App stores and developer kits have made OS modularity common-place. The barriers for an software entrepreneur to entry are low to nil. Which has alters the market conditions rapidly and immediately. Hardware modularity is a different matter entirely. Companies like bug labs have bottom-up concepts for the rapid development and assembly of new concepts. Also Square has made mobile a mobile payment hack for the iPhone compelling to experience. Project Hijack takes this latter approach as the basis for a physically modular development platform, which chooses to work-around the main connector in favour of the the headphone jack.
Making accessories that tie into an iOS device’s Dock connector is an expensive proposition: it requires getting certain components from Apple and applying for a costly “Made for iPhone” (or iPod or iPad) license. However, it is possible to use the headphone jack for two-way data communication with an iPhone and also to power small electronic circuits. A group of students and faculty from the University of Michigan’s Electrical Engineering and Computer Science Department have developed a small device it calls the “HiJack” to make sensing peripherals easily accessible to those on a tight budget.
Project HiJack is a hardware and software platform for enabling communication between a small, low-power peripheral and an iDevice. The system uses a 22kHz audio signal, which is converted into 7.4mW of power at 47 percent efficiency. That power runs a TI MSP430 microcontroller as well as any attached electronics, and allows the HiJack to communicate with an iOS application. The components to build a HiJack cost as little as $2.34 in significant quantities.