Hi all...I'm once again lookkng for some expertise...my project uses two ultrasonic sensors to detect movement, and trigger 12v led light strip. The lights are to remain on for 20 seconds, then go off. The cucuit is controlled by an arduino nano. I have the +12v from supply connected to the +12v input on lights. The output pin from the nano conbects to a uln2003 through a resistor, and ftom the 2003 to the -led connection. Everything worked perfect when using my atx power supply, but when using a 12v wall wart supply, the leds remain dimly lit when they should be off Can anyone explain why this is happening, and more importantly how ti remedy? Thank you!!
Show us a good schematic of your circuit. Show us a good image of your wiring.
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Its taken apart at the moment...trying to isklate ghe problem.I won't bd able to get back to it until Sunday...sorry. Iys alk breadboarded for now. Can yhe different power supply be the issue? I've tried researching online, but most posts aren't dealing with strips; they deal with bulbs having dimming problems...
ATX PS can deliver a lot more current than the ULN2003 through a wall wart.
Hi,
Do you have a DMM?
Check that the 12V Plugpack is really outputting 12V and not some much higher unregulated voltage.
Tom.... 
I did think of that, checked, and it was outputting higher than 12v. I put it on a dc-dc buck converter, adjusted it for 12v and used it for power, but made no difference...