Hi,

I need a little help with a project I am working on.

I have this camera mounted on my motorcycle helmet leading to this DVR recorder in one of my panniers.

The camera has a power draw of 50ma at 12v and the DVR unit draws 2a at 5v.

I need a power supply that can supply 12v and 5v from 8 AA batteries, that will automatically cut off if the battery voltage drops below a level that can sustain the 12 and 5 volt outputs.

Can anyony help me design this power supply or point me to a similar project.

Thanks,
Biggins

 

Well, eight AA alkaline batteries supply 12v under light load when they are brand new. That would work for your camera, but not for your DVR.

Here's a Design Note from Linear Devices on building a 5v 2a "buck" converter using one of their integrated regulators and a few external components:
http://cds.linear.com/docs/Design Note/dn412f.pdf

You could operate the DVR directly from your motorcycle's electrical system using that buck converter.