Powering Camera

[Dan8118]

Hey there I was curious if I could pick someone's brain for my project.

I need to power a wireless network camera (http://mydlink.dlink.com/DCS930L) with a portable power source. The idea was to mount this camera on my RC Car.

The product manual says it uses 5V 1.2 A so i was thinking some rechargeable high power RC car batteries set up in a way to power the cam.

Any Ideas how to set up a portable power source like this?

[rbtying]

Get an RC battery with a nominal voltage of more than 7.2v or so, then pass it through a 5v BEC or other SMPS.  You will want to find another power connector for the camera, and then use a multimeter to make sure you're connecting things right.  If it's a barrel jack, you probably want center positive (but CHECK FIRST!). 

It's the same thing you'd do to power RC servos and receivers - just make sure your BEC can handle the current + some (3A would be perfect).

[Dan8118]

Thank you so much for the help about the camera power supply. I hate acting like I cant use google my self but this is the first time doing anything of this nature.

Any way you could assemble a part list with links. I know this is a crazy request but I'm working with a budget for my class project and I'm just afraid to make useless purchases.

Thank you,
-Dan

[Soeren]

The 1.2A may be a max. specification with the average draw being lower - what exactly does the manual say?

Just make the shopping list yourself and post it here for review - it's much better training for you (and less work for others - showing initiative in own projects is the sure fire way of getting others interested in helping).

[Dan8118]

1.2 Amps is whats coming out of the wall AC adapter so i assume i have to mimic that. Im afraid i dont know where to start when trying to come up with a parts list.

[Soeren]

Hi,

1.2 Amps is whats coming out of the wall AC adapter so i assume i have to mimic that. Im afraid i dont know where to start when trying to come up with a parts list.

No.
No current "is coming out of the wall AC adapter".
Current is drawn out by a connected load.
This is a very important difference, whether you realize it or not.

How did you determine the 1.2A?
Was it "The product manual says it uses 5V 1.2 A"?
You need to be certain of both the average current and the max. peak current needed by the cam before making an optimum regulator as cheap as possible.

[Dan8118]

The user manual says:

POWER:

• Input: 100-240 V AC, 50/60 Hz
• Output: 5 V DC, 1.2 A
• External AC-to-DC switching power adapter

MAX POWER CONSUMPTION:
2W

[waltr]

MAX POWER CONSUMPTION:
2W

2W / 5V = 400mA

[Dan8118]

I guess i misunderstood the user's manual... Any thoughts on what ill need?

[Soeren]

Hi,

I guess i misunderstood the user's manual... Any thoughts on what ill need?

The manual is lying, pure and simple.

If the cam is doing fine on 400mA, use MIC2940 to regulate from either a 6 cell NiMH battery or a 2 cell lithium battery.

The MIC2940 (not LM2940, the drop out of the LM-version is too large!!) should have a 220nF capacitor from its input terminal to its ground terminal and 2 x 10µF from its output terminal to the ground terminal. Don't use 1 x 22µF on the output, but 2 x 10µF, as the purpose is to lower the ESR. Place the capacitors as close to the LDO terminals as possible (without overdoing it).

Use a 500mA Slow-Blow fuse between B+ (the positive side of the battery) and the input of the LDO, as close as possible to the battery.
A switch in between the fuse and the LDO is probably a good thing too

When assembled, measure the voltage before connecting the cam to assure there's 5V out.

[Dan8118]

Thank you so much I am really greatful of the time spent.

So this is what im looking at

Battery- Do i Want 7.2 V ? - http://www.amazon.com/6-Cell-7-2V-1800mAh-NiCd-Battery/dp/B0006N6XA2/ref=sr_1_2?s=toys-and-games&ie=UTF8&qid=1301206398&sr=1-2

Regulator http://www.futureelectronics.com/en/Search.aspx?dsNav=Ntk:PartNumberSearch%7cMIC2940A%2f-5.0WT%7c1%7c,Ny:True,Nea:True,N:4294938435

The other supplies I should be able to find in my school lab. Those parts look right?

[Soeren]

Seems fine.
However, Amazon is expensive, so take a look at http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXXUP0&P=ML where you get more runtime for the same money. Look around their battery section and you will find 6-cell/1800mAh around 25% cheaper and you can get a 6-cell/1500mAh at around $10.

[Dan8118]

Thanks for all the help....ordered the parts today ill let you know how it goes.