In it he describes several examples where smartphones, particularly the iPhone
, have been morphed into first-rate medical devices with the potential to put clinical-level diagnostics in the hands of everyday users. Coincidentally, Topol was on a flight not long ago, returning from a lecture where he had spoken about a new device made by AliveCor. The pilot intoned an urgent, “is there a doctor on board?” In response, Topol took out the AliveCor prototype, recorded a highly accurate electrocardiogram (ECG) of an ailing passenger, and made a quick diagnosis from 35,000 feet.
As the leader in the smartphone revolution, the iPhone has been the platform of choice for early adopters in the health and quantified self
arenas. Even so, there are a few shortcomings to development on the iPhone which, at least among DIYers, has led to Android becoming the path forward. Apple’s single-vendor solution and sequestering of many low-level input/output details behind the premise of ease of use have made interfacing the device to external sensors both a difficult and expensive proposition.
While it can be nearly impossible to write an Android app that will work on every device out there, writing an app to work on one’s own smartphone or tablet is fairly straightforward. Another challenge to the smartphone as a medical device is that many important sensor variables are analog in nature. It is possible to use the analog-to-digital converter on the audio input for data acquisition, however in the absence of sophisticated multiplexing one is limited to a single channel (unless some kind of expansion device is used).
Run tracking and calorie counting apps can certainly be regarded among the successes of the smartphone, but without dedicated sensor hardware, the philosophy of “there’s an app for that” only goes so far. A host of products now available for Android let users with a little bit of technical know-how create powerful devices previously found only in the domain of hospitals and law enforcement. One of the most successful expansion boards that allows Android devices to control external instruments and to orchestrate the collection of a variety of sensor data is the IOIO board
. The system works well in wireless mode with most Bluetooth dongles, and its on-board FPGA
gives 25 I/O channels, including plenty for analog input. It also handles analog output via pulse width modulation (PWM).