Jun 09, 2012 · Raspberry Pi GPIO Layout – Pi 1 Model B Revision 1 The Pin marked “P1” is Pin 1 and provides 3.3V (50mA max). You can work out all the other pins from there. Aug 12, 2016 · So instead, I am now using a GPIO pin (3.3V) as the source of power for the four sensors. When my application detects the sensors have vanished I switch OFF the GPIO pin to power down the sensors for 20 seconds and then switch the GPIO pin back on. The sensors re-appear. A GPIO pin can supply enough current at 3.3V to power my four sensors.

Actually , the default state of the gpio pins on the Raspberry PI are 'input' , which is 'correct' logic. The pine board is not consistent in this regard. It may be possible to set the default state in dts|dtb , but I have not looked into it yet seriously; although , I am not at all hopeful. Lots of articles are available to tell you how to use a breadboard to connect a button or LED to a Raspberry Pi’s GPIO pins. This article focuses on doing something useful with those switches and LEDs. The safe off-switch is complementary to a reset switch, which is the best method for starting the Raspberry Pi up again.