Hi, I think I know the answer, but want to confirm with experts here.
I have a Nano with a PIR sensor (HC-SR501) and a 5M RGB LED strip. The PIR is rated at operating 4.5V - 20V, and the RGB LED strip is rated at 12V. I've been using a 12V power supply to the VIN (8 AA batteries in a series), and I noticed the LEDs don't seem to light up well. By that, I mean I noticed that the Blue doesn't like to light up if the Red and Green are on. I just came to the realization that it could be that my 12V power supply is not enough since I didn't take the PIR power needs into account.
Is my math correct in that I would then need a 16.5V minimum + an extra 5V for the Nano to power my project? Am I underpowering this project?
The voltage must be 12V but the power supply has to be able to supply the current the circuit needs. If it can't then the 12V will drop to a lower value. But you must NOT increase the voltage to compensate you must get a supply with more current capability.
dlee83:
I just came to the realization that it could be that my 12V power supply is not enough since I didn't take the PIR power needs into account.
The PIR typically uses <100uA (nothing).
The Nano maybe 30-40mA.
But the LED strip itself could draw >5Amp.
Waaay to much for a set of batteries.
The battery voltage will collapse, and the LEDs with the highest forward voltage will stop working.
The red LEDs have a lower forward voltage, so will stay on the longest.
Don't raise the voltage. CURRENT is the problem.
Get a 12volt/5Amp mains supply.
Leo..
