Raspberry Pi 3 Power Dongle

This entry in my Design Journal seeks to design an attachment for the Raspberry Pi 3 "computer on a card" to allow for simple power switch functions without unreasonably impeding use of form factor-reliant accessories such as cases.

Raspberry pi

The Raspberry Pi 3, Model B, is the most current iteration of the Raspberry Pi line, a series of British-produced low power "computer on a card" devices, made to introduce people to the world of hardware customization and low-power microcomputing. Equipped with a mobile processor and a gigabyte of RAM, the Pi 3 outputs via an HDMI connection, features onboard LAN, Bluetooth, and WiFi connectivity, and is powered by a 2.5 volt plug connected via a USB-Type B connector. Storage is managed using a MicroSD card slotted into the rear of the board. 

Power on?

One thing not included on the Pi 3, however, is a power switch. The small form factor and multiple features of the board did not allow much space for the placement of a switch on the main board. Currently, the Pi 3 automatically boots when connected to power via its USB-Type B port. To shut down the Pi 3, it must be unplugged. This can be annoying, as the power connection is located next to the HDMI port, on the side of the card. Whether this is towards the front or the rear of the machine is dependent on the case utilized. 

The Dongle

The proposed dongle would consist of a female port for the USB Type-B plug leading into a male port to plug into the female port on the Pi 3, separated by a simple break switch, operated by a slider located on top of the dongle's dorsal surface. The slider would break the connection between the two ports when switched to the off position, terminating the flow of power and switching off the device without removing and inserting the cable repeatedly, which would make a Pi 3 difficult to design around, and increase wear on the power port.