NXP – LPC812: Smartphone Quick-Jack Solution

The flexible Smartphone Quick-Jack Solution adapts the standard 3.5mm stereo audio jack found on most iOS or Android smart devices into a self-powered data port and provides a universal interface for external sensors, switches and other devices. It gives both consumer and industrial product designers a simple, plug-and-go way to get data into an endless variety of control, monitoring, data collection, maintenance, medical and even fun applications.

The Smartphone Quick-Jack Solution includes a small PCB with an NXP LPC812 microcontroller, an energy harvesting circuit, a miniature joystick, and an expansion header. The LPC812 is an ARM Cortex M0+ microcontroller which manages the data transport, encoding and decoding data to be exchanged over the audio channels using the Manchester algorithm. The board’s expansion header makes it easy to connect myriad sensors, switches, HMI devices or other components that collect or log data from a variety of sources.

An energy harvesting circuit utilizes the right audio channel to supply power from the Smartphone to the Quick-Jack board. The supplied App for Android phones and iPhone displays joystick position and temperature, and can turn LEDs on the Quick-Jack board on and off.

Smartphones vary widely in design of the 3.5mm audio jack, so an application note is also provided with tips for designing the communication interface. Quick-Jack is designed to work with various iPhone platforms and Galaxy S3, and is an excellent reference for designing with other mobile platforms in mind.

Box Contents

  • Quick-Jack circuit board, ready for use with smart devices
  • To download the sample App please visit Google Play at the iPhone App Store and search for “NXP Quick-Jack”

This fully contained solution kit (OM13069) includes everything needed to get started:

  • Circuit board based on an LPC812 MCU
  • Header for connecting external debug probe, enabling code development
  • Energy harvesting design draws power from Smartphone audio signals
  • I/O devices: joystick, thermometer and LEDs
  • 3.5mm male stereo plus microphone audio jack
  • Expansion connector for attaching external sensor/switch/HMI devices
  • Downloadable free Apps for both iOS and Android, source code available
  • Battery (optional)