Testing 5v USB charger?

Using Arduino Project Guidance
1

Hi all

I'm very new to arduino, so i'm sorry if this is not the right place to place this post.

Because of another project i would like to test some 5v usb chargers with a arduino due board. I think i can put the 5v in analog pin 0 and connect the ground to the same ground as the board.

But i'm not sure if this works well, or if i need to put some resistances in it. Some usb charger gives 500 mA and others give 2000 mA.

I've seen some circuits where batteries were used but i don't know if they aply here...

Can you give some tips or point me somewhere else?

Thanks

Ricardo

2

The Arduino Due board runs at 3.3V. The maximum voltage that the I/O pins can tolerate is 3.3V. Applying voltages higher than 3.3V to any I/O pin could damage the board.

use voltage divider.

3

Ok, so i connect the 5v to a voltage divider and assume 3.3 volts instead of 5v, right?

4

Correct.

5

Thanks

6

However a faulty charger giving over 5V would also damage your Arduinio. Better to use catching diodes on each rail.

7

How do i do that???

8

Hi,

I suggest just buying one of these:
http://www.ebay.com/itm/USB-Volt-Current-Voltage-Doctor-Charger-Capacity-Tester-Meter-Power-Bank-EF-/231726191264?hash=item35f3f512a0:g:-fMAAOSwcBhWXYiO

or:
http://www.ebay.com/itm/USB-Charger-Doctor-Voltage-Current-Meter-Mobile-Battery-Tester-Power-Detector-Bl-/310983755607?hash=item4868138757:g:HTQAAOSwk5FUvciM

9

I don't think it gives much more than 5v. It's just that it can have too much noise and the rfm12B module starts to act funny.

I've been told the 5v charger can have great variations and mess everything. And there's a program someone made to check the deviation but no description on the connections to the 5v charger.

10

rjsc2000:
How do i do that???

Google
Catcher diodes.

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