Hi, I set up a LED light strip that is triggered by a PIR motion sensor (5v input) which is driven by an Ardiuno UNO R3. Both are powered by a 12V 30A Regulated power supply (the Arduino via the barrel jack).
When I have the Arduino plugged into my laptop everything runs perfectly. However, when I run everything through the power supply, the PIR motion seems to go into a detection loop (it seems to be cycling HIGH/LOW).
Any idea why the PIR behaves differently when my power source changes?
This is the style of sensor (it looks like it should be fine at 12v):
Did you connect the 12volt supply to the DC socket of the Uno.
Did you power the PIR sensor from the 5volt pin of the Uno.
Did you turn the 'time' pot full anti-clockwise (and leave the 'sensitivity' pot in the middle).
Timing needs to be controlled by the Uno, and that doesn't work if the 'time' pot is not on minimum.
What else is connected/powered by the Uno, apart from the mosfet to PWM the strip and the PIR.
The Uno can't supply more than ~100mA when powered from 12volt.
Anything over~150mA (temp dependent) will put the Uno through a reset/boot cycle (if you're lucky).
Leo..
Thanks for the reply. The project runs fine, except when powered by 12v.
Did you connect the 12volt supply to the DC socket of the Uno.
-Yes, it is connected to the barrel jack.
Did you power the PIR sensor from the 5volt pin of the Uno.
-Yes.
Did you turn the 'time' pot full anti-clockwise (and leave the 'sensitivity' pot in the middle).
Timing needs to be controlled by the Uno, and that doesn't work if the 'time' pot is not on minimum.
-My settings are good and responsive when it is being powered through the laptop usb power.
What else is connected/powered by the Uno, apart from the mosfet to PWM the strip and the PIR.
The Uno can't supply more than ~100mA when powered from 12volt.
Anything over~150mA (temp dependent) will put the Uno through a reset/boot cycle (if you're lucky).
-Interesting. There is nothing else attached other than the the things you've listed. It is not rebooting.