'd be drawing roughly 6 watts of sheer power ;)

...and with a 10A / 1A = 10 hrs (+-2 less in real life due to losses).

So a 10A should give something like 8hrs, you can put them in series to give more amp hours.
Your average car battery 6v (most are 12v, but there are 6v, 12v and 24v available) is usually something in the 200Ah range though, so you'd get quite a bit more runtime!

My calculations may be completely off, but it should be in that kind of range, assuming my numbers are correct.

[Edited to correct for actual figures]
« Last Edit: April 05, 2011, 01:04:27 pm by admin »

April 05, 2011, 04:55:23 am
Hi,

Thanks for that.  I don't think that the total consumption will be 4A since the PSUs that ship are only 2A rating!  And the specs say that the power draw is 5W which only equates to 1A draw.

Is it possible for you or someone else here to measure the actual current draw?  I'm only really interested in draw when the unit is idle.

In an ideal world I'd be able to ask the s/w to shut down unwanted systems such as wired Ethernet, LEDs, pan/tilt, and even the CCD when I'm not asking the camera to take a picture.  Or am I simply living on another planet hoping for this? :-)

(I program on Linux for a living so am not too worried about changing software although I've not looked in detail at the various docs here and elsewhere on how to do this).


April 05, 2011, 10:37:42 am
Someone tested the power consumption (in all circumstance (moving, stable, with led on and off) with a physical tester on the forum here
http://forum.hardware.fr/hfr/HardwarePeripheriques/Webcam/fi8918w-visioncam-camhed02ipw-sujet_50586_1.htm
its in french but its in the last 5-10 pages i think u should go check its .jpg image

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April 05, 2011, 01:01:51 pm
Power Consumption from the post here - http://forum.hardware.fr/hfr/HardwarePeripheriques/Webcam/fi8918w-visioncam-camhed02ipw-sujet_50586_1.htm (Search for "SOLAIRE pour FOSCAM")

Juste pour Info – Relevé Conso Foscam FI8918W
Avec Watt mètre et Analyseur Turnigy (with watt meter & analyis of turning / moving).

->Avec sa prise secteur d’origine Basse tension
With the standard psu

Allumé (Lit)                 Tourne (Turning / Moving)
5,12V                    5,10V
2,8W                     4,0W
0,56A                    0,75A
 
->Sur batterie Solaire 12,6V avec Régulateur 5V 3A/5A (with Solar Battery 12, 6v + 5v 3a/5a regulator)
5,05V                    5,02V
2,1W                     3,6W           
0,43A                    0,72A     

April 05, 2011, 05:18:24 pm
So if I read that correctly, power draw is 560mA with the LEDs on.

Assuming 10-20mA per LED, there's up to 200mA of LED current there, so 400mA might be a reasonable estimate of the idle current?

I notice that in the programming/CGI spec, the Set_misc.cgi command has an option called Ptz_center_onstart, would I be correct in thinking that this disables the power on recalibration of the PTZ mechanism, and therefore would mean that a preset position would not be lost?

Thanks for the continuing help!

Andy

April 05, 2011, 07:53:27 pm

I notice that in the programming/CGI spec, the Set_misc.cgi command has an option called Ptz_center_onstart, would I be correct in thinking that this disables the power on recalibration of the PTZ mechanism, and therefore would mean that a preset position would not be lost?

That is correct. However, that's a new addition to the API and not all cameras support it.

April 06, 2011, 05:58:04 am

I notice that in the programming/CGI spec, the Set_misc.cgi command has an option called Ptz_center_onstart, would I be correct in thinking that this disables the power on recalibration of the PTZ mechanism, and therefore would mean that a preset position would not be lost?

That is correct. However, that's a new addition to the API and not all cameras support it.

Is this something added via a firmware version or specific to new cameras?  I'm looking at a Foscam (either 8908 or 8918 - not sure which yet), how can I tell if it will support this feature?

Thanks.

April 06, 2011, 06:52:33 am

I notice that in the programming/CGI spec, the Set_misc.cgi command has an option called Ptz_center_onstart, would I be correct in thinking that this disables the power on recalibration of the PTZ mechanism, and therefore would mean that a preset position would not be lost?

That is correct. However, that's a new addition to the API and not all cameras support it.

Is this something added via a firmware version or specific to new cameras?  I'm looking at a Foscam (either 8908 or 8918 - not sure which yet), how can I tell if it will support this feature?

Thanks.
It's a firmware revision.

April 26, 2011, 09:27:46 am
Just done some current measurements on my FI8918W camera:

  • During startup - 300-400mA
  • Post startup, having failed to join a WiFi network - 215mA
  • Post startup, connected to a WiFi network - 515mA
  • With web browser connection via WiFi, on configuration page - 515mA
  • Streaming picture to web browser (no audio) - 570mA
  • Streaming same picture to web browser, with IR LEDs on and ambient lights off - 680mA
  • Streaming black picture to web browser (no audio) - 530mA - presumably less WiFi frames because black compresses better?
  • Streaming picture to web browser, whilst panning - 850mA
  • Streaming picture to web browser, whilst tilting - 860mA

Hopefully this will be of use to someone...

April 28, 2011, 01:37:44 pm
I got my battery powered setup up and working, and nailed to a tree.

I had to buy a cheap 12v remote control http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290534512059 and control this with a microcontroller connected to my computer to turn the camera on and off when I want to take a picture, since the solar charger is only ~1.5W and the camera is about 3W.  I've got a 12v to 5v regulator in the box to step the battery voltage down for the camera.

(Note: if you buy one of the above remote control units, try to get a latching one instead of momentary one.  I find that sometimes the remote drops out, rebooting the camera, when the camera starts WiFi).

I'm currently taking one picture an hour - hopefully the solar charger can keep up with this - time will tell...
« Last Edit: April 28, 2011, 01:41:06 pm by ajuniper »

April 28, 2011, 02:30:37 pm
Nice. Are you watching the bird box for anything specific?


Is that a lm7805 attached to a makeshift heatsink? I hope the relay is between the battery and the 5v regulator, those things tend to waste power even when there is no load.
« Last Edit: April 28, 2011, 02:35:21 pm by Nocturnal »

April 28, 2011, 02:47:44 pm
We're just beginning a house extension and for fun I thought that I'd do a time lapse sequence of the build.  There's not much to see right now...

It is indeed a 7805 on a very makeshift heatsink but that's after the on/off relay.  The relay board takes about 6mA @ 12v when everything is off.  It only takes around a minute for the camera to power up and to retrieve the picture (controlled by script on Linux box) so the camera doesn't really run for long enough to warm the regulator anyway.

April 28, 2011, 03:38:38 pm
:) I'd love to see the finished sequence... I suspect its going to be a while though.

April 28, 2011, 03:46:41 pm
The current estimate is 4 months... I'll post a movie when there's something worth seeing...