I googled it and failed to find definitive answers for this. Would you help me plz?
I'd like to make a smartphone-powered LED.
When I made a system like below, it didn't work.
(1) 30 pin to USB connector is connected to iphone 4
(2) Pin 1st (USB 5V) and Pin 4th (GND) of USB connector is connected to a LED by soldering.
But I could not see any emission.