Turn an audio jack into a self-powered data port

The Smartphone Quick-Jack Solution offers simple, plug-and-go connectivity for product designers to add features for wearable medical and fitness devices, gaming controllers, toys and diagnostics and maintenance tools. For apps which depend upon connectivity with external devices, it is unnecessary to use the device's only high-bandwidth USB/Lightning port. Wireless connectivity is one answer but that can also increase BOM cost in small devices and requires experience working with wireless protocols and an external power source, such as an energy harvester. By repurposing the audio jack, the solution makes communication with external devices as easy as plugging in headphones.

The Smartphone Quick-Jack Solution comprises a small board, a free example app for popular smartphone operating systems and design documentation. The board includes an LPC812 microcontroller, a standard extension header, an energy harvesting circuit and an onboard miniature joystick. The MCU decodes and encodes the Manchester algorithm (enabling use of the left audio channel for data transport) and communication with external peripherals. A source code for the LPC812 is available free and is ready to use with NXP LPCXpresso tools. The extension header enables the easy connection of sensors, switches, HMI peripherals or data- collection devices. The energy harvester draws power from the smartphone over the right audio channel to power the board and attached components, while the joystick visualises data/signals and controls the smartphone UI in the example application.

Jim Trent, Vice President & General Manager, Business Line Microcontrollers, NXP Semiconductors, "Smartphone user interfaces and connectivity features have revolutionised personal communication. The new Smartphone Quick-Jack Solution makes it exceptionally easy to take advantage of those same appealing features when designing end products, from something as sophisticated as a portable air-quality monitor, to something as rewarding as a child's toy with changeable/uploadable features."