i have this wifi camera: http://foscam.us/products/foscam-fi9821w-megapixel-wireless-ip-camera.html
I would have liked to have powered it either through the 5v output of raspberry, but i quickly learned that that would not work.
Now the specs aren't clear on the voltage or amps that it draws..but the dc adapter that it came with outputs 5v/2amps, so i figured at minimum i needed a power supply that does the same.
So i figured that at least one of these two supplies would work (i use them to power by raspberry fine):
I tried them with the foscam camera being sure that i used one of the usb ports that outputs atleast 5v and at least 2amps. It doesn't work. BUT, When i use a 7.2V nimh battery however, it does work! I'm totally confused...
Can anyone explain what is going on here? the camera works with a dc wall adapter that outputs 5v/2am, but doesn't work a charager that does the same. why?
I would say the supply that fails to work is not managing to offer the full 5v or maybe not enough current. I did a quick bit more searching, and, the only information I found was in line with what you stated; 5v @ 2A and a max of 5W. The only thing I can suggest is that you put a meter on the output of your supplies, and, make sure they are actually offering 5v. It would be better if you could manage to put a load on it to make sure the voltage doesn’t drop when the supply is made to do some actual work.
I had checked the voltage of the supply that did not work and recall it was between 4.8 and 4.9v for the two. When I checked the voltage of the dc wall adapter(which worked fine), the voltage was at around 5.18v. Do you think this small difference in voltage could cause this?
So i put two 470uf in parrallel, connect the battery and the reading is 5.12 V. When connected to the camera though, it’s 4.43v. I’m guessing i need something a littler higher than 5v to compensate for this drop?
You guys are right as always…i ended up powering the camera from the battery i used for my motor w/ a ubec 5v/3amp step down converter and works fine…cept for the part where the wires and bread board started to melt cause the motors were drawing too much current (i think the robot is a bit too heavy for these motors).
