Whether you use a desktop or a laptop computer, one of its features is the intelligent power supply that shuts down the system once it detects that the software has sent the shutdown command. To switch the system on, you need only press a small button. The Raspberry Pi, or the RBPi, being a low-cost single board computer, does not have this feature. After shutting down the OS, you have to unplug the power cable physically from the RBPi.
With large numbers of community projects springing up around the credit-card sized SBC, the RBPi can also enjoy the features of an intelligent power supply. This is the Pi Supply project, which sits between the actual power supply and the RBPi, adding its own intelligence as necessary. Pi Supply takes its power from the micro-USB charger and powers the RBPi.
When the RBPi issues a ‘sudo halt’ command, Pi Supply detects the shutdown command and switches off the power to the SBC at a safe moment. To switch the power back on, simply press a button on the Pi Supply, and your RBPi springs back to life. You do not need to plug/unplug the micro-USB connector anymore. With power supply issues being one of the biggest headaches for SD card corruption, the Pi Supply is a very handy project.
The Pi Supply provides a single window solution to all the power management problems your RBPi currently faces. This intelligent ATX style power supply switch is a revolutionary solution for the RBPi, since you do not need to disconnect any power supply wire from the wall-wart to the RBPi. Turning power on/off to the RBPi is now possible simply by touching one of the two buttons on the Pi Supply.
Once your work with the RBPi is over, you simply issue the command ‘sudo halt’. Once the OS has safely and fully shutdown, the Pi Supply will cut the power to the RBPi. If you would like to resume working, touch the on button, and the Pi Supply will restore power to the RBPi.
The second button on the Pi Supply is meant for a hard power off. In case of emergency, pressing this button will immediately cut the power to your RBPi. However, this button must only be used when absolutely necessary, as when your SBC has crashed or is in the frozen state and is refusing any attempts of revival. Note that use of this button increases the risk of file corruption on your SD card, if operated at the wrong moment.
One of the most amazing features of the Pi Supply is that it is able to distinguish between ‘sudo halt’ and ‘sudo reboot’. That means not only can Pi Supply shut down the power supplied to your single board computer when you give the halt command, but it can also reboot your SBC when you want, without you touching a single button or removing a single connector. That makes it almost as intelligent as the ATX power supply of your desktop.