Arduino not working when given alternate power.

Other Hardware General Electronics
1

I have a 2 button midi controller built and it works great when the arduino is connected to the host computer from which I drew the sketch from. As soon as I connect power from anywhere else other than my laptop I cannot get anything to work or a get some much signal interference through the the midi cable it's unreadble. Please help. These are the combinations I have tried.

USB power from laptop (which sketch was uploaded) works great

USB power from desktop- sends signal interference through midi cable

12v wall wart power supply,Center postive- only turns on lights no signal sent

9v lithium battery- same result as wall warr

Anybody have any ideas other than powering it thru my laptop.

2

So no sketch or schematics !

Any chance you can add them for others to be able to actually SEE what you have ?
It would make giving you any help so much easier.

Maybe also READ THIS.

3

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html
Where are you connecting the 9V and wall wart to on the Arduino?

What model Arduino are you using?

Thanks.. Tom... :slight_smile:

4

Seems to be a continuation of this post.
Leo..

5

GRRR !