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Topic: Arduino is fine when connected to computer but not when on battery (Read 2165 times) previous topic - next topic


Mar 05, 2012, 02:57 am Last Edit: Mar 05, 2012, 03:05 am by Techone Reason: 1
Fine... what the DVM is saying to you ? Measurment of the voltage of the 9 V battery.

Edit :

Here what I did.   I have an Arduino with just the board and the blink program running.

With power off : 9.39 V  Connect to the board : 8.80 V and going down by the seconds.

What is your ?


Just running the board, the type of regulator used wastes tons of power.
I would suggest just putting 3 X AA into the 5v pin.
Avoid throwing electronics out as you or someone else might need them for parts or use.
Solid state rectifiers are the only REAL rectifiers.
Resistors for LEDS!


i thought it was 5.5v output only...

call me stupid (on this occasion you can :-P) but surly its output only and not input? and i would need to earth it too?


but surly its output only and not input? and i would need to earth it too?

The +5 V pin is the input voltage OR output voltage.   Huh ? 

OK...When you connect a external voltage <--- USB or through the barrel, that +5 V is OUTPUT. 

Whith nothing external connected, Well the +5 V is an INPUT. That is when you put a 4.5 V in ( 3 X AA or C or D ). A 4.5 V will work. I try it on a breadboard version.

And of course you must connect the negative to the GND of the Arduino, same of the battery controlling the servo motor.

FYI.  I did some current measurement of a servo motor. I use two type of servo. One normal servo and one for continous turn. The current for a continious is : about 160 mA.  and the normal servo : from 50 mA ( slowest ) to 200 mA ( fastest ) And my Arduino board with a 9 V battery, the current is about 40 mA. <-- That is no Led's, no shields, nothing connected except the control logic of the servo motor.

In your case, I am curious what type of current and voltage measurements ( at the barrel ) when you connect the 9 V battery.


Well, I've connected an LED between the CS on the receiver and the GND and it seems to be working now...

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