Hardware: Powering the Pi
The Pi, scale. and other sensors require 5 VDC and can be powered several ways. 5 VDC can be supplied from a AC mains adapter, an automotive 12 VDC USB adapter, or the power supply on the Hive Interface board.
Warning: It is important to only use one power source at a time. For example, do not power the Pi through the Micro USB power connector from one power supply and through the USB console cable from another power supply. The two power supplies may fight each other and burn up!
Micro USB power connector on the Pi
This is the safest way to power the system. A USB Type A Male to USB Micro B Male cable plugged into the power connector on the Pi. This is the preferred method as the pico fuse on the Pi board is used. The other end of the Micro USB cable can be plugged into a USB power supply like a cell phone charger, a powered USB hub, or a USB port on a computer.
TTL/USB conversion cable
Through the USB console cable. This is handy for testing and development as the system can be powered from the USB port of another computer. Plug the cable into H4 on the interface board in this order: Red, White, Green, Black.
Back feed through the Pi's USB port
Back feed through the Pi's USB port with a special USB Type A Male to USB Type A Male cable.
- The pico fuse is bypassed.
- This cable violates and defeats the USB standard.
- The USB Type A to Type A cable is dangerous to have around. Do not use it to connect two powered devices, such as two laptops, together.
12 VDC supply on the Hive Interface board
This is not recommended unless you know what you are doing as you can blow up the whole kit if you are not careful. See Hardware: Hive Interface Board 0.3#Power Supplies for details.